Method and system of payment by electronic cheque

• US 20060287955A1
• Filed: 12/30/2004
• Published: 12/21/2006
• Est. Priority Date: 07/25/1997
• Status: Active Grant

• Current Assignee: Joan Daemen, Michel Dawirs, Yves Moulart
• Original Assignee: Joan Daemen, Michel Dawirs, Yves Moulart
• Inventors: Daemen, Joan, Moulart, Yves, Dawirs, Michel
• Granted Patent: US 7,505,944 B2
• Time in Patent Office: Days
• US Class Current: 705/44
• CPC Class Codes: G06Q 20/04 Payment circuits
• CPC Class Codes: G06Q 20/0425 the cheque being electronic only
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/3674 involving authentication
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: G06Q 20/3821 Electronic credentials
• CPC Class Codes: G06Q 20/40 Authorisation, e.g. identification of payer or payee, verification of customer or shop credentials; Review and approval of payers, e.g. check credit lines or negative lists
• CPC Class Codes: G06Q 20/401 Transaction verification
• CPC Class Codes: G06Q 20/4093 Monitoring of device authentication
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system

Abstract

An offline payment method includes communicating a commitment value calculated by an electronic check medium to a terminal configured to receive a payment from the electronic check medium. The commitment value is calculated based on a first authentication code and a secret key, wherein the first authentication code is calculated based on a payment amount and a secret verification key. The terminal determines and communicates a random/pseudo-random guesstimation to the electronic check medium in response to receiving the verification code, the random/pseudo-random guesstimation being configured to verify that the electronic check medium is authentic. The electronic check medium determines and communicates a second authentication code to the terminal, the second authentication based upon the random/pseudo-random guesstimation. The terminal compares the second authentication with the random/pseudo-random guesstimation to verify the second authentication and accepts payment from the electronic check medium when the second authentication is verified.

Claims

1. A method of payment by electronic cheque between a payment issuer furnished with a medium that includes a blank electronic cheque certified by a financial institution (BA) and an overall amount useable at least partially in respect of the electronic cheque, and a recipient of the payment furnished with a device adapted to receive said electronic cheque of the above mentioned medium, said method comprising the steps of:

calculating by the medium of a table, possibly partial, based on at least one set of k base values (S[1], . . . S[k]), by applying successively to each of the base values n times an irreversible function (OWF) with parameter(s) differing preferably with each application and giving k intermediate values n times, wherein said irreversible function is a function from which it is easy to compute the output for a given input, but it is computationally infeasible to compute for a given output an input which maps to the given output;

calculating by the medium of a secret key (SK) based on the last k intermediate values of order n and, on the basis of this key (SK), calculating a distinctive sign (IM_CF) of the cheque;

transmitting by the medium to the device the distinctive sign (IM_CF) calculated for the electronic cheque;

generating a financial commitment by the medium in relation to the device, as regards the cheque by supplying to the device;

a first result (O_AC_I) of the irreversible function (OWF), obtained by processing a value (AC_I), according to a formula O_AC_I=OWF (AC_I), the value AC_I being a product of a first algorithm (MAC) combining a secret verification key (SVK), originating from the financial institution (BA) issuing the electronic cheque, and dynamic parameter (CDP) of this cheque, according to a formula AC_I=MAC (SVK, CDP), and

a second result (AC_C) of a second algorithm (MAC) combining the secret key (SK) calculated for the medium, the dynamic parameters (CDP) of this cheque and the first result (O_AC_I), according to a formula AC_C=MAC (SK, CDP ♦

