Exhibit 4.1

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE FEDERAL OR ANY STATE SECURITIES LAWS AND MAY NOT BE SOLD, TRANSFERRED OR HYPOTHECATED IN ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS AS MAY BE APPLICABLE OR, AN OPINION OF COUNSEL THAT AN EXEMPTION FROM SUCH APPLICABLE LAWS EXIST.

NOTE

FOR VALUE RECEIVED, Authentidate Holding Corp., a Delaware corporation (the “Borrower”), with its principal offices located at 300 Connell Drive, Fifth Floor, Berkeley Heights, N.J. 07922, hereby promises to pay to the order of                      (the “Holder”) with its principal offices at                                                                  , or at such other address as the Holder designates in writing to the Borrower, the principal sum of One Hundred Thousand Dollars ($100,000) (the “Principal Amount”), on the Maturity Date.

This Promissory Note (“Note”) has been executed and issued pursuant to the terms of a Securities Purchase Agreement between the Borrower and the Holder dated of even date herewith (the “Purchase Agreement”) pursuant to which the Holder acquired this Note and common stock purchase warrants. Unless otherwise separately defined herein, all capitalized terms used in this Note shall have the same meaning as is set forth in the Purchase Agreement. This Note is a direct obligation of the Borrower and ranks senior to all Indebtedness issued by the Company after the date of this Note, other than Permitted Indebtedness, in accordance with the Purchase Agreement under the terms set forth herein. This Note is junior in right of payment as to a $200,000 secured promissory note issued by the Borrower on January 29, 2015.

1. Interest on this Note shall be computed at an annual rate of eight percent (8%), payable in arrears on the Maturity Date at which time all accrued and unpaid interest shall be immediately due and payable. All computations of interest payable hereunder shall be on the basis of a 365-day year and actual days elapsed in the period for which such interest is payable. Accrued interest on the outstanding principal amount shall be due and payable on the Maturity Date in cash. While in default, this Note shall bear interest at the rate of 16% per annum, or such maximum rate of interest allowable under the laws of the State of New York, if less. Payments of all amounts due hereunder shall be made in lawful money of the United States.

2. The “Maturity Date” of this Note shall be 180 days from the Issuance Date. The Holder at its sole discretion, may elect to extend the Maturity Date by an additional 90 days (an “Extension”); provided that the Holder shall give written notice to the Borrower at least 30 days before such Maturity Date. The Holder will have the right to elect up to two Extensions. Upon the election by the Holder to extend the Maturity Date of this Note, the Maturity Date shall automatically be amended to be the date that is 90 days following the initial Maturity Date, or in the case of a second Extension, 180 days following the initial Maturity Date.

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Payment of the Principal Amount of this Note shall be made upon the surrender of this Note to the Borrower, at its chief executive office (or such other office within the United States as shall be designated by the Borrower to the Holder hereof) (the “ Designated Office ”), in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts. If the Maturity Date (or any Extension of such Maturity Date) shall be a Saturday or a Sunday or shall be a legal holiday in the State of New York, then such action may be taken or such right may be exercised on the next succeeding day not a legal holiday.

3. Upon the occurrence and continuation of an Event of Default, the Holders of at least 50.1% of the Principal Amount of this Note (the “Majority Holders”), by written notice to the Borrower, may declare due and payable the entire unpaid balance of this Note then outstanding, together with accrued interest thereon, if any. For purposes of this Note, an “Event of Default” shall consist of any of the following events:

(a) The Borrower shall fail to pay any portion of the Principal Amount of this Note when the same becomes due and payable, whether at the Maturity Date or at any accelerated date of maturity or at any other date fixed for payment, and such default continues for 15 days or more.

(b) The Borrower shall voluntarily commence any case, proceeding or other action under any existing or future law of any jurisdiction, domestic or foreign, relating to bankruptcy, insolvency, or relief of debtors, seeking to have an order for relief entered with respect to it, or seeking to adjudicate it as bankrupt or insolvent, or seeking other relief with respect to its debts; or a court shall enter an order for relief or any such adjudication or appointment, which case, proceeding or action or order, adjudication, or appointment, as the case may be, remains undismissed, undischarged or unbonded for a period of 60 days, then, or any time thereafter during the continuance of any of such events.

(c) A final judgment for money damages or order for the payment of money damages in excess of One Hundred Thousand Dollars ($100,000) (exclusive of amounts covered by insurance) shall be entered against the Borrower, which has not been vacated or stayed within 45 days of entry.

(d) Any material representation or warranty of the Borrower herein shall prove to have been false in any material respect upon the date when made.

(e) The occurrence of a default (after giving effect to any grace periods or rights to cure held by the Borrower) under any material indebtedness of the Borrower resulting from other than the failure to timely pay interest or principal of such indebtedness which results in the acceleration of the maturity of such indebtedness.

(f) The Borrower shall liquidate, dissolve, terminate or suspend its business operations.

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(g) The Borrower shall have a change in control, provided, however that each such event may be waived by the Holder. A “change of control” means the occurrence of any of the following events: (i) any consolidation or merger of the Borrower in which the Borrower is not the continuing or surviving corporation or pursuant to which shares of stock of the Borrower would be converted into cash, securities or other property, other than a consolidation or merger of the Borrower in which holders of its common stock immediately prior to the consolidation or merger have substantially the same proportionate ownership of common stock of the surviving corporation immediately after the consolidation or merger as immediately before; (ii) a sale, lease, exchange or other transfer (in one transaction or a series of related transactions) of all or substantially all the assets of the Borrower; or (iii) the purchase by any person (as defined in Section 13(d) of the Securities Exchange Act of 1934), corporation or other entity, other than the Borrower or a wholly owned subsidiary of the Borrower, of shares pursuant to a tender or exchange offer, to acquire any stock of the Borrower (or securities convertible into stock) for cash, securities or any other consideration provided that, after consummation of the offer, such person, group, corporation or other entity is the beneficial owner (as defined in Rule 13d-3), directly or indirectly, of 50% or more of the outstanding stock of the Borrower.

(h) The Borrower shall breach any material covenant contained in the Purchase Agreement other than failure to make a payment of principal or interest and such breach continues for a period of 30 days after written notice of such failure has been given to the Borrower by the Majority Holders.

Nothing in this Section 3 is intended to restrict the Holder’s rights under any of the Transaction Documents or at law, and the Holder may exercise all such rights and remedies as and when they are available.

The Majority Holders may, on behalf of the Holders of all of the Notes, rescind and annul a declaration of an Event of Default, and its consequences if: (1) all existing Events of Default (other than pursuant to Section 3(a) of this Note) have been remedied, cured or waived, and (2) the rescission would not conflict with any judgment or decree of a court of competent jurisdiction.

4. Prepayment . The Borrower may not prepay this Note in whole or in part at any time without the Holder’s prior written consent; provided , however , the Holder may elect to require the Borrower to prepay the Note as provided for in Section 6.2 of the Purchase Agreement. In addition, upon the exercise of an Extension, than at any time and from time to time prior to the Maturity Date, upon no less than 20 days’ written notice by the Borrower to the Holder (the “Prepayment Notice”), all or a portion of the then outstanding Notes may be redeemed by the Borrower by payment of the Principal Amount (or portion thereof) to be redeemed at the end of such 20-day notice period (the “Redemption Amount”). The last day of such 20 day notice period shall be the “Redemption Date”. Provided the Borrower tenders the Redemption Amount on the Redemption Date, the Principal Amount of the Note noticed for prepayment shall, after the Redemption Date, be reduced by the Redemption Amount and thereafter represent only the right to receive, on the Maturity Date, the difference between the initial Principal Amount of this Note and the Redemption Amount.

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5. Transferability; Loss and Replacement .

(a) This Note has not been registered under the Securities Act, or the securities laws of any state or other jurisdiction. Neither this Note nor any interest or participation herein may be reoffered, sold, assigned, transferred, pledged, encumbered or otherwise disposed of (a “ Transfer ”) in the absence of registration under the Securities Act and any applicable state securities laws, or unless (i) such transaction is exempt from, or not subject to, registration under the Securities Act or the securities laws of any state or other jurisdiction and (ii) is made in compliance with applicable federal and state statutory resale restrictions, if any. The Holder by its acceptance of this Note agrees that it shall not offer, sell, assign, transfer, pledge, encumber or otherwise dispose of this Note or any portion thereof or interest therein other than in a minimum denomination of $50,000 principal amount (or any integral multiple of $10,000 in excess thereof) and then (other than with respect to a Transfer pursuant to a registration statement that is effective at the time of such Transfer) only (a) to the Borrower, (b) to an affiliate of the Holder, (c) to a Person it reasonably believes to be an “accredited investor” within the meaning of Rule 501(a) under the Securities Act, or (d) pursuant to a transaction in compliance with Rule 144 or Rule 144A under the Securities Act, and in the case of (b), (c) and (d) above in which the transferor furnishes the Borrower with such certifications, legal opinions or other information as the Borrower may reasonably request to confirm that such transfer is being made pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act as applicable.

