Exhibit 4.28 Execution Version NEITHER THIS NOTE
NOR THE SECURITIES INTO WHICH THIS NOTE IS CONVERTIBLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE. THESE SECURITIES HAVE BEEN SOLD IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER
THE SECURITIES ACT OF 1933, AS AMENDED (THE SECURITIES ACT), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM,
OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS. SMX (SECURITY MATTERS) PUBLIC LIMITED COMPANY CONVERTIBLE PROMISSORY NOTE Original Principal Amount:$1,500,000 Issuance Date:
March 9, 2023 Number: SMX-1 FOR VALUE RECEIVED, SMX (SECURITY MATTERS) PUBLIC LIMITED COMPANY, an public limited company organized under the laws of Ireland (the
Company), hereby promises to pay to the order of YA II PN, LTD., or its registered assigns (the Holder), the amount set out above as the Original Principal Amount (as reduced pursuant to the terms hereof
pursuant to repayment, redemption, conversion or otherwise, the Principal) and Payment Premium, in each case when due, and to pay interest (Interest) on any outstanding Principal at the applicable Interest Rate
(as defined below) from the date set out above as the Issuance Date (the Issuance Date) until the same becomes due and payable, whether upon the Maturity Date or acceleration, conversion, redemption or otherwise (in each case in
accordance with the terms hereof). Certain capitalized terms used herein are defined in Section (13). The Issuance Date is the date of the first issuance of this Convertible Promissory Note (the Note) regardless of the number of
transfers and regardless of the number of instruments, which may be issued to evidence such Note. This Note was issued with an 8% original issue discount. This Note is being issued pursuant to Section 3.01 of the Reciprocal Standby Equity Purchase Agreement, dated February 23, 2023 (as
may be amended, amended and restated, extended, supplemented or otherwise modified in writing from time to time, the SEPA), between the Company and the Investor. (1) GENERAL TERMS (a)
Maturity Date. On the Maturity Date, the Company shall pay to the Holder an amount in cash representing all outstanding Principal, plus the Payment Premium (if applicable), accrued and unpaid Interest, and any other amounts outstanding
pursuant to the terms of this Note. The Maturity Date shall be March 9, 2024, as may be extended at the option of the Holder. Other than as specifically permitted by this Note, the Company may not prepay or redeem any portion
of the outstanding Principal and accrued and unpaid Interest




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(b) Interest Rate and Payment of Interest. Interest shall accrue on the outstanding
Principal balance hereof at an annual rate equal to 0% (Interest Rate), which Interest Rate shall increase to an annual rate of 15% upon an Event of Default for so long as it remains uncured. Interest shall be calculated based on
a 365-day year and the actual number of days elapsed, to the extent permitted by applicable law. (c) Monthly Payments. If, any time after the Issuance Date set forth above, and from time to time thereafter, a Trigger Event occurs,
then the Company shall make monthly payments beginning on the 10th Trading Days after the Trigger Date and continuing on the same day of each successive Calendar Month. Each monthly payment shall be in an amount equal to the sum of (i) $500,000 of
Principal in the aggregate among this Note and all Other Notes (or the outstanding Principal if less than such amount) (the Triggered Principal Amount), plus (ii) the Payment Premium (as defined below) in respect of such
Triggered Principal Amount, and (iii) accrued and unpaid interest hereunder as of each payment date. The obligation of the Company to make monthly prepayments hereunder shall cease (with respect to any payment that has not yet come due) if any
time after the Trigger Date (A) the daily VWAP is greater than the 110% of the Floor Price a period of 5 consecutive Trading Days in the event of a Floor Price Trigger, or (B) the date the Company has obtained stockholder approval to
increase the number of Common Stock under the Exchange Cap and/ or the Exchange Cap no longer applies, in the event of an Exchange Cap Trigger, unless a subsequent Trigger Event occurs. (d) Optional Redemption. The Company at its option shall have the right, but not the obligation, to redeem (Optional
Redemption) early a portion or all amounts outstanding under this Note as described in this Section; provided that (i) the trading price of the Common Stock is less than the Fixed Price and (ii) the Company provides the
Holder with at least 5 Business Days prior written notice (each, a Redemption Notice) of its desire to exercise an Optional Redemption. Each Redemption Notice shall be irrevocable and shall specify the outstanding balance of
the Note to be redeemed and the Redemption Amount. The Redemption Amount shall be equal to the outstanding Principal balance being redeemed by the Company, plus the Payment Premium, plus all accrued and unpaid interest. After
receipt of the Redemption Notice, the Holder shall have 5 Business Days to elect to convert all or any portion of the Note. On the 6th Business Day after the Redemption Notice, the Company shall deliver to the Holder the Redemption Amount with
respect to the Principal amount redeemed after giving effect to conversions effected during the 5 Business Day period. (e) Payment
Dates. Whenever any payment or other obligation hereunder shall be due on a day other than a Business Day, such payment shall be made on the next succeeding Business Day. (2) EVENTS OF DEFAULT. (a) An Event of Default, wherever used herein, means any one of the following events (whatever the reason and whether it
shall be voluntary or involuntary or effected by operation of law or pursuant to any judgment, decree or order of any court, or any order, rule or regulation of any administrative or governmental body):  2