O_AC_I), wherein ♦

signifies a chaining of data,

generating by the device, at least one random/pseudorandom guesstimation of k numbers m of successive applications of the irreversible function (OWF) to the k base values (S[1], . . . S[k]), the k numbers m lying between zero, the sum of the k numbers m having to be a determined constant;

transmitting by said device the result of the guesstimation to the medium;

responding by the medium to said guesstimation by the device with a response that includes the result (AC_I) of the first algorithm combining the secret verification key (SVK) and the dynamic parameters (CDP) of the cheque and, a set of the k intermediate values obtained during the successive applications of the irreversible function (OWF) to each of the k base values (S[1], . . . S[k]), the number or numbers of times m lying between zero and n;

successively applying, by said device, the irreversible function (OWF) to each of the k intermediate values of order(s) m until the last k intermediate values of order n are obtained;

calculating said secret key (SK), by said device, based on these last k intermediate values of order n and, based on said secret key (SK), a calculation of the distinctive sign (IM_CF) of the cheque;

comparing, by said device, the distinctive sign (IM_CF) thus calculated by the device and the distinctive sign (IM_CF) calculated by the medium and received from the latter; and

verifying by calculation and comparison in the device of said second result (AC_C) of the second algorithm (MAC) calculated by the device and said second result received from the medium;

verifying by calculation and comparison in the device of said first result (O_AC_I) of an irreversible function (OWF) calculated by the device and said first result received from the medium, wherein, if said comparisons and verifications each give equality, an acceptance and a storage by the device (3) of the electronic cheque issued by the medium, thereby allowing the device to recognize the authenticity of the medium and of the cheque being received.

2. Method according to claim 1, wherein the sum of the k numbers m is a constant equal to n*k/2 if the product n*k is even or, if this product is odd, to (n*k−

1)/2.

3. Method according to claim 1, comprising:

a storage of the medium (1) of at least one electronic cheque template (CF) useable to make at least one aforesaid cheque,

a transmission by the medium (1) to the device (3) of;

a series of h distinctive sign (IM_CF[1 . . . h]) of a cheque, each associated with a distinct set of k base values (S [1], . . . S [k]), contained in the medium (1),

an index (i), lying between 1 and h, for designating a particular distinctive sign (IM_CF[i]) from among the h aforementioned distinctive signs,

a digital signature (SIGN_CF) produced by the issuing financial institution (BA) so as to guarantee the said distinctive signs (IM_CF[1 . . . h]), and

a use by the device (3), for the said comparison, of the particular distinctive sign (IM_CF[i]) determined by the index (i) in the guise of distinctive sign (IM_CF) received from the medium (1), and

a verification by the device (3) for the said digital signature (SIGN_CF) by means of a public key (PK_B) known to the device (3).

4. Method according to claim 1, which

comprises, in respect of the transaction, a transmission by the medium (1) to the device (3) of non-secret data which may be the identification (ID_B) of the financial institution (BA) which certifies the electronic cheque and, as appropriate, the public key (PK_B) of the issuing financial institution (BA) and a certificate (CERT_B) of this public key (PK_B) issued by a certificate authority (CA), and wherein

the device (3) verifies in this case the authenticity of the said certificate (CERT_B) by means of another public key (PK_CA), known to the device (3), of the certificate authority (CA).

5. Method according to claim 1, wherein the medium (1) can be reloaded as regards its overall amount and/or its number (i) of electronic cheques in the course of a link with the abovementioned financial institution (BA) or one of its delegates.

6. Method according to claim 1, comprising, for the calculation of the table (5) by the medium (1), a mother base value (SDCF) common to each column (1 . . . k) of the table (5), and an application to this mother base value of at least one irreversible function (SOWF) preferably with different parameter(s) for each column (1 . . . k).

7. Method according to claim 5, wherein in the course of reloading of the medium (1), the medium is furthermore supplied with an identification (ID_CF) of cheque templates, updated abovementioned static parameters (SP_CF), a series of h distinctive signs (IM_CF[1 . . . h]), an abovementioned digital signature (SIGN_CF) and a determined number of base values ((S[1], . . . S[k]), or, as appropriate, of at least one aforesaid common base value (SD_CF).

8. Method according to claim 1, wherein the device (3) records, during a transaction, the result (AC_I) of the first algorithm and/or, as appropriate, an identification (ID_B) of the aforesaid financial institution (BA) and/or an identification (ID_CF) of the template of the electronic cheque received and/or the identification (ID_C) of the medium (1).