(b) The Transfer of this Note is registrable on the books of the Borrower upon surrender of this Note for registration of Transfer at the Borrower’s designated office, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Borrower duly executed by, the Holder hereof or such Holder’s attorney duly authorized in writing, and thereupon one or more new Notes, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees. Prior to due presentation of this Note for registration of Transfer, the Borrower and any agent of the Borrower may treat the Person in whose name this Note is registered as the owner thereof for all purposes, whether or not this Note be overdue, and neither the Borrower nor any such agent shall be affected by notice to the contrary. Upon presentation of this Note for registration of Transfer at the Borrower’s designated office accompanied by (i) certification by the transferor that such Transfer is in compliance with the terms hereof and (ii) by a written instrument of Transfer in a form approved by the Borrower executed by the Holder, in person or by the Holder’s attorney thereunto duly authorized in writing, and including the name, address and telephone and fax numbers of the transferee and name of the contact person of the transferee, such Note shall be transferred on the Note Register, and a new Note of like tenor and bearing the same legends shall be issued in the name of the transferee and sent to the transferee at the address and c/o the contact person so indicated. Transfers and exchanges of Notes shall be subject to such additional restrictions as are set forth in the legends on the Notes and to such additional reasonable regulations as may be prescribed by the Borrower as specified herein. Successive registrations of Transfers as aforesaid may be made from time to time as desired, and each such registration shall be noted on the Note register.

(c) Upon receipt by the Borrower of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Note, and in the case of loss, theft or destruction, receipt

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of indemnity reasonably satisfactory to the Borrower and upon surrender and cancellation of this Note, if mutilated, the Borrower will deliver a new Note of like tenor and dated as of such cancellation, in lieu of such Note.

6. Miscellaneous .

(a) All makers and endorsers now or hereafter becoming parties hereto jointly and severally waive demand, presentment, notice of non-payment and protest.

(b) Neither this Note nor any term hereof may be amended or waived orally or in writing, except that any term of this Note and the other Notes may be amended and the observance of any term of this Note and the other Notes may be waived (either generally or in a particular instance and either retroactively or prospectively), and such amendment or waiver shall be applicable to all of the Notes, upon the approval of the Borrower and the Majority Holders; provided, however, that any amendment that would (i) reduce the principal amount of any Note, (ii) reduce the percentage in aggregate principal amount of Notes outstanding necessary to modify or amend the Notes; or (iii) modify this Section shall, in each case, require the approval of the holder of each Note to which such amendment shall apply.

(c) This Note and the rights and obligations of the Holder and of the undersigned shall be governed and construed in accordance with the laws of the State of New York.

(d) Upon the occurrence and during the continuance of an Event of Default under this Note, the Borrower shall, upon demand, pay to the Holder the amount of any and all reasonable costs and expenses (including reasonable attorneys’ fees) that Holder may incur in connection with the enforcement or collection of this Note.

(e) No failure or delay on the part of the Holders hereof in the exercise of any power, right or privilege hereunder shall operate as a waiver thereof, nor shall any single or partial exercise of any such power, right or privilege preclude other or further exercise thereof or of any other right, power or privilege. All rights and remedies existing hereunder are cumulative to, and not exclusive of, any rights or remedies.

(f) The Borrower hereby, to the fullest extent permitted by applicable law, waives presentment, demand, notice (including without limitation notice of default (except as otherwise specifically set forth herein), notice of protest, notice of intention to accelerate maturity, notice of acceleration of maturity and notice of nonpayment or dishonor), protest and all other demands and notices in connection with delivery, acceptance, performance, default, acceleration or enforcement of or under this Note, and the bringing of suit and diligence in taking any action to collect amounts owing hereunder or in proceeding against any of the rights and properties securing payment hereof, and is directly and primarily liable for the amount of all sums owing or to be owing hereon. No extension of the time for the payment of this Note made by agreement with any person now or hereafter liable for the payment of this Note shall operate to release, discharge, modify, change or affect the original liability of the Borrower under this Note.

(g) To the extent that Holder receives any payment on account of any of Borrower’s obligations under this Note, and any such payment(s) or any part thereof are

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subsequently invalidated, declared to be fraudulent or preferential, set aside, subordinate and/or required to be repaid to a trustee, receiver or any other person or entity under any bankruptcy act, state or federal law, common law or equitable cause, then, to the extent of such payment(s) received, the Borrower’s obligations or part thereof intended to be satisfied shall be revived and continue in full force and effect, as if such payment(s) had not been received by the Holder and applied on account of Borrower’s obligations.

(h) All notices, offers, acceptance and any other acts under this Note (except payment) shall be in writing, and shall be sufficiently given if delivered to the addressees in person, by FedEx or similar receipted next business day delivery, or by facsimile or email delivery followed by overnight next business day delivery to the Borrower at the address set forth above (or such other address as the Borrower may by notice to the Holder may designate from time to time) and to the Holder at the address set forth above (or such other address as the Holder by notice to the Borrower may designate from time to time). Time shall be counted to, or from, as the case may be, the date of delivery.

[ Signature Page Follows ]

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IN WITNESS WHEREOF, the Borrower has caused this Note to be executed as of the Issuance Date.

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Exhibit 4.2

THIS WARRANT AND THE UNDERLYING SHARES OF COMMON STOCK HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “SECURITIES ACT”), OR ANY OTHER SECURITIES LAWS, HAVE BEEN TAKEN FOR INVESTMENT, AND MAY NOT BE SOLD OR TRANSFERRED OR OFFERED FOR SALE OR TRANSFER UNLESS A REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND OTHER APPLICABLE SECURITIES LAWS WITH RESPECT TO SUCH SECURITIES IS THEN IN EFFECT, OR IN THE OPINION OF COUNSEL TO THE ISSUER OF THESE SECURITIES, SUCH REGISTRATION UNDER THE SECURITIES ACT AND OTHER APPLICABLE SECURITIES LAWS IS NOT REQUIRED.

WARRANT FOR THE PURCHASE OF SHARES OF

COMMON STOCK OF AUTHENTIDATE HOLDING CORP.

THIS IS TO CERTIFY that, for value received,                         , its successors and assigns (the “Holder”), is entitled to purchase, subject to the terms and conditions hereinafter set forth, 80,000 shares of Authentidate Holding Corp, a Delaware corporation (the “Company”) common stock, $0.001 par value per share (“Common Stock”), and to receive certificates for the Common Stock so purchased. The shares of Common Stock issuable upon exercise of this Warrant may be referred to herein as the “Warrant Shares”. The exercise price of this Warrant is $1.01 per share, subject to adjustment as provided below (the “Exercise Price”). This Warrant is one of the Warrants issued by the Company pursuant to that certain Securities Purchase Agreement dated as of the Issuance Date (the “Purchase Agreement”) pursuant to which the Company has offered and sold to the purchasers named therein certain promissory notes (the “Note”) and this Warrant.

1. Exercise Period and Vesting. To the extent vested (in accordance with the provisions described below) this Warrant shall be exercisable at any time by the Holder beginning on the first business day following the six-month anniversary of the date listed above (the “Initial Exercise Date”), and ending at 5:00 p.m., New York, New York time, five years from the Issuance Date (the “Exercise Period”). This Warrant will terminate automatically and immediately upon the expiration of the Exercise Period.

From and after the date on which this Warrant may first be exercised, this Warrant may be exercised to purchase Warrant Shares as follows: (i) an aggregate of 6,665 Warrant Shares shall be vested as of the day that is the one month anniversary of the Issuance Date and (ii) thereafter, provided that the Note has not been repaid in full, the remaining Warrant Shares shall vest in equal increments of 6,667 Warrant Shares on each of the next five (5) successive monthly anniversary dates of the Issuance Date. Following the day that is the 180 ^th anniversary date of the Issuance Date, this Warrant shall be exercisable for all of the 40,000 Warrant Shares covered by this Warrant until the expiration of the Exercise Period or such earlier date as set forth elsewhere in this Warrant. If the Note is extended for one or both of the 90 day extension periods described therein (each, an “Extension Period”), then a maximum of an additional 20,000 shares shall vest

over each applicable 90 day Extension Period as follows: (i) an aggregate of 6,666 Warrant Shares shall be vested as of the day that is the one month anniversary of the commencement of each Extension Period, and (ii) thereafter, provided that the Note has not been repaid in full, the remaining Warrant Shares eligible to vest during such Extension Period shall vest in equal monthly increments of 6,667 Warrant Shares on each of the two and three month anniversary dates of the commencement of an applicable Extension Period. Upon the payment by the Company of the entire principal amount of the Note for any reason, no additional Warrant Shares shall vest.

2 . Exercise of Warrant.

(a) Subject to the vesting provisions specified above, this Warrant may be exercised, in whole or in part, at any time and from time to time during the Exercise Period. Such exercise shall be accomplished by tender to the Company of an amount equal to the Exercise Price multiplied by the number of underlying shares being purchased (the “Purchase Price”), by wire transfer or by certified check or bank cashier’s check drawn on a United States bank in immediately available U.S. funds, payable to the order of the Company. As a condition of exercise, the Holder shall where applicable execute a customary investment letter and accredited investor questionnaire. The Holder’s right to exercise this Warrant is subject to compliance with any applicable laws and rules including Section 5 of the Securities Act of 1933.

(b) Upon receipt of the Purchase Price in Section 2(a), together with presentation and surrender to the Company of this Warrant with an executed subscription form in substantially the form attached hereto as Exhibit A (the “Subscription”), the Company will deliver to the Holder, as promptly as possible, a certificate or certificates representing the shares of Common Stock so purchased, registered in the name of the Holder or its transferee (as permitted under Section 3 below). With respect to any exercise of this Warrant, the Holder will for all purposes be deemed to have become the holder of record of the number of shares of Common Stock purchased hereunder on the date a properly executed Subscription and payment of the Purchase Price is received by the Company (the “Exercise Date”), irrespective of the date of delivery of the certificate evidencing such shares, except that, if the date of such receipt is a date on which the stock transfer books of the Company are closed, such person will be deemed to have become the holder of such shares at the close of business on the next succeeding date on which the stock transfer books are open. Fractional shares of Common Stock will not be issued upon the exercise of this Warrant. In lieu of any fractional shares that would have been issued but for the immediately preceding sentence, the Holder will be entitled to receive cash equal to the current market price of such fraction of a share of Common Stock on the trading day immediately preceding the Exercise Date. In the event this Warrant is exercised in part, the Company shall issue a new Warrant to the Holder covering the aggregate number of shares of Common Stock as to which this Warrant remains exercisable for. The Company acknowledges and agrees that this Warrant was issued on the Issuance Date. The issuance of Warrant Shares upon exercise of this Warrant shall be made without charge to Holder for any issuance tax in respect thereof or other cost incurred by the Company in connection with such exercise and the related issuance of Warrant Shares (other than any transfer taxes resulting from the issuance of Warrant Shares to any person other than Holder).