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(i) the Companys failure to pay to the Holder any amount of Principal, Payment
Premium, Interest, or other amounts when and as due under this Note or any other Transaction Document within five (5) Business Days after such payment is due; (ii) The Company or any Subsidiary of the Company shall commence, or there shall be commenced against the Company or any Subsidiary of the
Company under any applicable bankruptcy or insolvency laws as now or hereafter in effect or any successor thereto, or the Company or any Subsidiary of the Company commences any other proceeding under any reorganization, arrangement, adjustment of
debt, relief of debtors, dissolution, insolvency or liquidation or similar law of any jurisdiction whether now or hereafter in effect relating to the Company or any Subsidiary of the Company any such bankruptcy, insolvency or other proceeding which
remains undismissed for a period of sixty one (61) days; or the Company or any Subsidiary of the Company is adjudicated insolvent or bankrupt; or any order of relief or other order approving any such case or proceeding is entered; or the
Company or any Subsidiary of the Company suffers any appointment of any custodian, private or court appointed receiver or the like for it or all or substantially all of its property which continues undischarged or unstayed for a period of sixty one
(61) days; or the Company or any Subsidiary of the Company makes a general assignment of all or substantially all of its assets for the benefit of creditors; or the Company or any Subsidiary of the Company shall fail to pay, or shall state that
it is unable to pay, or shall be unable to pay, its debts generally as they become due; or the Company or any Subsidiary of the Company shall call a meeting of its creditors with a view to arranging a composition, adjustment or restructuring of its
debts; or the Company or any Subsidiary of the Company shall by any act or failure to act expressly indicate its consent to, approval of or acquiescence in any of the foregoing; or any corporate or other action is taken by the Company or any
Subsidiary of the Company for the purpose of effecting any of the foregoing; (iii) The Company or any Subsidiary of the Company shall
default in any of its obligations under any debenture, mortgage, credit agreement or other facility, indenture agreement, factoring agreement or other instrument under which there may be issued, or by which there may be secured or evidenced any
indebtedness for borrowed money or money due under any long term leasing or factoring arrangement of the Company or any Subsidiary of the Company in an amount exceeding $3,000,000, whether such indebtedness now exists or shall hereafter be created
and such default is not cured within the time prescribed by the documents governing such indebtedness or if no time is prescribed within ten (10) Business Days (excluding, for the avoidance of doubt, payables to vendors in the ordinary course
of business); (iv) The Common Stock shall cease to be quoted or listed for trading, as applicable, on any Primary Market for a period of
ten (10) consecutive Trading Days; (v) The Company or any Subsidiary of the Company shall be a party to any Change of Control
Transaction (as defined in Section (12)) unless in connection with such Change of Control Transaction this Note is retired;  3




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(vi) the Companys (A) failure to deliver the required number of shares of Common
Stock to the Holder within two (2) Trading Days after the applicable Share Delivery Date or (B) notice, written or oral, to any holder of the Note, including by way of public announcement, at any time, of its intention not to comply with a
request for conversion of any Note into shares of Common Stock that is tendered in accordance with the provisions of the Note; (vii) The
Company shall fail for any reason to deliver the payment in cash pursuant to a Buy-In (as defined herein) within five (5) Business Days after such payment is due; (viii) The Companys failure to timely file with the Commission any Periodic Report on or before the due date of such filing as
established by the Commission, it being understood, for the avoidance of doubt, that due date includes any permitted filing deadline extension under Rule 12b-25 under the Exchange Act; (ix) Any material provision of any Transaction Document, at any time after its execution and delivery and for any reason other than as
expressly permitted hereunder or thereunder, ceases to be in full force and effect; or the Company denies in writing that it has any or further liability or obligation under any Transaction Document, or purports in writing to revoke, terminate
(other than in line with the relevant termination provisions) or rescind any Transaction Document; (x) Any representation or warranty
made or deemed to be made by the Company in any Transaction Document shall prove to have been incorrect in any material respect (or, in the case of any such representation or warranty already qualified by materiality, such representation or warranty
shall prove to have been incorrect) when made or deemed made; (xi) Any Event of Default (as defined in the Other Notes or in any
Transaction Document other than this Note) occurs with respect to any Other Notes held by the Holder; or (xii) The Company shall fail to
observe or perform any material covenant, agreement or warranty contained in, or otherwise commit any material breach or default of any provision of this Note (except as may be covered by Section (2)(a)(i) through (2)(a)(xii) hereof) or any
Transaction Document, which is not cured within the time prescribed or if no time is prescribed within ten (10) Business Days. (b)
During the time that any portion of this Note is outstanding, if any Event of Default has occurred (other than an event with respect to the Company described in Section (2)(a)(ii)), the full unpaid Principal amount of this Note, together with
interest and other amounts owing in respect thereof, to the date of acceleration shall become at the Holders election given by notice pursuant to Section (5), immediately due and payable in cash; provided that, in the case of any event with
respect to the Company described in Section (2)(a)(ii), the full unpaid Principal amount of this Note, together with interest and other amounts owing in respect thereof to the date of acceleration, shall automatically become due and payable, in each
case without presentment, demand, protest or other notice of any kind, all of which are hereby waived by the Company. Furthermore, in addition to any other remedies, the Holder shall have the right (but not the  4