9. Method according to claim 1, wherein

in respect of incremental payments of the kind by telephone card, the dynamic parameters (CDP) of the cheques moreover comprise

the amount or the sequence of amounts corresponding to the authorized incremental payments,

a base chaining value (Z_O),

a chaining of successive values (Z_j) which each stem successively from the application of an irreversible function to the immediately following value (Z_j+1,), and wherein

after having performed with the hereinabove device (3) a protocol for payment by electronic cheque, the medium (1) can perform an incremental payment by supplying the receiving device (3) with successive chaining values (Z₁, Z₂, Z₃, . . . ), the device (3) preserving a record of the last value (Z_j) received and of the corresponding index (j).

10. Method according to claim 1, which comprises a cancellation of a transaction of payment by cheque from the medium (1) to the device (3).

11. method according to claim 10, which comprises in respect of the aforementioned cancellation,

a storage, in the device (3), of at least one electronic cheque template, issued by the financial institution (BB) of the device (3), and of secret data relating to this template,

a programming of the medium (1) in such a way that the latter cannot receive a payment by cheque other than from the device (3) to which a transaction was previously paid by means of the said medium (1) the latter storing the cancellation payment cheque until the medium (1) is presented to its corresponding financial institution (BA), in particular for a reloading of the medium (1).

12. Method according to claim 1, which furthermore comprises steps of inverse authentication via which the medium (1) can for its part recognize the authenticity of the device (3).

13. Method according to claim 12, wherein the steps of inverse authentication are of the same kind as those for the authentication of the medium (1), whilst requiring, as appropriate, only a single distinctive sign (IM_CF) of electronic cheque template.

14. Method according to claim 12, which comprises, for at least some of the inverse authentication steps, the use of an element (7) for communication between the medium (1) and the device (3), this communication element (7) preferably being held by the payment issuer which holds the said medium (1).

15. Method according to claim 1, which comprises, in the medium (1), a combination of each of the various distinctive signs (IM_CF[i]), at a first level, by means of irreversible functions (OWHF) each time with another value or another distinctive sign ((IM_CF[i′

]), whereas the results (V₁, V₂, V₃, V₄) of each pair of application of the irreversible function (OWHF) are combined at a second level via another application of the irreversible function (OWHF) so as to give new results (V₅, V₆) to be combined at a third level via one or another applications of the irreversible function (OWHF) and so on and so forth until a single result (O_IM_CF) is obtained, and which is signed as deduced distinctive sign, by the digital signature (SIGN_CF) so as to sign the cheque issued.

16. Method according to claim 15, which comprises, for a verification by the device (3) of the deduced distinctive sign (O_IM_CF), a transmission from the medium (1) each time of the second distinctive sign (IM_CF[i]) used in a first combination (OWHF) at the first level and, at each succeeding level, of the intermediate result (V₂, V₆) of the irreversible functions (OWHF), which is used so as to be combined successively with the corresponding intermediate result (V₁, V₅) obtained on the basis of the second distinctive sign (IM_CF[i]), until the deduce distinctive sign (O_IM_CF) is obtained.

17. Payment system for implementing the method according to claim 1, comprising

at least one medium (1) furnished

with means for storing at least

a blank electronic cheque certified by a financial institution (BA),

an overall amount useable at least partially in respect of the electronic cheque,

at least one distinctive sign (IM_CF) for this cheque, which may be included in the latter,

at least one set of k base value (S[11, . . . S[k]) which may be derived from a single mother value (SD_CF),

a secret verification key (SVK) originating from the financial institution (BA) issuing the electronic cheque, and

dynamic parameters (CDP) of the said cheque,

with means of calculation

of a table (5) on the basis of the k base values (S[1], . . . S[k]), by applying successively to each of them n times an irreversible function (OWF) with parameter(s) differing preferably with each application and giving k intermediate values n times, wherein said irreversible function is a function from which it is easy to compute the output for a give input, but it is computationally infeasible to compute for a given output an input which maps to the given output,

of a secret key (SK) on the basis of the last k intermediate values of order n and, on the basis of this key (SK), of a distinctive sign (IM_CF) of the cheque,

of a first result (O_AC_I) of an irreversible function (OWF), obtained by processing a value (AC_I), according to a formula O_AC_I=OWF (AC_I), said value (AC_I) being itself the result of a first algorithm (MAC) combining the secret verification key (SVK) and dynamic parameters (CDP) of the cheque, according to a formula AC_I=MAC (SVK, CDP), and

of a second result (ACC) of a second algorithm (MAC) combining the secret key (SK) calculated for the medium (1), the dynamic parameters (CDP) of this cheque and the first result (O_AC_I) hereinabove, according to a formula AC_C=MAC (SK, CDP ♦