3. Transferability and Exchange.

(a) This Warrant, and the Common Stock issuable upon the exercise hereof, may not be sold, transferred, pledged or hypothecated unless the Company shall have been provided with an opinion of counsel reasonably satisfactory to the Company that such transfer is not in violation of the Securities Act of 1933 (the “Securities Act”), and any applicable state securities laws. Subject to the satisfaction of this condition, this Warrant and the underlying shares of Common Stock if not eligible to be sold under Rule 144 of the Securities Act shall be transferable from time to time by the Holders upon written notice to the Company. If this Warrant is transferred, in whole or in part, the Company may request the transferee to sign an investment letter and shall, upon surrender of this Warrant to the Company, deliver to each transferee a new Warrant evidencing the rights of such transferee to purchase the number of shares of Common Stock that such transferee is entitled to purchase pursuant to such transfer. The Company may place a legend similar to the legend at the top of this Warrant on any replacement Warrant and on each certificate representing shares issuable upon exercise of this Warrant or any replacement Warrants. Only registered Holder may enforce the provisions of this Warrant against the Company. A transferee of the original registered Holder becomes a registered Holder only upon delivery to the Company of the original Warrant and an original Assignment, substantially in the form set forth in Exhibit B attached hereto.

(b) This Warrant is exchangeable upon its surrender by the Holder to the Company for new Warrants of like tenor and date representing in the aggregate the right to purchase the number of shares purchasable hereunder, each of such new Warrants to represent the right to purchase such number of shares as may be designated by the Holder at the time of such surrender (not to exceed the aggregate number of shares underlying this Warrant).

4. Adjustments to Exercise Price and Number of Shares Subject to Warrant . The Exercise Price and the number of shares of Common Stock purchasable upon the exercise of this Warrant are subject to adjustment from time to time upon the occurrence of any of the events specified in this Section 4. For the purpose of this Section 4, “Common Stock” means shares now or hereafter authorized of any class of common stock of the Company, however designated, that has the right to participate in any distribution of the assets or earnings of the Company without limit as to per share amount (excluding, and subject to any prior rights of, any class or series of preferred stock).

(a) In case the Company shall (i) pay a dividend or make a distribution in shares of Common Stock to holders of shares of Common Stock, (ii) subdivide its outstanding shares of Common Stock into a greater number of shares, (iii) combine its outstanding shares of Common Stock into a smaller number of shares, or (iv) issue by reclassification of its shares of Common Stock other securities of the Company, then the Exercise Price in effect at the time of the record date for such dividend or on the effective date of such subdivision, combination or reclassification, and/or the number and kind of securities issuable on such date, shall be proportionately adjusted so that the Holder of the Warrant thereafter exercised shall be entitled to receive the aggregate number and kind of shares of Common Stock (or such other securities other than Common Stock) of the Company, at the same aggregate Exercise Price, that, if such Warrant had been exercised immediately prior to such date, the Holder would have owned upon such exercise and been entitled to receive by virtue of such dividend, distribution, subdivision,

combination or reclassification. It is agreed that the adjustments provided for in this Section 4(a) will be made with the intent and, as nearly as practicable, the effect that neither the percentage of the total equity of the Company obtainable on exercise of this Warrants, nor the total exercise price payable for such percentage upon exercise, will be affected by any event described in this Section 4(a). Such adjustment shall be made successively whenever any event listed above shall occur.

(b) If securities of the Company or securities of any subsidiary of the Company are distributed pro rata to holders of Common Stock, such number of securities will be distributed to the Holder or its assignee upon exercise of its rights hereunder as such Holder or assignee would have been entitled to if this Warrant had been exercised prior to the record date for such distribution. The provisions with respect to adjustment of the Common Stock provided in this Section 4 will also apply to the securities to which the Holder or its assignee is entitled under this Section 4(c) .

(c) Notwithstanding any provision herein to the contrary, no adjustment in the Exercise Price shall be required unless such adjustment would require an increase or decrease of at least 1% in the Exercise Price; provided , however , that any adjustments which by reason of this Section 4(c) are not required to be made shall be carried forward and taken into account in any subsequent adjustment. All calculations under this Section 4 shall be made to the nearest cent or the nearest one-hundredth of a share, as the case may be.

(d) Intentionally omitted.

(e) If the Company merges or consolidates into or with another corporation or entity, or if another corporation or entity merges into or with the Company (excluding such a merger in which the Company is the surviving or continuing corporation and which does not result in any reclassification, conversion, exchange, or cancellation of the outstanding shares of Common Stock), or if all or substantially all of the assets or business of the Company are sold or transferred to another corporation, entity, or person, then, as a condition to such consolidation, merger, or sale (any a “Transaction”), lawful and adequate provision shall be made whereby the Holder shall have the right from and after the Transaction to receive, upon exercise of this Warrant and upon the terms and conditions specified herein and in lieu of the shares of the Common Stock that would have been issuable if this Warrant had been exercised immediately before the Transaction, such shares of stock, securities, or assets as the Holder would have owned immediately after the Transaction if the Holder have exercised this Warrant immediately before the effective date of the Transaction.

(f) In case any event shall occur as to which the other provisions of this Section 4 are not strictly applicable but the failure to make any adjustment would not fairly protect the purchase rights represented by this Warrant in accordance with the essential intent and principles hereof, then, in each such case, the Company shall effect such adjustment, on a basis consistent with the essential intent and principles established in this Section 4, as may be necessary to preserve, without dilution, the purchase rights represented by this Warrant.

5. No Registration Rights. Issuance of this Warrant and the Warrant Shares (together, the “Securities”) have not been registered under the Securities Act. The Holder

acknowledges that the Warrant is being issued, and the Warrant Shares will be issued, on the basis of the statutory exemption provided by section 4(a)(2) of the Securities Act relating to transactions by an issuer not involving any public offering, and that the Company’s reliance upon this statutory exemption is based in part upon the representations made by the Holder. The Holder agrees that no sale, assignment or transfer of the Securities shall be valid or effective, and the Company shall not be required to give any effect to any such sale, assignment or transfer, unless (i) the sale, assignment or transfer of the Securities is registered under the Securities Act, or (ii) the Securities are sold, assigned or transferred in accordance with all the requirements and limitations of Rule 144 under the Securities Act or such sale, assignment, or transfer is otherwise exempt from registration under the Securities Act. The Holder represents and warrants that he has acquired this Warrant and will acquire the Warrant Shares for his own account for investment and not with a view to the sale or distribution thereof or the granting of any participation therein, and that he has no present intention of distributing or selling to others any of such interest or granting any participation therein. The Holder acknowledges that the Securities must be held indefinitely unless a subsequent disposition thereof is registered under the Securities Act or registered or qualified under any applicable state securities laws or is exempt from registration and/or qualification. The Holder is able to bear the economic risk of such investment and to afford a complete loss thereof and is an “accredited investor” as such term is defined in Rule 501 (the provisions of which are known to the Holder) promulgated under the Securities Act.

When exercised, the stock certificates shall bear the following legend:

“The securities represented by this certificate have not been registered under the Securities Act of 1933 (the “Securities Act”), and may not be offered for sale or sold except pursuant to (i) an effective registration statement under the Securities Act, or (ii) an opinion of counsel to the issuer of these securities that an exemption from registration under the Securities Act is available.

6. Reservation of Shares. The Company agrees at all times to reserve and hold available out of its authorized but unissued shares of Common Stock the number of shares of Common Stock issuable upon the full exercise of this Warrant. The Company further covenants and agrees that all shares of Common Stock that may be delivered upon the exercise of this Warrant will, upon delivery, be fully paid and nonassessable and free from all taxes, liens and charges with respect to the purchase thereof hereunder.

7. Notices to Holder. Upon any adjustment of the Exercise Price pursuant to Section 4, the Company shall promptly thereafter cause to be given to the Holder written notice of such adjustment. Such notice shall include the Exercise Price (and/or the number of shares of Common Stock issuable upon the exercise of this Warrant) after such adjustment, and shall set forth in reasonable detail the Company’s method of calculation and the facts upon which such calculations were based. Where appropriate, such notice shall be given in advance and included as a part of any notice required to be given under the other provisions of this Section 7.

In the event of (a) any fixing by the Company of a record date with respect to the holders of any class of securities of the Company for the purpose of determining which of such holders are entitled to dividends or other distributions, or any rights to subscribe for, purchase or

otherwise acquire any shares of capital stock of any class or any other securities or property, or to receive any other right, (b) any capital reorganization of the Company, or reclassification or recapitalization of the capital stock of the Company or any transfer of all or substantially all of the assets or business of the Company to, or consolidation or merger of the Company with or into, any other entity or person, or (c) any voluntary or involuntary dissolution or winding up of the Company, then and in each such event the Company will give the Holder a written notice specifying, as the case may be (i) the record date for the purpose of such dividend, distribution, or right, and stating the amount and character of such dividend, distribution, or right; or (ii) the date on which any such reorganization, reclassification, recapitalization, transfer, consolidation, merger, conveyance, dissolution, liquidation, or winding up is to take place and the time, if any is to be fixed, as of which the holders of record of Common Stock (or such capital stock or securities receivable upon the exercise of this Warrant) shall be entitled to exchange their shares of Common Stock (or such other stock securities) for securities or other property deliverable upon such event. Notwithstanding anything else in this Section 7 to the contrary, however, if the date on which the Company is obliged to provide any notice hereunder to the Holders is prior to a public announcement relating to the events set forth and on such date the Company’s securities are traded or quoted on any recognized national securities exchange or quotation system, then such notice shall be provided to each Holder simultaneously with the notice provided to the Company’s common stockholders. Failure to give such notice, or any defect therein, shall not, however, affect the legality or validity of any such action.