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obligation) to convert, on one or more occasions all or part of the Note in accordance with Section (3) (and subject to the limitations set out in Section (3)(c)(i) and Section (3)(c)(ii)) at any
time after (x) an Event of Default (provided that such Event of Default is continuing) or (y) the Maturity Date at the Conversion Price. The Holder need not provide and the Company hereby waives any presentment, demand, protest or other
notice of any kind, (other than required notice of conversion) and the Holder may immediately enforce any and all of its rights and remedies hereunder and all other remedies available to it under applicable law. Such declaration may be rescinded and
annulled by the Holder in writing at any time prior to payment hereunder. No such rescission or annulment shall affect any subsequent Event of Default or impair any right consequent thereon. (3) CONVERSION OF NOTE. This Note shall be convertible into shares of the Companys Common Stock, on the terms and conditions set
forth in this Section (3). (a) Conversion Right. Subject to the limitations of Section (3)(c), at any time or times on or after
the Issuance Date, the Holder shall be entitled to convert any portion of the outstanding and unpaid Conversion Amount into fully paid and nonassessable shares of Common Stock in accordance with Section (3)(b), at the Conversion Price. The number of
shares of Common Stock issuable upon conversion of any Conversion Amount pursuant to this Section (3)(a) shall be determined by dividing (x) such Conversion Amount by (y) the Conversion Price. The Company shall not issue any fraction of a
share of Common Stock upon any conversion. All calculations under this Section (3) shall be rounded to the nearest $0.0001. If the issuance would result in the issuance of a fraction of a share of Common Stock, the Company shall round such
fraction of a share of Common Stock up to the nearest whole share. The Company shall pay any and all transfer, stamp and similar taxes that may be payable with respect to the issuance and delivery of Common Stock upon conversion of any Conversion
Amount. (b) Mechanics of Conversion. (i) Optional Conversion. To convert any Conversion Amount into shares of Common Stock on any date (a Conversion
Date), the Holder shall (A) transmit by email (or otherwise deliver), for receipt on or prior to 11:59 p.m., New York Time, on such date, a copy of an executed notice of conversion in the form attached hereto as Exhibit I (the
Conversion Notice) to the Company and (B) if required by Section (3)(b)(iii), surrender this Note to a nationally recognized overnight delivery service for delivery to the Company (or an indemnification undertaking reasonably
satisfactory to the Company with respect to this Note in the case of its loss, theft or destruction). On or before the third (3rd) Trading Day following the date of receipt of a Conversion Notice
(the Share DeliveryDate), the Company shall (X) if legends are not required to be placed on certificates of Common Stock and provided that the Transfer Agent is participating in the Depository Trust
Companys (DTC) Fast Automated Securities Transfer Program, credit such aggregate number of shares of Common Stock to which the Holder shall be entitled to the Holders or its designees balance account with DTC
through its Deposit Withdrawal Agent Commission system or (Y) if the Transfer Agent is not participating in the DTC Fast Automated Securities Transfer Program, issue and deliver to the address as specified in the Conversion Notice, a
certificate, registered in the name of the Holder or its designee, for the number of shares of Common Stock to which the Holder shall be entitled which certificates shall not bear any restrictive legends unless required pursuant to rules and
regulations of the Commission. If this Note is physically surrendered for conversion and the outstanding Principal  5




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of this Note is greater than the Principal portion of the Conversion Amount being converted, then the Company shall as soon as practicable and in no event later than three (3) Business Days
after receipt of this Note and at its own expense, issue and deliver to the holder a new Note representing the outstanding Principal not converted. The Person or Persons entitled to receive the shares of Common Stock issuable upon a conversion of
this Note shall be treated for all purposes as the record holder or holders of such shares of Common Stock upon the transmission of a Conversion Notice. (ii) Companys Failure to Timely Convert. If within three (3) Trading Days after the Companys receipt of an email copy
of a Conversion Notice the Company shall fail to issue and deliver a certificate to the Holder or credit the Holders balance account with DTC for the number of shares of Common Stock to which the Holder is entitled upon such holders
conversion of any Conversion Amount (a Conversion Failure), and if on or after such Trading Day the Holder purchases (in an open market transaction or otherwise) Common Stock to deliver in satisfaction of a sale by the Holder of
Common Stock issuable upon such conversion that the Holder anticipated receiving from the Company (a Buy-In), then the Company shall, within three (3) Business Days after the
Holders request and in the Holders discretion, either (i) pay cash to the Holder in an amount equal to the Holders total purchase price (including brokerage commissions and other out of pocket expenses, if any) for the shares
of Common Stock so purchased (the Buy-In Price), at which point the Companys obligation to deliver such certificate (and to issue such Common Stock) shall terminate, or
(ii) promptly honor its obligation to deliver to the Holder a certificate or certificates representing such Common Stock and pay cash to the Holder in an amount equal to the excess (if any) of the Buy-In
Price over the product of (A) such number of shares of Common Stock, times (B) the Closing Price on the Conversion Date. (iii)
Book-Entry. Notwithstanding anything to the contrary set forth herein, upon conversion of any portion of this Note in accordance with the terms hereof, the Holder shall not be required to physically surrender this Note to the Company unless
(A) the full Conversion Amount represented by this Note is being converted or (B) the Holder has provided the Company with prior written notice (which notice may be included in a Conversion Notice) requesting reissuance of this Note upon
physical surrender of this Note. The Holder and the Company shall maintain records showing the Principal and Interest converted and the dates of such conversions or shall use such other method, reasonably satisfactory to the Holder and the Company,
so as not to require physical surrender of this Note upon conversion. (c) Limitations on Conversions. (i) Beneficial Ownership. The Holder shall not have the right to convert any portion of this Note to the extent that after giving
effect to such conversion, the Holder, together with any affiliate thereof, would beneficially own (as determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder) in excess of 4.99% of the number of
shares of Common Stock outstanding immediately after giving effect to such conversion or receipt of shares as payment of interest. Since the Holder will not be obligated to report to the Company the number of shares of Common Stock it may hold at
the time of a conversion hereunder, unless the conversion at issue would result in the issuance of shares of Common Stock in excess of 4.99% of the then outstanding shares of Common Stock without regard to any other shares which may be beneficially
owned by the Holder or an affiliate thereof,  6