O AC I) wherein ♦

signifies a chaining of data, and

with means of direct dialogue with at least one device (3) adapted to receive at least one aforesaid electronic cheque from the abovementioned medium (1) and among other things the distinctive sign (IM_CF) of the said cheque,

the device (3) being equipped

with means of random/pseudo-random guesstimation of k number m of successive applications of the irreversible function (OWF) to the k base values (S[1], . . . S[k]), the k number m lying between zero and n and possibly being different from one another, the sum of the k numbers m having to be a determined constant,

with means of direct dialogue corresponding to those of the medium (1), so as among other things to carry out a transmission of the result of the guesstimation to the medium (1),

with means of calculation

successively applying the irreversible function (OWF) to each of the k intermediate values of order m until the last k intermediate values of order n are obtained,

of the said secret key (SK) on the basis of these last k intermediate values of order n and, on the basis of this secret key (SK), a calculation of the distinctive sign (IM_CF) of the cheque,

means of comparison of the distinctive sign (IM_CF) thus calculated and of the distinctive sign (IM_CF) calculated by the medium (1) and received from the latter,

means of verification by calculation and comparison of the said second result (AC_C) of the second algorithm (MAC) and of that received from the medium (1),

means of verification by calculation and comparison of the said result (O_AC_I) of an irreversible function (OWF) and of that received from the medium (1) and,

means of storage of at least the electronic cheque issued by the medium (1), if the said comparison and verifications each give equality.

18. System according to claim 17, wherein

the means of storage of the medium (1) are devised so as to store at least one electronic cheque template (CF) useable to make at least one aforesaid cheque,

the means of dialogue of the medium (1) are devised so as to transmit to the device (3)

a series of h distinctive sign (IM_CF[1 . . . h]) of a cheque, each associated with a distinct set of k base values (S[1], . . . S[k]), contained in the medium (1),

an index (i), lying between 1 and h, for designating a particular distinctive sign (IM_CF[i]) from among the h aforementioned distinctive signs,

a digital signature (SIGN_CF) produced by the issuing financial institution (BA) so as to guarantee the said distinctive signs (IM_CF[1 . . . h]), and

the device (3) is devised so as to use, for the said comparison, the particular distinctive sign (IM_CF[i]) determined by the index, (i) in the guise of distinctive sign (IM_CF) received from the medium (1), and

the device (3) comprises means of calculation devised so as to verify the said digital signature (SIGN_CF) by means of a public key (PK_B) known to the device (3).

19. System according to claim 18, wherein

the means of dialogue of the medium (1) are devised, so as to transmit to the device (3) non-secret data which may be the identification (ID_B) of the financial institution (BA) which certifies the electronic cheque and, as appropriate, the public key (PK_B) of the issuing financial institution (BA) and a certificate (CERT_B) of this public key (PK_B) issued by a certificate authority (CA), and

the device is devised so as to verify the authenticity of the said certificate (CERT_B) by means of another public key (PK_CA), known to the device (3), of the certificate authority (CA).

20. System according to claim 17, comprising as medium (1) a payment card (2) of the integrated circuit type and as device (3) a payment terminal (4) with reading and writing for a cart (2) of this type.

21. System according to claim 20, comprising as medium (1) a payment card (2) of the integrated circuit type and as device (3) a payment terminal (4) with reading and writing for a card (2) of this type and furnished with means of transferring data received from the said card (2), and/or processed by the terminal (4), into storage means (6) detachable from the terminal (4) proper and in particular transportable to a financial institution (BB) so as to perform therein a transfer of the said data.

22. System according to claim 20, wherein, in particular in the case where the device (3) is remote from the issuer of the payment and/or in the case of steps of inverse authentication of the device (3) by the medium (1), the abovementioned medium (1) is composed among other things, on the one hand, of the aforesaid integrated circuit card (2) and, on the other hand, of a communication element (7), for dialogue between the card and the said device (3).