8. No Rights as a Shareholder. This Warrant does not entitle the Holder to any voting rights or other rights as a shareholder of the Company, nor to any other rights whatsoever except the rights herein set forth.

9. Additional Covenants of the Company. For so long as the Common Stock is listed for trading or trades on any national securities exchange including, the Company shall, upon issuance of any shares for which this Warrant is exercisable, at its expense, promptly obtain and maintain the listing or qualifications for trading of such shares.

The Company shall comply with the reporting requirements of Sections 13 and 15(d) of the Securities Exchange Act of 1934 for so long as and to the extent that such requirements apply to the Company.

The Company shall not, by amendment of its Certificate of Incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issuance or sale of securities, or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant. Without limiting the generality of the foregoing, the Company (a) shall comply with Section 6 of this Warrant and have available sufficient shares of Common Stock to be issued from time to time upon exercise of this Warrant, (b) will not increase the par value of any shares of Common Stock issuable upon exercise of this Warrant above the amount payable therefor upon such exercise, and (c) will take all such actions as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and nonassessable stock.

10. Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of the Company, the Holder and their respective successors and permitted assigns.

11. Notices. The Company agrees to maintain a ledger of the ownership of this Warrant (the “Ledger”). Any notice hereunder shall be given by FedEx or other overnight delivery service for delivery on the next business day if to the Company, at its principal executive office and, if to the Holder, to his address shown in the Ledger of the Company; provided , however , that either the Company or the Holder may at any time on three days’ written notice to the other designate or substitute another address where notice is to be given. Notice shall be deemed given and received after a FedEx or other overnight delivery service is delivered to the carrier.

12. Severability. Every provision of this Warrant is intended to be severable. If any term or provision hereof is illegal or invalid for any reason whatsoever, such illegality or invalidity shall not affect the remainder of this Warrant.

13. Governing Law. This Warrant shall be governed by and construed in accordance with the laws of the State of New York without giving effect to the principles of choice of laws thereof.

14. Entire Agreement. This Warrant (including the Exhibits attached hereto) constitutes the entire understanding between the Company and the Holder with respect to the subject matter hereof, and supersedes all prior negotiations, discussions, agreements and understandings relating to such subject matter.

15. Waivers and Amendments. No course of dealing between the Company and the Holder hereof shall operate as a waiver of any right of any Holder hereof, and no delay on the part of the Holder in exercising any right hereunder shall so operate. This Warrant may be amended or waived only by a written instrument executed by the Company and the Holder hereof. Any amendment shall be endorsed upon this Warrant, and all future Holders shall be bound thereby.

16. Loss, Destruction, Etc. Upon receipt by the Company of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant Certificate, and, in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to it, and reimbursement to the Company of all reasonable expenses incidental thereto, and upon surrender and cancellation of the Warrants, if mutilated, the Company will make and deliver a new Warrant of like tenor, in lieu thereof and any such lost, stolen, destroyed or mutilated warrant shall thereupon become void.

17. Acceptance . Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

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[Signature Page To Warrant]

IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its duly authorized officer as of the date first set forth above.

Exhibit A to the Warrant

SUBSCRIPTION FORM

(To be Executed by the Holder to Exercise the Rights To Purchase Common Stock Evidenced by the Within Warrant)

Section 1 - P lease complete the following:

I am making payment of the full exercise price for such shares at an Exercise Price per share of $        as provided for in such Warrant. The total exercise price payable is $        . Such payment takes the form of (check applicable box or boxes):

I request that a certificate for the Common Stock be issued in the name of the undersigned and be delivered to the undersigned at the address stated below. If the Common Stock is not all of the shares purchasable pursuant to the Warrant, I request that a new Warrant of like tenor for the balance of the remaining shares purchasable thereunder be delivered to me at the address stated below.

In connection with the issuance of the Common Stock, I hereby represent to the Company that I am acquiring the Common Stock for my own account for investment and not with a view to, or for resale in connection with, a distribution of the shares within the meaning of the Securities Act of 1933 (the “Securities Act”).

I am            am not              [ please initial one ] an accredited investor for at least one of the reasons on Exhibit A-1 to the Warrant. If the SEC has amended the rule defining the definition of accredited investor, I acknowledge that as a condition to exercise the Warrant, the Company may request updated information regarding the Holder’s status as an accredited investor. My exercise of the Warrant shall be in compliance with the applicable exemptions under the Securities Act and applicable state law

I understand that if at this time the Common Stock has not been registered under the Securities Act, I must hold such Common Stock indefinitely unless the Common Stock is subsequently registered and qualified under the Securities Act or is exempt from such registration and qualification. I shall make no transfer or disposition of the Common Stock unless (a) such transfer or disposition can be made without registration under the Securities Act by reason of a specific exemption from such registration and such qualification, or (b) a registration statement has been filed pursuant to the Securities Act and has been declared effective with respect to such disposition. I agree that each certificate representing the Common Stock delivered to me shall bear substantially the same as set forth on the front page of the Warrant.

I further agree that the Company may place stop transfer orders with its transfer agent same effect as the above legend. The legend and stop transfer notice referred to above shall be removed only upon my furnishing to the Company of an opinion of counsel to the Company to the effect that such legend may be removed.

Exhibit A-1 to the Warrant

For Individual Investors Only:

1. A person who has an individual net worth, or combined net worth (with his or her spouse) who has, in excess of $1,000,000. For purposes of this question, “net worth” means the excess of total assets at fair market value. The fair market value of my primary residence and the indebtedness on mortgages or deeds of trust related to such residence shall be excluded unless the indebtedness exceeds the fair market value .

2a. A person who had individual income (exclusive of any income attributable to the person’s spouse) of more than who has $200,000 in each of the two most recently completed years and who reasonably expects to have an individual income in excess of $200,000 this year.

2b. Alternatively, a person, who with his or her spouse, has joint income in excess of $300,000 in each applicable year.

3. A director or executive officer of the Company.

Other Investors:

4. Any bank as defined in Section 3(a)(2) of the Securities Act of 1933 (“Securities Act”) whether acting in its individual or fiduciary capacity; any broker or dealer registered pursuant to section 15 of the Securities Exchange Act of 1934; insurance company as defined in Section 2(13) of the Securities Act; investment company registered under the Investment Company Act of 1940 or a business development company as defined in Section 2(a)(48) of that Act; Small Business Investment Company licensed by the U.S. Small Business Administration under Section 301(c) or (d) of the Small Business Investment Act of 1958; any plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of a state or its political subdivisions, for the benefit of its employees, if such plan has total assets in excess of $5,000,000; employee benefit plan within the meaning of Title I of the Employee Retirement Income Security Act of 1974, if the investment decision is made by a plan fiduciary, as defined in Section 3(21) of such Act, which is either a bank, savings and loan association, insurance company, or registered investment advisor, or if the employee benefit plan has total assets in excess of $5,000,000, or if a self-directed plan, with investment decisions made solely by persons that are accredited investors.

5. A private business development company as defined in Section 202(a)(22) of the Investment Advisors Act of 1940.

6. An organization described in Section 501(c)(3) of the Internal Revenue Code, corporation, Massachusetts or similar business trust or partnership, not formed for the specific purpose of acquiring the securities offered, with total assets in excess of $5,000,000.

7. A trust, with total assets in excess of $5,000,000, not formed for the specific purpose of acquiring the securities offered, whose purchase is directed by a sophisticated person as described in Rule 506(b)(2)(ii) of the Securities Act.

8. An entity in which all of the equity owners are accredited investors.

For Value Received                                          hereby sells, assigns and transfers to                                          the Warrant attached hereto and the rights represented thereby to purchase                  shares of Common Stock in accordance with the terms and conditions hereof, and does hereby irrevocably constitute and appoint                                          as attorney to transfer such Warrant on the books of the Company with full power of substitution.

Exhibit 4.3

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE FEDERAL OR ANY STATE SECURITIES LAWS AND MAY NOT BE SOLD, TRANSFERRED OR HYPOTHECATED IN ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS AS MAY BE APPLICABLE OR, AN OPINION OF COUNSEL THAT AN EXEMPTION FROM SUCH APPLICABLE LAWS EXIST.

PROMISSORY NOTE

FOR VALUE RECEIVED, Authentidate Holding Corp., a Delaware corporation (the “Borrower”), with its principal offices located at 300 Connell Drive, Fifth Floor, Berkeley Heights, N.J. 07922, hereby promises to pay to the order of                      (the “Holder”) at such address as the Holder designates in writing to the Borrower, the principal sum of Nine Hundred Fifty Thousand Dollars ($950,000) (the “Principal Amount”), on the earlier of the Maturity Date stated above, or the Accelerated Payment Date (as defined below). This Note is a direct obligation of the Borrower.