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the Holder shall have the authority and obligation to determine whether the restriction contained in this Section will limit any particular conversion hereunder and to the extent that the Holder
determines that the limitation contained in this Section applies, the determination of which portion of the Principal amount of this Note is convertible shall be the responsibility and obligation of the Holder. The provisions of this Section may be
waived by a Holder (but only as to itself and not to any other Holder) upon not less than 65 days prior notice to the Company. Other Holders shall be unaffected by any such waiver. (ii) Principal Market Limitation. Notwithstanding anything in this Note to the contrary, the Company shall not issue any shares of
Common Stock upon conversion of this Note, or otherwise, if the issuance of such Common Stock, together with any Common Stock issued in connection the SEPA and with any other related transactions that may be considered part of the same series of
transactions, would exceed the aggregate number of shares of Common Stock that the Company may issue in a transaction in compliance with the Companys obligations under the rules or regulations of Nasdaq Stock Market LLC (the
Nasdaq) and shall be referred to as the Exchange Cap, except that such limitation shall not apply if the Companys stockholders have approved such issuances on such terms in excess of the Exchange Cap in
accordance with the rules of the Nasdaq. (iii) Other Conversion Limitations. The Holder agrees that, except as set forth below,
it shall not convert more than an aggregate of $500,000 of Conversion Amount of this Note and any Other Notes held by the Holder in any consecutive 30-day period. The limitations agreed by the Holder in this
section shall not apply (i) at any time upon the occurrence and during the continuance of an Event of Default, and (ii) with respect to any conversions where the Conversion Price is greater than or equal to the Fixed Price.
This limitation may be waived with the consent of the Company. (d) Other Provisions. (i) The execution, delivery and performance of this Note by the Company and the consummation by the Company of the transactions contemplated
hereby (including, without limitation, the Payments hereunder) (i) will not result in a violation of the articles of incorporation or other organizational documents of the Company or its Subsidiaries, (ii) are not prevented or prohibited
by or under any agreement, indenture or instrument to which the Company or its Subsidiaries is a party, (iii) will not conflict with, or constitute a default (or an event which with notice or lapse of time or both would become a default) under,
or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which the Company or its Subsidiaries is a party, (iv) result in a violation of any law, rule, regulation, order,
judgment or decree (including federal and state securities laws and regulations) applicable to the Company or its Subsidiaries or by which any property or asset of the Company or its Subsidiaries is bound or affected except, in the case of clauses
(ii), (iii) or (iv) above, to the extent such violations that would not reasonably be expected to have a Material Adverse Effect. (ii) All calculations under this Section (4) shall be rounded to the nearest $0.0001 or whole share.  7




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(iii) (ii) The Company shall at all times reserve and keep available out of its authorized
Common Stock the full number of shares of Common Stock issuable upon conversion of all outstanding amounts under this Note (the Required Reserve Amount), and within three (3) Business Days following the receipt by the Company
of a Holders notice that such Required Reserve Amount is not so reserved or insufficient, the Company shall promptly reserve a sufficient number of shares of Common Stock to comply with such requirement. If at any time the number of authorized
but unissued Common Stock is less than the Required Reserve Amount, the Company will promptly take all corporate action necessary to propose to its general meeting of shareholders an increase of its authorized share capital necessary to meet the
Companys obligations pursuant to this Note, recommending that shareholders vote in favor of such an increase. If at any time the number of shares of Common Stock that remain available for issuance under the Exchange Cap is less than 100% of
the maximum number of shares issuable upon conversion of all the Notes and Other Notes then outstanding (assuming for purposes hereof that (x) the Notes are convertible at the Conversion Price then in effect, and (y) any such conversion
shall not take into account any limitations on the conversion of the Note, other than the Floor Price), the Company will use commercially reasonable efforts to promptly call and hold a shareholder meeting for the purpose of seeking the approval of
its shareholders as required by the applicable rules of the Principal Market, for issuances of shares in excess of the Exchange Cap. Nothing herein shall limit a Holders right to pursue actual damages or declare an Event of Default pursuant to
Section (2) herein for the Companys failure to deliver certificates representing shares of Common Stock upon conversion within the period specified herein and such Holder shall have the right to pursue all remedies available to it at law
or in equity including, without limitation, a decree of specific performance and/or injunctive relief, in each case without the need to post a bond or provide other security. The exercise of any such rights shall not prohibit the Holder from seeking
to enforce damages pursuant to any other Section hereof or under applicable law. (iv) Legal Opinions. The Company is obligated to
cause its legal counsel to deliver legal opinions to the Companys transfer agent in connection with any legend removal upon the expiration of any holding period or other requirement for which the Underlying Shares may bear legends restricting
the transfer thereof. To the extent that are not provided (either timely or at all), then, in addition to being an Event of Default hereunder, the Company agrees to reimburse the Holder for all reasonable costs incurred by the Holder in connection
with any legal opinions paid for by the Holder in connection with sale or transfer of Underlying Shares of Common Stock. The Holder shall notify the Company of any such costs and expenses it incurs that are referred to in this section from time to
time and all amounts owed hereunder shall be paid by the Company with reasonable promptness. (e) Adjustment of Conversion Price upon
Subdivision or Combination of Common Stock. If the Company, at any time while this Note is outstanding, shall (a) pay a stock dividend or otherwise make a distribution or distributions on shares of its Common Stock or any other equity or
equity equivalent securities payable in shares of Common Stock, (b) subdivide outstanding shares of Common Stock into a larger number of shares, (c) combine (including by way of reverse stock split) outstanding shares of Common Stock into
a smaller number of shares, or (d) issue by reclassification of shares of the Common Stock any shares of capital stock of the Company, then each of the Fixed Price and the Floor Price shall be multiplied by a fraction of which the numerator
shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding before such event and of which the denominator shall be the number of shares of Common Stock outstanding after such event. Any adjustment made pursuant to
this Section shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a
subdivision, combination or re-classification.  8