23. A method of offline payment by electronic check between a payment issuer furnished with a medium comprising at least one blank electronic check comprising a message authentication code algorithm and a set of irreversible functions, wherein an irreversible function is a function from which it is easy to compute the output for a given input, but it is computationally infeasible to compute for a given output an input which maps to the given output;

and a recipient of the payment furnished with an electronic check receiving device adapted to receive said electronic check of said medium, said electronic check receiving device comprising said message authentication code algorithm and said set of irreversible functions, said method comprising the steps of

calculating by said medium a secret key and a distinctive sign of said electronic check, said calculation based on the use of said message authentication code algorithm and application of said set of irreversible functions;

transmitting by said medium to the electronic check receiving device said distinctive sign;

generating by said medium;

a first authentication code, a financial commitment value, and a second authentication code;

said second authentication code obtained by applying said message authentication code algorithm to said financial commitment value with said secret key;

transmitting by said medium said financial commitment value and said second authentication code to said electronic check receiving device;

generating by said electronic check receiving device, in response to said financial commitment value, a challenge, said challenge based on the application of said set of irreversible functions;

transmitting by said electronic check receiving device said challenge to said medium;

generating by said medium, in response to said challenge, a response based on the application of said set of irreversible functions;

transmitting by said medium said first authentication code and said response to said electronic check receiving device, in response to said challenge received from said electronic check receiving device;

calculating, by said electronic check receiving device, said secret key of said electronic check and the distinctive sign of said electronic check by applying said set of irreversible functions to said response;

comparing, by said electronic check receiving device, the distinctive sign calculated by said electronic check receiving device and the distinctive sign received from said medium;

verifying by calculation and comparison by said electronic check receiving device, said financial commitment value and said second authentication code, said verifying based on use of said secret key, wherein, if said comparison and verification each give equality, said electronic check issued by said medium is accepted and stored by said electronic check receiving device, thereby, allowing said electronic check receiving device to recognize the authenticity of the medium and of the electronic check being received.

24. The method according to claim 23, wherein said first authentication code is generated via said message authentication code algorithm and based upon said secret key and dynamic parameters of said electronic check.

25. The method according to claim 23, wherein said financial commitment value is generated via application of said set of irreversible functions and based upon said first authentication code.

26. The method according to claim 23, wherein said second authentication code is generated via said message authentication code algorithm and based upon said secret key, dynamic parameters of said electronic check, and said financial commitment value.

27. The method according to 23, wherein said set of irreversible functions are chosen from the group consisting of:

a first parametrized irreversible function;

a second parametrized irreversible function; and

, an irreversible compression function.

28. A system for offline payment by electronic check, said system comprising

an electronic check medium, said electronic check medium comprising

an electronic check template;

a message authentication code algorithm;

a set of irreversible functions, wherein an irreversible function is a function from which it is easy to compute the output for a given input, but it is computationally infeasible to compute for a given output an input which maps to be given output;

a set of base values associated with distinctive signs;

a secret key;

an identifier of said electronic check medium'"'"'s bank;

a first public key of said electronic check medium'"'"'s bank; and

a first public key certificate;

an electronic check receiving device, said electronic check receiving device comprising

said message authentication code algorithm;

—

said set of irreversible functions;

a second public key of said electronic check receiving device'"'"'s bank; and

a second public key certificate.

29. The system according to claim 28 wherein said set of irreversible functions is chosen from the group consisting of:

a first parametrized irreversible function;

a second parametrized irreversible function; and

, an irreversible compression function.

30. The system according to claim 29 wherein said electronic check template comprises:

(1) an identifier of said electronic check template, (2) an identifier of said electronic check medium, (3) static parameters, (4) a series of distinctive signs, and (5) a digital signature from said electronic check medium'"'"'s bank.

31. The system according to claim 30, wherein said electronic check medium transmits to electronic check receiving device (1) said electronic check template;

(2) said identifier of said electronic check medium'"'"'s bank;

(3) said first public key of said electronic check medium'"'"'s bank;

(4) said first public key certificate; and

(5) an index associated with said series of distinctive signs to indicate which distinctive sign to use.