1. Interest on this Note shall be computed at the rate of 0.48% per month, payable in arrears on the Maturity Date or the Accelerated Payment Date, at which time all accrued and unpaid interest shall be immediately due and payable. All computations of interest payable hereunder shall be on the basis of a 365-day year and actual days elapsed in the period for which such interest is payable. Accrued interest on the outstanding principal amount shall be due and payable on the Maturity Date or the Accelerated Payment Date in cash. Payments of all amounts due hereunder shall be made in lawful money of the United States.

2. Payment of the Principal Amount of this Note, and interest thereon, shall be made upon the surrender of this Note to the Borrower, at its chief executive office (or such other office within the United States as shall be designated by the Borrower to the Holder hereof) (the “ Designated Office ”), in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts. If the Maturity Date (or the Accelerated Payment Date) shall be a Saturday or a Sunday or shall be a legal holiday in the State of New York, then such action may be taken or such right may be exercised on the next succeeding day not a legal holiday. For purposes of this note, a “month” shall mean a 30 day period.

3. As used herein, the term “Accelerated Payment Date” shall mean the closing by the Borrower of a sale of equity or debt securities of the Company, or series of closings, as part of the same transaction, of equity or debt securities within a period of 30 days, in the gross amount of at least $950,000.

4. Events of Default .

(a) For purposes of this Note, an “Event of Default” shall consist of any of the following events:

(1) The Borrower shall fail to pay any portion of the Principal Amount of this Note when the same becomes due and payable, whether at the Maturity Date or at any accelerated date of maturity or at any other date fixed for payment, and such default continues for 10 days or more.

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(2) The Borrower shall voluntarily commence any case, proceeding or other action under any existing or future law of any jurisdiction, domestic or foreign, relating to bankruptcy, insolvency, or relief of debtors, seeking to have an order for relief entered with respect to it, or seeking to adjudicate it as bankrupt or insolvent, or seeking other relief with respect to its debts; or a court shall enter an order for relief or any such adjudication or appointment, which case, proceeding or action or order, adjudication, or appointment, as the case may be, remains undismissed, undischarged or unbonded for a period of 30 days, then, or any time thereafter during the continuance of any of such events.

(3) A final judgment for money damages or order for the payment of money damages in excess of One Hundred Thousand Dollars ($100,000) (exclusive of amounts covered by insurance) shall be entered against the Borrower, which has not been vacated or stayed within 15 days of entry.

(4) Any material representation or warranty of the Borrower herein shall prove to have been false in any material respect upon the date when made.

(5) The occurrence of a default (after giving effect to any grace periods or rights to cure held by the Borrower) under any material indebtedness of the Borrower resulting from other than the failure to timely pay interest or principal of such indebtedness which results in the acceleration of the maturity of such indebtedness.

(6) The Borrower shall liquidate, dissolve, terminate or suspend its business operations.

(b) Acceleration of Payment . If an Event of Default (other than an Event of Default specified in Section 4(a)(2) hereof with respect to the Company) occurs and is continuing, the Holder, by written notice to the Company, may declare due and payable the principal of this Note. Upon a declaration of acceleration, such principal shall be immediately due and payable. If an Event of Default specified in Section 4(a)(2) occurs with respect to the Company, the principal of this Note shall become and be immediately due and payable, without any declaration or other act on the part of the Holder. Further, upon an Event of Default, from such date of the Event of Default, Holder shall be entitled, and this Note shall bear additional interest at the rate of one (1%) percent per month.

(c)  Collections . If an Event of Default with respect to this Note occurs and is continuing, the Holder may pursue any available remedy by proceeding at law or in equity to collect the defaulted payment or to enforce the performance of any provision of this Note. Notwithstanding any other provision in this Note, the Holder of this Note shall have the right, which is absolute and unconditional, to receive payment of the principal in respect of the Notes held by the Holder, on or after the final Maturity Date, or to bring suit for the enforcement of any such payment on or after such date, and such rights shall not be impaired or affected adversely without the consent of the Holder.

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(d)  No Exclusive Right or Remedy . Except as otherwise provided herein, no right or remedy conferred in this Note upon the Holder is intended to be exclusive of any other right or remedy, and every right and remedy shall, to the extent permitted by law, be cumulative and in addition to every other right and remedy given hereunder or hereafter existing at law or in equity or otherwise. The assertion or employment of any right or remedy hereunder, or otherwise, shall not prevent the concurrent assertion or employment of any other appropriate right or remedy. No delay or omission of the Holder of this Note to exercise any right or remedy accruing upon any Event of Default shall impair any such right or remedy or constitute a waiver of any such Event of Default or any acquiescence therein. Every right and remedy given by this Section 4 or by law to the Holder may be exercised from time to time, and as often as may be deemed expedient, by the Holder.

5. Transferability; Loss and Replacement .

(a) This Note has not been registered under the Securities Act, or the securities laws of any state or other jurisdiction. Neither this Note nor any interest or participation herein may be reoffered, sold, assigned, transferred, pledged, encumbered or otherwise disposed of (a “ Transfer ”) in the absence of registration under the Securities Act and any applicable state securities laws, or unless (i) such transaction is exempt from, or not subject to, registration under the Securities Act or the securities laws of any state or other jurisdiction and (ii) is made in compliance with applicable federal and state statutory resale restrictions, if any. The Holder by its acceptance of this Note agrees that it shall not offer, sell, assign, transfer, pledge, encumber or otherwise dispose of this Note or any portion thereof or interest therein other than in a minimum denomination of $50,000 principal amount (or any integral multiple of $10,000 in excess thereof) and then (other than with respect to a Transfer pursuant to a registration statement that is effective at the time of such Transfer) only (a) to the Borrower, (b) to an affiliate of the Holder, (c) to a Person it reasonably believes to be an “accredited investor” within the meaning of Rule 501(a) under the Securities Act, or (d) pursuant to a transaction in compliance with Rule 144 or Rule 144A under the Securities Act, and in the case of (b), (c) and (d) above in which the transferor furnishes the Borrower with such certifications, legal opinions or other information as the Borrower may reasonably request to confirm that such transfer is being made pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act as applicable.

(b) By receipt and acceptance of this Note, Holder and any permitted transferee represents and warrants to the Borrower that (i) it is an “accredited investor” as defined in Rule 501(a)(1), (a)(2), (a)(3), (a)(7) or (a)(8) under the Securities Act; (ii) either alone or together with its representatives, has such knowledge, sophistication and experience in business and financial matters so as to be capable of evaluating the merits and risks of the prospective investment in the Note, and has so evaluated the merits and risks of such investment; (iii) is able to bear the economic risk of an investment in the Note and, at the present time, is able to afford a complete loss of such investment; (iv) understands that the Note will be characterized as “restricted securities” under U.S. federal securities laws and have not been and are not being registered under the Securities Act or any state securities laws, must be held indefinitely and may not be offered for sale, sold, assigned or

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transferred except in accordance therewith and (vii) it has reviewed the Borrower’s filings with the Securities and Exchange Commission (“SEC Report”) and has been afforded (A) the opportunity to ask such questions as it has deemed necessary of, and to receive answers from, representatives of the Borrower concerning the terms and conditions of this Note and the merits and risks of the prospective investment in the Note and the Borrower generally and, (B) it has access to information about the Borrower and its subsidiaries and their respective financial condition, results of operations, business, properties, management and prospects sufficient to enable it to evaluate the terms and conditions of this Note and the merits and risks of the prospective investment in the Borrower.

(c) The Transfer of this Note is registrable on the books of the Borrower upon surrender of this Note for registration of Transfer at the Borrower’s designated office, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Borrower duly executed by, the Holder hereof or such Holder’s attorney duly authorized in writing, and thereupon one or more new Notes, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees. Prior to due presentation of this Note for registration of Transfer, the Borrower and any agent of the Borrower may treat the Person in whose name this Note is registered as the owner thereof for all purposes, whether or not this Note be overdue, and neither the Borrower nor any such agent shall be affected by notice to the contrary. Upon presentation of this Note for registration of Transfer at the Borrower’s designated office accompanied by (i) certification by the transferor that such Transfer is in compliance with the terms hereof and (ii) by a written instrument of Transfer in a form approved by the Borrower executed by the Holder, in person or by the Holder’s attorney thereunto duly authorized in writing, and including the name, address and telephone and fax numbers of the transferee and name of the contact person of the transferee, such Note shall be transferred on the Note Register, and a new Note of like tenor and bearing the same legends shall be issued in the name of the transferee and sent to the transferee at the address and c/o the contact person so indicated. Transfers and exchanges of Notes shall be subject to such additional restrictions as are set forth in the legends on the Notes and to such additional reasonable regulations as may be prescribed by the Borrower as specified herein. Successive registrations of Transfers as aforesaid may be made from time to time as desired, and each such registration shall be noted on the Note register. No Transfer shall be allowed except to an “accredited investor” as defined under the rules and regulations of the Securities and Exchange Commission.

(d) Upon receipt by the Borrower of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Note, and in the case of loss, theft or destruction, receipt of indemnity reasonably satisfactory to the Borrower and upon surrender and cancellation of this Note, if mutilated, the Borrower will deliver a new Note of like tenor and dated as of such cancellation, in lieu of such Note.

6. Miscellaneous .

(a) All makers and endorsers now or hereafter becoming parties hereto jointly and severally waive demand, presentment, notice of non-payment and protest.

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(b) Neither this Note nor any term hereof may be amended or waived orally or in writing, except that any term of this Note may be amended and the observance of any term of this Note may be waived (either generally or in a particular instance and either retroactively or prospectively), and such amendment or waiver shall be applicable upon the approval of the Borrower and the Holder.

(c) This Note and the rights and obligations of the Holder and of the undersigned shall be governed and construed in accordance with the laws of the State of New York.