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(f) Other Corporate Events. In addition to and not in substitution for any other
rights hereunder, prior to the consummation of any Fundamental Transaction pursuant to which holders of shares of Common Stock are entitled to receive securities or other assets with respect to or in exchange for shares of Common Stock (a
Corporate Event), the Company shall make appropriate provision to ensure that the Holder will thereafter have the right to receive upon a conversion of this Note, at the Holders option, (i) in addition to the shares of
Common Stock receivable upon such conversion, such securities or other assets to which the Holder would have been entitled with respect to such shares of Common Stock had such shares of Common Stock been held by the Holder upon the consummation of
such Corporate Event (without taking into account any limitations or restrictions on the convertibility of this Note) or (ii) in lieu of the shares of Common Stock otherwise receivable upon such conversion, such securities or other assets
received by the holders of shares of Common Stock in connection with the consummation of such Corporate Event in such amounts as the Holder would have been entitled to receive had this Note initially been issued with conversion rights for the form
of such consideration (as opposed to shares of Common Stock) at a conversion rate for such consideration commensurate with the Conversion Price. Provision made pursuant to the preceding sentence shall be in a form and substance satisfactory to the
Required Holders. The provisions of this Section shall apply similarly and equally to successive Corporate Events and shall be applied without regard to any limitations on the conversion or redemption of this Note. (g) Other Corporate Events. (h) Whenever the Conversion Price is adjusted pursuant to Section (3) hereof, the Company shall promptly provide the Holder with a
written notice setting forth the Conversion Price after such adjustment and setting forth a brief statement of the facts requiring such adjustment. (i) In case of any (1) merger or consolidation of the Company or any Subsidiary of the Company with or into another Person, or
(2) sale by the Company or any Subsidiary of the Company of more than one-half of the assets of the Company in one or a series of related transactions, a Holder shall have the right to (A) exercise
any rights under Section (2)(b), (B) convert the aggregate amount of this Note then outstanding into the shares of stock and other securities, cash and property receivable upon or deemed to be held by holders of Common Stock following such merger,
consolidation or sale, and such Holder shall be entitled upon such event or series of related events to receive such amount of securities, cash and property as the shares of Common Stock into which such aggregate Principal amount of this Note could
have been converted immediately prior to such merger, consolidation or sales would have been entitled, or (C) in the case of a merger or consolidation, require the surviving entity to issue to the Holder a convertible Note with a Principal
amount equal to the aggregate Principal amount of this Note then held by such Holder, plus all accrued and unpaid interest and other amounts owing thereon, which such newly issued convertible Note shall have terms identical (including with respect
to conversion) to the terms of this Note, and shall be entitled to all of the rights and privileges of the  9




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Holder of this Note set forth herein and the agreements pursuant to which this Note was issued. In the case of clause (C), the conversion price applicable for the newly issued shares of
convertible preferred stock or convertible debentures shall be based upon the amount of securities, cash and property that each share of Common Stock would receive in such transaction and the Conversion Price in effect immediately prior to the
effectiveness or closing date for such transaction. The terms of any such merger, sale or consolidation shall include such terms so as to continue to give the Holder the right to receive the securities, cash and property set forth in this Section
upon any conversion or redemption following such event. This provision shall similarly apply to successive such events. (4) REISSUANCE
OF THIS NOTE. (a) Transfer. If this Note is to be transferred, the Holder shall surrender this Note to the Company, whereupon
the Company will forthwith issue and deliver upon the order of the Holder a new Note (in accordance with Section (4)(d)), registered in the name of the registered transferee or assignee, representing the outstanding Principal being transferred by
the Holder (along with any accrued and unpaid interest thereof) and, if less then the entire outstanding Principal is being transferred, a new Note (in accordance with Section (4)(d)) to the Holder representing the outstanding Principal not being
transferred. The Holder and any assignee, by acceptance of this Note, acknowledge and agree that, by reason of the provisions of Section (3)(b)(iii) following conversion or redemption of any portion of this Note, the outstanding Principal
represented by this Note may be less than the Principal stated on the face of this Note. (b) Lost, Stolen or Mutilated Note. Upon
receipt by the Company of evidence reasonably satisfactory to the Company of the loss, theft, destruction or mutilation of this Note, and, in the case of loss, theft or destruction, of any indemnification undertaking by the Holder to the Company in
customary form and, in the case of mutilation, upon surrender and cancellation of this Note, the Company shall execute and deliver to the Holder a new Note (in accordance with Section (4)(d)) representing the outstanding Principal. (c) Note Exchangeable for Different Denominations. This Note is exchangeable, upon the surrender hereof by the Holder at the principal
office of the Company, for a new Note or Notes (in accordance with Section (4)(d)) representing in the aggregate the outstanding Principal of this Note, and each such new Note will represent such portion of such outstanding Principal as is
designated by the Holder at the time of such surrender. (d) Issuance of New Notes. Whenever the Company is required to issue a
new Note pursuant to the terms hereof, such new Note (i) shall be of like tenor with this Note, (ii) shall represent, as indicated on the face of such new Note, the Principal remaining outstanding (or in the case of a new Note being issued
pursuant to Section 5(4)(a) or Section 5(4)(c), the Principal designated by the Holder which, when added to the Principal represented by the other new Note issued in connection with such issuance, does not exceed the Principal remaining
outstanding under this Note immediately prior to such issuance of new Note), (iii) shall have an issuance date, as indicated on the face of such new Note, which is the same as the Issuance Date of this Note, (iv) shall have the same rights and
conditions as this Note, and (v) shall represent accrued and unpaid Interest from the Issuance Date.  10