32. The system according to claim 31, wherein said electronic check receiving device verifies (1) said first public key certificate, and (2) said digital signature from said electronic check medium'"'"'s bank.

33. The system according to claim 32, wherein said electronic check medium calculates

a first authentication code via said message authentication code algorithm, based upon a secret verification key and dynamic parameters of said electronic check;

a financial commitment value via application of said set of irreversible functions, based upon said first authentication code; and

a second authentication code via said message authentication code algorithm, based upon said secret key, said dynamic parameters of said electronic check, and said financial commitment value, wherein said electronic check medium transmits said second authentication code and said financial commitment value to said electronic check receiving device.

34. The system according to claim 33, wherein said electronic check receiving device calculates at least one challenge via application of said second set of irreversible functions for the purpose of verifying said electronic check medium and transmits said challenge to said electronic check medium.

35. The system according to claim 34, wherein said electronic check medium transmits a response and said first authentication code to said electronic check receiving device in response to said challenge received from said electronic check receiving device.

36. The system according to claim 35, wherein said electronic check receiving device

calculates a second distinctive sign via application of said set of irreversible functions;

verifies whether said second distinctive sign corresponds with said distinctive sign based on said index received from said electronic check medium; and

verifies said first authentication code and said financial commitment value received from said electronic check medium, wherein, if the said verifications each give equality, said electronic check issued by said electronic check medium is accepted and stored by said electronic check receiving device, thereby, allowing said electronic check receiving device to recognize the authenticity of said electronic check medium and of said electronic check being received.

37. A system for offline payment by electronic check, said system comprising

an electronic check medium, said electronic check medium comprising

an electronic check template;

a message authentication code algorithm;

a set of irreversible functions, wherein an irreversible function is a function from which it easy to compute the output for a given input, but it is computationally infeasible to compute for a given output an input which maps to the given output;

a set of base values associated with distinctive signs;

a secret key;

an identifier of said electronic check medium'"'"'s bank;

a first public key of said electronic check medium'"'"'s bank; and

a first public key certificate.

38. The system according to claim 37 wherein said set of irreversible functions is chosen from the group consisting of:

a first parametrized irreversible function;

a second parametrized irreversible function; and

, an irreversible compression function.

39. A method of offline payment using an electronic check medium with a memory and an integrated circuit residing thereon, comprising:

communicating a commitment value calculated by the electronic check medium to a terminal configured to receive a payment from the electronic check medium, the commitment value being calculated based on a first authentication code and a secret key, wherein the first authentication code is calculated based on a payment amount and a secret verification key;

communicating to the electronic check medium a random/pseudo-random guesstimation determined by the terminal in response to receiving at least the verification code, the random/pseudo-random guesstimation being configured to verify that the electronic check medium is authentic;

communicating to the terminal a second authentication code determined by the electronic check medium, the second authentication code being based on the random/pseudo-random guesstimation;

verifying the received second authentication by comparing the second authentication code with the random/pseudo-random guesstimation; and

accepting payment from the electronic check medium in response to verifying the second authentication.

40. The method of claim 39, further comprising calculating the first authentication code, wherein the secret verification key verifies the issuing bank.

41. The method of claim 39, further comprising calculating the first authentication code, wherein the first authentication code contains information specifying a maximum number of times that the electronic check medium may be used to make payments therefrom.

42. The method of claim 41 further comprising:

calculating a number of times that payment has been made from the electronic check medium; and

permitting payment only when the electronic check medium has not been used for payment more times than the maximum number of times.

43. The method according to claim 39 wherein receiving the specification further comprises receiving an identification of a party that is to receive payment.

44. The method of claim 39, wherein the payment amount corresponds to an amount to be received by the electronic check medium from the terminal.

45. The method of claim 39, further comprising generating an audit trail by the electronic check medium, the audit trail corresponding to the sum of previous payment amounts plus the payment amount made to the terminal, such that a predefined maximum transaction amount associated with the electronic check medium is not exceeded.