(d) Upon the occurrence and during the continuance of an Event of Default under this Note, the Borrower shall, upon demand, pay to the Holder the amount of any and all reasonable costs and expenses (including reasonable attorneys’ fees) that Holder may incur in connection with the enforcement or collection of this Note.

(e) No failure or delay on the part of the Holders hereof in the exercise of any power, right or privilege hereunder shall operate as a waiver thereof, nor shall any single or partial exercise of any such power, right or privilege preclude other or further exercise thereof or of any other right, power or privilege. All rights and remedies existing hereunder are cumulative to, and not exclusive of, any rights or remedies.

(f) The Borrower hereby, to the fullest extent permitted by applicable law, waives presentment, demand, notice (including without limitation notice of default (except as otherwise specifically set forth herein), notice of protest, notice of intention to accelerate maturity, notice of acceleration of maturity and notice of nonpayment or dishonor), protest and all other demands and notices in connection with delivery, acceptance, performance, default, acceleration or enforcement of or under this Note, and the bringing of suit and diligence in taking any action to collect amounts owing hereunder or in proceeding against any of the rights and properties securing payment hereof, and is directly and primarily liable for the amount of all sums owing or to be owing hereon. No extension of the time for the payment of this Note made by agreement with any person now or hereafter liable for the payment of this Note shall operate to release, discharge, modify, change or affect the original liability of the Borrower under this Note.

(g) To the extent that Holder receives any payment on account of any of Borrower’s obligations under this Note, and any such payment(s) or any part thereof are subsequently invalidated, declared to be fraudulent or preferential, set aside, subordinate and/or required to be repaid to a trustee, receiver or any other person or entity under any bankruptcy act, state or federal law, common law or equitable cause, then, to the extent of such payment(s) received, the Borrower’s obligations or part thereof intended to be satisfied shall be revived and continue in full force and effect, as if such payment(s) had not been received by the Holder and applied on account of Borrower’s obligations.

(h) All notices, offers, acceptance and any other acts under this Note (except payment) shall be in writing, and shall be sufficiently given if delivered to the addressees in person, by FedEx or similar receipted next business day delivery, or by facsimile or email delivery followed by overnight next business day delivery to the Borrower at the address set forth above (or such other address as the Borrower may by notice to the Holder may designate from time to time) and to the Holder at the address set forth above (or such other address as the Holder by notice to the Borrower may designate from time to time). Time shall be counted to, or from, as the case may be, the date of delivery.

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IN WITNESS WHEREOF, the Borrower has caused this Note to be executed as of the Issuance Date.

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Exhibit 4.4

NEITHER THIS WARRANT NOR ANY OF THE SECURITIES ISSUABLE HEREUNDER HAVE BEEN REGISTERED UNDER THE SECURITIES ACT (AS DEFINED BELOW), OR APPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED (I) IN THE ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT, OR (B) AN OPINION OF COUNSEL, IN A GENERALLY ACCEPTABLE FORM, THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT (II) UNLESS SOLD OR TRANSFERRED TO A “QUALIFIED INSTITUTIONAL BUYER” WITHIN THE MEANING OF RULE 144A UNDER THE SECURITIES ACT OR (III) UNLESS SOLD PURSUANT TO RULE 144 OR RULE 144A UNDER SAID ACT.

AUTHENTIDATE HOLDING CORP.

COMMON STOCK PURCHASE WARRANT

THIS CERTIFIES THAT, for value received, the Holder is entitled to purchase, and AUTHENTIDATE HOLDING CORP. , a Delaware corporation (the “ Company ”), promises and agrees to sell and issue to the Holder, at any time, or from time to time, during the Exercise Period, up to 99,500 shares of Common Stock, par value $0.001 per share (the “ Common Stock ”), of the Company, at the Exercise Price, subject to the provisions and upon the terms and conditions hereinafter set forth. This Warrant is issued by the Company in connection with the Company’s sale and issuance to the original Holder hereof of a certain promissory note in the principal amount of $950,000 (the “ Note ”), which Note is issued as of the Issue Date of this Warrant.

1. Definitions of Certain Terms . In addition to the terms defined elsewhere in this Warrant, the following terms have the following meanings:

(a) “ Business Day ” means a day on which banks are open for business in the city of New York.

(b) “ Commission ” means the U.S. Securities and Exchange Commission.

(c) “ Exchange Act ” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

(d) “ Exercise Price ” means the price at which the Holder may purchase one share of Common Stock upon exercise of this Warrant as determined from time to time pursuant to the provisions hereof. The initial Exercise Price is $1.01 per share, subject to adjustment as provided herein.

(e) “ Expiration Date ” means the 54-month anniversary of the Initial Exercise Date.

(f) “ Holder ” means a record holder of the Warrant or shares of Common Stock obtained or obtainable upon exercise of the Warrant, as applicable. The initial Holder is                     .

(g) “ Initial Exercise Date ” means the first Business Day following the six-month anniversary of the Issue Date.

(h) “ Issue Date ” means February     , 2015.

(i) “ Securities Act ” means the Securities Act of 1933, as amended.

(j) “ Warrant ” means this Common Stock purchase warrant and any warrant or warrants hereafter issued as a consequence of the exercise or transfer of this warrant in whole or in part.

2. Exercise of Warrant .

(a) Manner of Exercise .

(i) Cash Exercise . This Warrant may be exercised, in whole or in part, at any time or from time to time, during the period commencing as of 9:30:01 a.m., New York time, on the Initial Exercise Date and ending as of 5:30 p.m., New York time, on the Expiration Date (the “ Exercise Period ”), for 99,500 fully paid and non-assessable shares of Common Stock (the “ Warrant Shares ”), for an exercise price per share equal to the Exercise Price, by delivery to the Company at its headquarters, or at such other place as is designated in writing by the Company, of:

(1) a duly executed Notice of Exercise, substantially in the form of Attachment I attached hereto and incorporated by reference herein;

(2) this Warrant; and

(3) subject to Section 2(a)(ii) below, payment of an amount in cash equal to the product of the Exercise Price multiplied by the number of Warrant Shares being purchased upon such exercise, with such payment being in the form of a wire transfer of immediately available U.S. funds to an account designated in writing by the Company.

The date on which the Company receives the Notice of Exercise, this Warrant, and the Exercise Price payable with respect to the Warrant Shares being purchased shall be deemed to be the date of exercise (the “ Date of Exercise ”).

(ii) Cashless Exercise . Notwithstanding the provisions of Section 2(a)(i)(3) above (requiring payment by wire transfer), the Company agrees that, if at the time of exercise hereof there is no effective registration statement registering, or the prospectus contained therein is not available for the issuance of the Warrant Shares to the Holder, then Holder shall have the right at such time to exercise this Warrant in full or in part on a cashless basis, computed using the following formula:

Where:

X = The number of Warrant Shares to be issued to the Holder pursuant to this cashless exercise;

Y = The number of Warrant Shares in respect of which the net issue election is made;

A = The Fair Market Value (as defined below) of one Warrant Share at the time the cashless exercise election is made; and

B = The Exercise Price then in effect at the time of such exercise.

The term “Fair Market Value” shall mean, on any given day: (A) if the class of Warrant Shares is exchange-traded, the average of the closing sales prices per share of the class of Warrant Shares for the

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ten (10) consecutive trading days ending on the day that is two (2) trading days prior to the applicable date of determination of Fair Market Value; or (B) if the class of Warrant Shares is not listed or admitted to trading on any securities exchange but is regularly traded in any over-the-counter market, then the average of the bid and ask prices per share of the class of Warrant Shares for the ten (10) consecutive trading days ending on the day that is two (2) trading days prior to the applicable date of determination of Fair Market Value; or (C) if the class of Warrant Shares is not traded as described in clauses (A) or (B), then the per share fair market value of the class of Warrant Shares as determined in good faith by the Company’s Board of Directors.

(b) Delivery of Certificates . Certificates for Warrant Shares purchased hereunder shall be transmitted by the transfer agent of the Company to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company (“ DTC ”) through its Deposit Withdrawal Agent Commission system if the Company is a participant in such system and such Warrant Shares are eligible for delivery in such a manner, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise within three Business Days from the delivery to the Company of the Notice of Exercise, surrender of this Warrant and payment of the aggregate Exercise Price as set forth above (the “ Delivery Period ”). This Warrant shall be deemed to have been exercised on the date on which this Warrant is surrendered and payment of the Exercise Price is received by the Company. The Warrant Shares shall be deemed to have been issued, and Holder or any other person so designated to be named therein shall be deemed to have become a holder of record of such shares for all purposes, as of the date on which all of the criteria described in the immediately preceding sentence have occurred, irrespective of the date of delivery of such certificate or certificates, except that, if the date of such surrender and payment is a date when the stock transfer books of the Company are closed, such person shall be deemed to have become the holder of such shares at the close of business on the next succeeding date on which the stock transfer books are open. If fewer than all of the Warrant Shares purchasable under the Warrant are purchased, the Company will, upon such partial exercise, execute and deliver to the Holder a new Warrant (dated as of the Issue Date), in the same form and tenor as this Warrant, evidencing that portion of the Warrant not exercised.

(c) Delivery of Electronic Shares . In lieu of delivering physical certificates representing the Warrant Shares issuable upon exercise (provided that the transfer agent is participating in the DTC Fast Automated Securities Transfer program and provided further that the Holder provides the transfer agent with information required in order to issue such Warrant Shares to the Holder electronically), upon the request of the Holder as set forth in the Notice of Exercise, but only if the Warrant Shares may be issued without restrictive legends, the Company shall cause its transfer agent to electronically transmit, within the Delivery Period, the Warrant Shares issuable upon exercise to the Holder by crediting Holder’s account with DTC through its Deposit Withdrawal Agent Commission system. Any delivery not effected by electronic transmission shall be effected by delivery of physical certificates.