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(5) NOTICES. Any notices, consents, waivers or other communications required or
permitted to be given under the terms hereof must be in writing by letter and email and will be deemed to have been delivered: upon the later of (A) either (i) receipt, when delivered personally or (ii) one (1) Business Day after deposit
with an overnight courier service with next day delivery specified, in each case, properly addressed to the party to receive the same and (B) receipt, when sent by electronic mail. The addresses and e -mail addresses for such
communications shall be:  If to the Company, to:

SMX (Security Matters) Public Limited CompanyMespil Business Centre Mespil House
Sussex Road Dublin 4
D04 T4A6 Attention: Haggai Alon Email:
haggai@securitymattersltd.comwith a copy (which shall not constitute notice) to:

Ruskin Moscou Faltischek, P.C. 1425 RXR
Plaza East Tower, 15th Floor Uniondale, NY 11556
Attention: Stephen E. Fox, Esq. Email:
SFox@rmfpc.comIf to the Holder:

YA II PN, Ltdc/o Yorkville Advisors Global, LLC 1012
Springfield AvenueMountainside, NJ 07092Attention: Mark AngeloTelephone: 201-985-8300Email: Legal@yorkvilleadvisors.com or at such other address and/or email and/or to the attention of such other person as the recipient party has specified by
written notice given to each other party three (3) Business Days prior to the effectiveness of such change. Written confirmation of receipt (i) given by the recipient of such notice, consent, waiver or other communication,
(ii) electronically generated by the senders email service provider containing the time, date, recipient email address or (iii) provided by a nationally recognized overnight delivery service, shall be rebuttable evidence of personal
service, receipt by facsimile or receipt from a nationally recognized overnight delivery service in accordance with clause (i), (ii) or (iii) above, respectively. (1) Except as expressly provided herein, no provision of this Note shall alter or impair the obligations of the Company, which are absolute
and unconditional, to pay the Principal of, interest and other charges (if any) on, this Note at the time, place, and rate, and in the currency, herein prescribed. This Note is a direct obligation of the Company. As long as this Note is outstanding,
the Company shall not and shall cause their subsidiaries not to, enter into any agreement to adversely affect any rights of the Holder.  11




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(2) This Note shall not entitle the Holder to any of the rights of a stockholder of the
Company, including without limitation, the right to vote, to receive dividends and other distributions, or to receive any notice of, or to attend, meetings of stockholders or any other proceedings of the Company, unless and to the extent converted
into shares of Common Stock in accordance with the terms hereof. (3) CHOICE OF LAW; VENUE; WAIVER OF JURY TRIAL (a) Governing Law. This Note and the rights and obligations of the Parties hereunder shall, in all respects, be governed by, and
construed in accordance with, the laws (excluding the principles of conflict of laws) of the State of New York (the Governing Jurisdiction) (including Section 5-1401 and Section 5-1402 of the General Obligations Law of the State of New York), including all matters of construction, validity and performance. (b) Jurisdiction; Venue; Service. (i) The Company hereby irrevocably consents to the non-exclusive personal jurisdiction of the state
courts of the Governing Jurisdiction and, if a basis for federal jurisdiction exists, the non-exclusive personal jurisdiction of any United States District Court for the Governing Jurisdiction. (ii) The Company agrees that venue shall be proper in any court of the Governing Jurisdiction selected by the Holder or, if a basis for
federal jurisdiction exists, in any United States District Court in the Governing Jurisdiction. The Company waives any right to object to the maintenance of any suit, claim, action, litigation or proceeding of any kind or description, whether in law
or equity, whether in contract or in tort or otherwise, in any of the state or federal courts of the Governing Jurisdiction on the basis of improper venue or inconvenience of forum. (iii) Any suit, claim, action, litigation or proceeding of any kind or description, whether in law or equity, whether in contract or tort or
otherwise, brought by the Company against the Holder arising out of or based upon this Note or any matter relating to this Note, or any other Transaction Document, or any contemplated transaction, shall be brought in a court only in the Governing
Jurisdiction. The Company shall not file any counterclaim against the Holder in any suit, claim, action, litigation or proceeding brought by the Holder against the Company in a jurisdiction outside of the Governing Jurisdiction unless under the
rules of the court in which the Holder brought such suit, claim, action, litigation or proceeding the counterclaim is mandatory, and not permissive, and would be considered waived unless filed as a counterclaim in the suit, claim, action, litigation
or proceeding instituted by the Holder against the Company. The Company agrees that any forum outside the Governing Jurisdiction is an inconvenient forum and that any suit, claim, action, litigation or proceeding brought by the Company against the
Holder in any court outside the Governing Jurisdiction should be dismissed or transferred to a court located in the Governing Jurisdiction. Furthermore, the Company irrevocably and unconditionally agrees that it will not bring or commence any suit,
claim, action, litigation or proceeding of any kind or  12




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description, whether in law or equity, whether in contract or in tort or otherwise, against the Holder arising out of or based upon this Note or any matter relating to this Note, or any other
Transaction Document, or any contemplated transaction, in any forum other than the courts of the State of New York sitting in New York County, and the United States District Court of the Southern District of New York, and any appellate court from
any thereof, and each of the parties hereto irrevocably and unconditionally submits to the jurisdiction of such courts and agrees that all claims in respect of any such suit, claim, action, litigation or proceeding may be heard and determined in
such New York State Court or, to the fullest extent permitted by applicable law, in such federal court. The Company and the Holder agree that a final judgment in any such suit, claim, action, litigation or proceeding shall be conclusive and may be
enforced in other jurisdictions by suit on the judgment or in any other manner provided by law. (iv) The Company and the Holder
irrevocably consent to the service of process out of any of the aforementioned courts in any such suit, claim, action, litigation or proceeding by the mailing of copies thereof by registered or certified mail postage prepaid, to it at the address
provided for notices in this Note, such service to become effective thirty (30) days after the date of mailing. (v) Nothing herein
shall affect the right of the Holder to serve process in any other manner permitted by law or to commence legal proceedings or to otherwise proceed against the Company or any other Person in the Governing Jurisdiction or in any other jurisdiction. (c) THE PARTIES MUTUALLY WAIVE ALL RIGHT TO TRIAL BY JURY OF ALL CLAIMS OF ANY KIND ARISING OUT OF OR BASED UPON THIS NOTE OR ANY MATTER
RELATING TO THIS NOTE, OR ANY OTHER TRANSACTION DOCUMENT, OR ANY CONTEMPLATED TRANSACTION. THE PARTIES ACKNOWLEDGE THAT THIS IS A WAIVER OF A LEGAL RIGHT AND THAT THE PARTIES EACH MAKE THIS WAIVER VOLUNTARILY AND KNOWINGLY AFTER CONSULTATION WITH
COUNSEL OF THEIR RESPECTIVE CHOICE. THE PARTIES AGREE THAT ALL SUCH CLAIMS SHALL BE TRIED BEFORE A JUDGE OF A COURT HAVING JURISDICTION, WITHOUT A JURY. (4) If the Company fails to strictly comply with the terms of this Note, then the Company shall reimburse the Holder promptly for all fees,
costs and expenses, including, without limitation, attorneys fees and expenses incurred by the Holder in any action in connection with this Note, including, without limitation, those incurred: (i) during any workout, attempted workout,
and/or in connection with the rendering of legal advice as to the Holders rights, remedies and obligations, (ii) collecting any sums which become due to the Holder, (iii) defending or prosecuting any proceeding or any counterclaim to
any proceeding or appeal; or (iv) the protection, preservation or enforcement of any rights or remedies of the Holder. (5) Any
waiver by the Holder of a breach of any provision of this Note shall not operate as or be construed to be a waiver of any other breach of such provision or of any breach of any other provision of this Note. The failure of the Holder to insist upon
strict adherence to any term of this Note on one or more occasions shall not be considered a waiver or deprive that party of the right thereafter to insist upon strict adherence to that term or any other term of this Note. Any waiver must be in
writing.  13




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(6) If any provision of this Note is invalid, illegal or unenforceable, the balance of this
Note shall remain in effect, and if any provision is inapplicable to any person or circumstance, it shall nevertheless remain applicable to all other persons and circumstances. If it shall be found that any interest or other amount deemed interest
due hereunder shall violate applicable laws governing usury, the applicable rate of interest due hereunder shall automatically be lowered to equal the maximum permitted rate of interest. The Company covenants (to the extent that it may lawfully do
so) that it shall not at any time insist upon, plead, or in any manner whatsoever claim or take the benefit or advantage of, any stay, extension or usury law or other law which would prohibit or forgive the Company from paying all or any portion of
the Principal of or interest on this Note as contemplated herein, wherever enacted, now or at any time hereafter in force, or which may affect the covenants or the performance of this indenture, and the Company (to the extent it may lawfully do so)
hereby expressly waives all benefits or advantage of any such law, and covenants that it will not, by resort to any such law, hinder, delay or impeded the execution of any power herein granted to the Holder, but will suffer and permit the execution
of every such as though no such law has been enacted. (7) CERTAIN DEFINITIONS. For purposes of this Note, the following terms
shall have the following meanings: (a) Bloomberg means Bloomberg Financial Markets. (b) Business Day means any day except Saturday, Sunday and any day which shall be a federal legal holiday in the United
States or a day on which banking institutions are authorized or required by law or other government action to close. (c) Buy-In shall have the meaning set forth in Section (3)(b)(ii). (d) Buy-In Price shall have the meaning set forth in Section (3)(b)(ii). (e) Change of
Control Transaction means the occurrence of (a) an acquisition after the date hereof by an individual or legal entity or group (as described in Rule 13d-5(b)(1) promulgated under the
Exchange Act) of effective control (whether through legal or beneficial ownership of capital stock of the Company, by contract or otherwise) of in excess of fifty percent (50%) of the voting power of the Company (except that the acquisition of
voting securities by the Holder or any other current holder of convertible securities of the Company shall not constitute a Change of Control Transaction for purposes hereof), (b) a replacement at one time or over time of more than one-half of the members of the board of directors of the Company (other than as due to the death or disability of a member of the board of directors) which is not approved by a majority of those individuals who are
members of the board of directors on the date hereof (or by those individuals who are serving as members of the board of directors on any date whose nomination to the board of directors was approved by a majority of the members of the board of
directors who are members on the date hereof), (c) the merger, consolidation or sale of fifty percent (50%) or more of the assets of the Company or any Subsidiary of the Company in one or a series of related transactions with or into another entity,
or (d) the execution by the Company of an agreement to which the Company is a party or by which it is bound, providing for any of the events set forth above in (a), (b) or (c). No transfer to a wholly-owned Subsidiary shall be deemed a Change
of Control Transaction under this provision.  14