(d) No Fractional Shares . If a fractional share of Warrant Shares would, but for the provisions of this Section 2(d) , be issuable upon exercise of the rights represented by this Warrant, the Company shall (i) round a half share or greater to be delivered to Holder up to the next whole share and (ii) round a less-than-half share to be delivered to Holder down to the nearest whole share.

(e) No Charge to Holder Upon Issuance . The issuance of Warrant Shares upon exercise of this Warrant shall be made without charge to Holder for any issuance tax in respect thereof or other cost incurred by the Company in connection with such exercise and the related issuance of Warrant Shares (other than any transfer taxes resulting from the issuance of Warrant Shares to any person other than Holder).

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(f) Reservation of Shares . During the Exercise Period, the Company shall reserve and keep available out of its authorized but unissued Common Stock such number of Warrant Shares issuable upon the full exercise of this Warrant. All Warrant Shares which are so issuable shall, when issued and upon the payment of the applicable Exercise Price, be duly and validly issued, fully paid and nonassessable and free from all taxes, liens and charges and not subject to the pre-emptive rights of any holder of Common Stock or any other class or series of stock of the Company. During the Exercise Period, the Company shall not take any action which would cause the number of authorized but unissued Common Stock to be less than the number of such shares required to be reserved hereunder for issuance upon exercise of this Warrant.

(g) Limitations on Exercises .

(i) Notwithstanding anything to the contrary contained in this Warrant, this Warrant shall not be exercisable by the Holder hereof to the extent (but only to the extent) that after giving effect to such issuance after exercise, such Holder or any of its affiliates, as a result of such exercise, would beneficially own in excess of 4.99% (the “ Maximum Percentage ”) of the number of shares of Common Stock outstanding immediately after giving effect to such issuance. To the extent the above limitation applies, the determination of whether this Warrant shall be exercisable (vis-à-vis other convertible, exercisable or exchangeable securities owned by the Holder or any of its affiliates) and of which such securities shall be exercisable (as among all such securities owned by the Holder) shall, subject to such Maximum Percentage limitation, be determined on the basis of the first submission to the Company for conversion, exercise or exchange (as the case may be). No prior inability to exercise this Warrant pursuant to this paragraph shall have any effect on the applicability of the provisions of this paragraph with respect to any subsequent determination of exercisability. For the purposes of this paragraph, beneficial ownership and all determinations and calculations (including, without limitation, with respect to calculations of percentage ownership) shall be determined in accordance with Section 13(d) of the Exchange Act. The limitations contained in this paragraph shall apply to a successor Holder of this Warrant. For any reason at any time, upon the written or oral request of the Holder, the Company shall within one (1) Business Day confirm orally and in writing to the Holder the number of shares of Common Stock then outstanding, including by virtue of any prior conversion or exercise of convertible or exercisable securities into Common Stock. The provisions of this Section 2(g)(i) may be waived by such Holder, at the election of such Holder, upon not less than 61 days’ prior notice to the Company, and the provisions of this Section 2(g)(i) shall continue to apply until such 61st day (or such later date, as determined by such Holder, as may be specified in such notice of waiver). At 12:00 a.m., New York Time, on the 62 ^nd day following the provision of the notice referred to in the preceding sentence, the exercise limitation set forth above shall expire.

3. Adjustments in Certain Events . The number, class, and price of Warrant Shares for which this Warrant may be exercised are subject to adjustment from time to time upon the happening of certain events as follows:

(a) Subdivisions, Combinations and Other Issuances . If the outstanding shares of the Company’s Common Stock are divided into a greater number of shares, by forward stock split or otherwise, or a dividend in stock is paid on the Common Stock, then the number of shares of Warrant Shares for which the Warrant is then exercisable will be proportionately increased and the Exercise Price will be proportionately reduced. Conversely, if the outstanding shares of Common Stock are combined into a smaller number of shares of Common Stock, by reverse stock split or otherwise, then the number of Warrant Shares for which the Warrant is then exercisable will be proportionately reduced and the Exercise Price will be proportionately increased. The increases and reductions provided for in this Section 3(a) will be made with the intent and, as nearly as practicable, the effect that neither the percentage of the total equity of the Company obtainable on exercise of the Warrants nor the price payable for such percentage upon such exercise will be affected by any event described in this Section 3(a) .

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(b) Merger, Consolidation, Reclassification, Reorganization, Etc . In case of any change in the Common Stock through merger, consolidation, reclassification, reorganization, partial or complete liquidation, purchase of all or substantially all the assets of the Company, or other change in the capital structure of the Company, then, as a condition of such change, lawful and adequate provision will be made so that the Holder will have the right thereafter to receive upon the exercise of the Warrant the kind and amount of shares of stock or other securities or property to which he would have been entitled if, immediately prior to such event, he had held the number of Warrant Shares obtainable upon the exercise of the Warrant. In any such case, appropriate adjustment will be made in the application of the provisions set forth herein with respect to the rights and interest thereafter of the Holder, to the end that the provisions set forth herein will thereafter be applicable, as nearly as reasonably may be, in relation to any shares of stock or other property thereafter deliverable upon the exercise of the Warrant. The Company will not permit any change in its capital structure to occur unless the issuer of the shares of stock or other securities to be received by the Holder, if not the Company, agrees to be bound by and comply with the provisions of this Warrant.

(c) If securities of the Company or securities of any subsidiary of the Company are distributed pro rata to holders of Common Stock, such number of securities will be distributed to the Holder or its assignee upon exercise of its rights hereunder as such Holder or assignee would have been entitled to if this Warrant had been exercised prior to the record date for such distribution. The provisions with respect to adjustment of the Common Stock provided in this Section 3 will also apply to the securities to which the Holder or its assignee is entitled under this Section 3(c) .

4. No Rights as a Stockholder . Nothing contained in this Agreement shall be construed as conferring upon the Holder any rights whatsoever as a stockholder of the Company, either at law or in equity, including without limitation, or Holders the right to vote or to consent or to receive notice as a stockholder in respect of any meetings of stockholders for the election of directors the right to receive dividends or any other matter.

5. Restrictions on Transfer; Legends .

(a) Registration or Exemption Required . Assuming the accuracy of the representations and warranties of the Holder contained in herein, this Warrant has been issued in a transaction exempt from the registration requirements of the Securities Act by virtue of Section 4(a)(2) of the Securities Act and Regulation D promulgated thereunder and exempt from state registration or qualification under applicable state laws. The Holder acknowledges that he has been advised by the Company that this Warrant and the Warrant Shares issuable upon exercise thereof have not been registered under the Securities Act. Neither this Warrant nor the Warrant Shares may be pledged, transferred, sold or assigned except pursuant to an effective registration statement or an exemption to the registration requirements of the Securities Act and applicable state laws. If, at the time of the surrender of this Warrant in connection with any transfer of this Warrant, the transfer of this Warrant shall not be registered pursuant to an effective registration statement under the Securities Act and under applicable state securities or blue sky laws, the Company may require, as a condition of allowing such transfer (i) that the Holder or transferee of this Warrant, as the case may be, furnish to the Company a written opinion of counsel (which opinion shall be in form, substance and scope customary for opinions of counsel in comparable transactions) to the effect that such transfer may be made without registration under the Securities Act and under applicable state securities or blue sky laws, (ii) that the holder or transferee execute and deliver to the Company an investment letter in form and substance acceptable to the Company and (iii) that the transferee be an “accredited investor” as defined in Rule 501(a) promulgated under the Securities Act or a “qualified institutional buyer” as defined in Rule 144A(a) under the Securities Act.

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(b) Representations of Holder . The Holder represents and warrants that he has acquired this Warrant and will acquire the Warrant Shares for his own account for investment and not with a view to the sale or distribution thereof or the granting of any participation therein, and that he has no present intention of distributing or selling to others any of such interest or granting any participation therein. The Holder acknowledges that the Warrant and Warrant Shares must be held indefinitely unless a subsequent disposition thereof is registered under the Securities Act or registered or qualified under any applicable state securities or “blue-sky” laws or is exempt from registration and/or qualification. The Holder has no need for liquidity in its investment in the Company, and is able to bear the economic risk of such investment for an indefinite period and to afford a complete loss thereof. The Holder is an “accredited investor” as such term is defined in Rule 501 (the provisions of which are known to the Holder) promulgated under the Act.

(c) Restrictive Legend . The Holder understands that until such time as the Warrant Shares have been registered under the Securities Act, or otherwise may be sold pursuant to Rule 144 under the Securities Act or an exemption from registration under the Securities Act without any restriction as to the number of securities as of a particular date that can then be immediately sold, this Warrant and the Warrant Shares, as applicable, shall bear a restrictive legend in substantially the form set forth on the cover page of this Warrant (and a stop-transfer order may be placed against transfer of the certificates for such securities).

(d) Disposition of Warrant or Warrant Shares . With respect to any offer, sale or other disposition of this Warrant or any Warrant Shares prior to registration of such Warrant Shares, the Holder agrees to give written notice to the Company prior thereto, describing briefly the manner thereof, together with evidence, reasonably satisfactory to the Company (which shall include such representation of the transferee regarding investment intent as the Company may request, to the effect that such offer, sale or other disposition may be effected without registration or qualification (under the Act as then in effect or any federal or state securities law then in effect) of this Warrant or such Warrant Shares and indicating whether or not under the Securities Act certificates for this Warrant or Warrant Shares to be sold or otherwise disposed of require any restrictive legend as to applicable restrictions on transferability in order to ensure compliance with such law. Upon receiving such written notice and reasonably satisfactory evidence, the Company, as promptly as practicable but no later than seven (7) days after receipt of the written notice, shall notify the Holder that the Holder may sell or otherwise dispose of this Warrant or Warrant Shares, all in accordance with the terms of the notice delivered to the Company. If the Company determines that the evidence is not reasonably satisfactory to the Company, the Company shall so notify the Holder promptly with details thereof after such determination has been made. Notwithstanding the foregoing, any Warrant Shares may be offered, sold or otherwise disposed of in accordance with Rule 144 under the Act and in compliance with the applicable statutory resale restrictions imposed by state securities laws, provided that the Company shall have been furnished with such information as the Company may reasonably request to provide a reasonable assurance that the provisions of Rule 144 and the applicable resale restrictions imposed by state securities laws have been satisfied. Each certificate representing this Warrant or the Warrant Shares thus transferred shall bear a legend as to the applicable restrictions on transferability in order to ensure compliance with such laws, unless pursuant to an opinion of counsel for the Holder, such legend is not required in order to ensure compliance with such laws. The Company may issue stop transfer instructions to its transfer agent in connection with such restrictions.

(e) Removal of Restrictive Legends . The certificates evidencing the Warrant Shares shall not contain any legend restricting the transfer thereof: (A) while a registration statement covering the sale or resale of the Warrant Shares is effective under the Securities Act and such legend removal is permitted

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under applicable securities laws (including compliance with the prospectus delivery requirements of the Securities Act), or (B) following any sale of such Warrant Shares pursuant to Rule 144, or (C) if such Warrant Shares are eligible for sale under Rule 144(b)(1), or (D) if such legend is not required under applicable requirements of the Securities Act (including judicial interpretations and pronouncements issued by the staff of the Commission) and the Company shall have received an opinion of counsel to the Holder in form reasonably acceptable to the Company to such effect (collectively, the “ Unrestricted Conditions ”). The Company shall cause its counsel to issue a legal opinion to its transfer agent if required by the transfer agent to effect the issuance of the Warrant Shares, as applicable, without a restrictive legend or removal of the legend hereunder. The Company agrees that at such time as the Unrestricted Conditions are met, it will, no later than three (3) Trading Days following the delivery by the Holder to the Company or the transfer agent of a certificate representing Warrant Shares, issued with a restrictive legend, deliver or cause to be delivered to such Holder a certificate (or electronic transfer) representing such Warrant Shares that is free from all restrictive and other legends.

6. Notices; Adjustments .

(i) All notices required or permitted hereunder shall be in writing and shall be deemed effectively given: (i) upon personal delivery to the party to be notified; (ii) when sent by confirmed electronic mail or facsimile if sent during normal business hours of the recipient, and if not, then on the next business day; (iii) two (2) Business Days after having been sent by registered or certified mail, return receipt requested, postage prepaid; or (iv) one (1) Business Day after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt. All communications shall be sent to the Company or to Holder, as applicable, at the respective addresses set forth on the signature page to the Purchase Agreement or at such other address(es) as they may designate, respectively, by ten (10) days advance written notice to the other party hereto.

(ii) Upon the occurrence of any adjustments pursuant to Sections 3(a) or 3(c) hereof, the Company at its expense shall, as promptly as reasonably practicable but in any event not later than 10 days thereafter, compute such adjustment in accordance with the terms hereof and furnish to Holder a certificate setting forth such adjustment and showing in detail the facts upon which such adjustment is based. In the event of any taking by the Company of a record of the holders of any class of securities for the purpose of determining the holders thereof who are entitled to receive any dividend or other distribution, the Company shall mail to the Holder, at least ten (10) days prior to the date on which any such record is to be taken for the purpose of such dividend or distribution, a notice specifying such date. In the event of any voluntary dissolution, liquidation or winding up of the Company, the Company shall mail to the Holder, at least ten (10) days prior to the date of the occurrence of any such event, a notice specifying such date. If the approval of any stockholders of the Company shall be required in connection with any transaction contemplated by Section 3(b) above, then, the Company shall cause to be mailed to the Holder at least 10 calendar days prior to the applicable record or effective date hereinafter specified, a notice stating the date on which such transaction is expected to become effective or close, and the date as of which it is expected that holders of the Common Stock of record shall be entitled to exchange their shares of the Common Stock for securities, cash or other property deliverable upon such transaction. Notwithstanding the immediately preceding sentences, however, if the date on which the Company is obliged to provide notice hereunder to the Holders is prior to a public announcement relating to the events set forth and on such date the Company’s securities are traded or quoted on any recognized national securities exchange or quotation system, then such notice shall be provided to each Holder simultaneously with the notice provided to the Company’s common stockholders. Failure to give such notice, or any defect therein, shall not, however, affect the legality or validity of any such action.

7. Non-Circumvention . The Company hereby covenants and agrees that the Company will not, by amendment of its certificate of incorporation, bylaws or through any reorganization, transfer of assets,

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consolidation, merger, scheme of arrangement, dissolution, issue or sale of securities, or any other action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, and will at all times in good faith carry out all the provisions of this Warrant and take all action as may be reasonably required to protect the rights of the Holder.

8. Governing Law . This Warrant shall be governed by and construed in accordance with the laws of the State of New York, without regard to conflict of law principles, and notwithstanding the fact that one or more counterparts hereof may be executed outside of the state, or one or more of the obligations of the parties hereunder are to be performed outside of the state.

9. Loss, Theft, Destruction or Mutilation of Warrant . Upon receipt by the Company of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant, and, in the case of loss, theft, or destruction, of indemnity reasonably satisfactory to it, and, if mutilated, upon surrender and cancellation of this Warrant, the Company will execute and deliver a new Warrant, having terms and conditions identical to this Warrant, in lieu hereof.

10. Modification and Waiver of Warrants . Any term of this Warrant may be amended, waived, discharged or terminated (either generally or in a particular instance and either retroactively or prospectively) with the written consent of the Company and the holders of the Warrants representing at least 50.1% of the number of shares of Common Stock then subject to outstanding Warrants issued pursuant to the Purchase Agreement. Notwithstanding the foregoing, (a) this Warrant may be amended and the observance of any term hereunder may be waived without the written consent of the Holder only in a manner which applies to all Warrants issued pursuant to the Purchase Agreement in the same fashion and (b) other than in connection with a transaction contemplated by Section 3 of this Warrant, the number of Warrant Shares subject to this Warrant and the Exercise Price of this Warrant may not be amended, and the right to exercise this Warrant may not be waived, without the written consent of the Holder. The Company shall give prompt written notice to the Holder of any amendment hereof or waiver hereunder that was effected without the Holder’s written consent. No waivers of any term, condition or provision of this Warrant, in any one or more instances, shall be deemed to be, or construed as, a further or continuing waiver of any such term, condition or provision.

11. Successors . This Warrant shall be binding and inure to the benefit of the parties and their respective successors and assigns hereunder; provided that this Warrant may be assigned by Holder only in compliance with the conditions specified in and in accordance with all of the terms of this Warrant. This Warrant does not create and shall not be construed as creating any rights enforceable by any other person or corporation.

12. Headings . The headings used in this Warrant are used for convenience only and are not to be considered in construing or interpreting this Warrant.

13. Saturdays, Sundays, Holidays . If the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall be a Saturday or a Sunday or shall be a legal holiday in the State of New York, then such action may be taken or such right may be exercised on the next succeeding day not a legal holiday.

14. Severability . If any provision of this Warrant shall be held to be invalid or unenforceable, such invalidity or unenforceability shall not affect any other provisions of this Warrant.

15. Execution and Counterparts . This Warrant may be executed in any number of counterparts, each of which when so executed and delivered shall be deemed an original, and such counterparts together shall constitute only one instrument. Any one of such counterparts shall be sufficient for the purpose of proving the existence and terms of this Warrant, and no party shall be required to produce an original or all of such counterparts in making such proof.

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16. Acceptance . Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

Signature page to Common Stock Purchase Warrant follows.

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IN WITNESS WHEREOF, the Company has caused this Common Stock Purchase Warrant to be executed and delivered as of the Issue Date by an officer thereunto duly authorized.

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ATTACHMENT I

NOTICE OF EXERCISE

The undersigned hereby elects to purchase, pursuant to the provisions of the Common Stock Warrant issued by Authentidate Holding Corp. as of February 17, 2015, and held by the undersigned, the original of which is attached hereto, and (check the applicable box):

X = Y (A-B)/A

(            ) = (            ) [(            ) - (            )]/(            )

Information for Delivery of uncertificated Shares by DWAC:

¨ If this box is checked, the Holder requests delivery of physical certificates representing the Warrant Shares and requests that such certificates be delivered to the following address:

If such number of shares shall not be all the shares purchasable upon the exercise of the Warrants evidenced by this Warrant, a new warrant certificate for the balance of such Warrants remaining unexercised shall be registered in the name of and delivered to:

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ATTACHMENT II

[FORM OF ASSIGNMENT]

(To be executed by the registered holder if such holder

desires to transfer the Warrant Certificate.)

FOR VALUE RECEIVED, the undersigned Holder of this Warrant hereby sells, assigns and transfers the foregoing Warrant and all rights evidenced thereby to

and does hereby irrevocably constitute and appoint                     , Attorney, to transfer the within Warrant Certificate on the books of Authentidate Holding Corp., Inc., with full power of substitution.

NOTE: The signature to this Assignment Form must correspond with the name as it appears on the face of the Warrant, without alteration or enlargement or any change whatever. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Warrant.

On this      day of             , before me personally came             , to me known, who being by me duly sworn, did depose and say that he resides at                     , that he is the holder of the foregoing instrument and that he executed such instrument and duly acknowledged to me that he executed the same.

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