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(f) Closing Price means the price per share in the last reported trade
of the Common Stock on a Primary Market or on the exchange which the Common Stock is then listed as quoted by Bloomberg. (g)
Commission means the U.S. Securities and Exchange Commission. (h) Conversion Amount means the
portion of the Principal, Interest, or other amounts outstanding under this Note to be converted, redeemed or otherwise with respect to which this determination is being made. (i) Conversion Date shall have the meaning set forth in Section (3)(b)(i). (j) Conversion Failure shall have the meaning set forth in Section (3)(b)(ii). (k) Conversion Notice shall have the meaning set forth in Section (3)(b)(i). (l) Conversion Price means, as of any Conversion Date or other date of determination the lower of (i) $3.65 per share of
Common Stock (the Fixed Price), or (ii) 93% of the lowest daily VWAP during the 7 consecutive Trading Days immediately preceding the Conversion Date or other date of determination (the Variable Price), but not
lower than the Floor Price. The Conversion Price shall be adjusted from time to time pursuant to the other terms and conditions of this Note. (m) Calendar Month means one of the months as named in the calendar. (n) Common Stock means the ordinary shares, par value $0.0001, of the Company and stock of any other class into which such
shares may hereafter be changed or reclassified. (o) Exchange Act means the Securities Exchange Act of 1934, as
amended. (p) Floor Price means the lower of (i) $0.50 per share, or 20% of the VWAP on the Trading Day immediately
prior to the effectiveness of the initial Underlying Shares Registration Statement.  15




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(q) Fundamental Transactionmeans any of the following:
(1) the Company effects any merger or consolidation of the Company with or into another Person and the Company is the non-surviving company (other than a merger or consolidation with a wholly owned
Subsidiary of the Company for the purpose of redomiciling the Company), (2) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (3) any tender offer or exchange offer (whether by
the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property, or (4) the Company effects any reclassification of the Common Stock
or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property. (r) Other Notes means any other notes issued pursuant to the SEPA and any other debentures, notes, or other instruments
issued in exchange, replacement, or modification of the foregoing. (s) Payment Premium means 7% of the Principal
amount being paid. (t) Periodic Reports shall mean the Companys (i) Annual Report on Form 20-F for the fiscal year ending December 31, 2022, and (ii) all other reports required to be filed by the Company with the Commission under applicable laws and regulations (including, without limitation,
Regulation S-K) for so long as any amounts are outstanding under this Note or any Other Note; provided that all such Periodic Reports shall include, when filed, all information, financial statements,
audit reports (when applicable) and other information required to be included in such Periodic Reports in compliance with all applicable laws and regulations. (u) Person means a corporation, an association, a partnership, organization, a business, an individual, a government or
political subdivision thereof or a governmental agency. (v) Primary Market shall mean the Nasdaq Stock Market;
provided however, that in the event the share of Common Stock are ever listed or traded on the New York Stock Exchange, or the NYSE American, then the Principal Market shall mean such other market or exchange on which the shares of
Common Stock are then listed or traded to the extent such other market or exchange is the principal trading market or exchange for the Common Stock. (w) Securities Act means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder. (x) Share Delivery Date shall have the meaning set forth in Section (3)(b)(i). (y) Subsidiary means, with respect to any Person, any corporation, association, partnership or other business entity of
which more than 50% of the total voting power of shares of capital stock or other interests (including partnership interests) entitled (without regard to the occurrence of any contingency) to vote in the election of directors, managers, general
partners or trustees thereof is at the time owned or controlled, directly or indirectly, by (i) such Person; (ii) such Person and one or more Subsidiaries of such Person; or (iii) one or more Subsidiaries of such Person. (z) Trading Day means a day on which the shares of Common Stock are quoted or traded on a Primary Market on which the
shares of Common Stock are then quoted or listed; provided, that in the event that the shares of Common Stock are not listed or quoted, then Trading Day shall mean a Business Day.  16




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(aa) Transaction Document means, each of, the Other Notes, the SEPA, the
Registration Rights Agreement and any and all documents, agreements, instruments or other items executed or delivered in connection with any of the foregoing. (bb) Trigger Event shall mean (i) the daily VWAP is less than the Floor Price for five Trading Days during a period
of seven consecutive Trading Days (a Floor Price Trigger), or (ii) the Company has issued in excess of 95% of the Common Stock available under the Exchange Cap (an Exchange Cap Trigger) (the last such day
of each such occurrence, a Trigger Date). (cc) Triggered Principal Amount shall have the meaning
set forth in Section (1)(c). (dd) Underlying Shares means the shares of Common Stock issuable upon conversion of this
Note or as payment of interest in accordance with the terms hereof. (ee) Underlying Shares Registration Statement
means a registration statement meeting the requirements set forth in the Registration Rights Agreement, covering among other things the resale of the Underlying Shares and naming the Holder as a selling stockholder thereunder. (ff) VWAP means, for any security as of any date, the daily dollar volume-weighted average price for such security on the
Primary Market during regular trading hours as reported by Bloomberg through its Historical Prices  Px Table with Average Daily Volume functions. [Signature Page Follows]  17




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IN WITNESS WHEREOF, the Company has caused this Convertible Promissory Note to be
duly executed by a duly authorized officer as of the date set forth above.  COMPANY:SMX (SECURITY MATTERS) PUBLICLIMITED COMPANYBy:

/s/ Haggai AlonName:

Haggai AlonTitle:

CFO




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EXHIBIT I CONVERSION NOTICE (To be executed by the Holder in order to Convert the Note) TO: SMX (SECURITY MATTERS) PUBLIC LIMITED COMPANY Via Email: The undersigned hereby
irrevocably elects to convert a portion of the outstanding and unpaid Conversion Amount of the Convertible Promissory Note issued on March 8, 2023 (No. SMX-1) into Shares of Common Stock of SMX
(SECURITY MATTERS) PUBLIC LIMITED COMPANY, according to the conditions stated therein, as of the Conversion Date written below.  Conversion Date:Principal Amount to be Converted:Accrued Interest to be Converted:Total Conversion Amount to be converted:Fixed Price:Variable Price:Applicable Conversion Price:Number of shares of Common Stock to be issued:Please issue the shares of Common Stock in the following name and deliver them to the following account:Issue to:Broker DTC Participant Code:Account Number:  Authorized Signature:Name:Title: