Apparatus and system having multi-party cryptographic authentication

1. An electronic device comprising:

one or more processors that:

perform at least one secure multiparty cryptographic computation using a plurality of modules that jointly generate authentication data based on input data, wherein each of the modules performs that module's part of the secure multiparty cryptographic process using secure data unique to each module that is not shared outside that module; and

update the respective secure data of at least two of the modules,

wherein the respective secure data of a first module of the at least two of the modules is updated using a modification value, each of the at least two of the modules determine the modification value, wherein the modification value is determined using at least a public key associated with the first module of the at least two of the modules and at least a public key associated with the second module of the at least two of the modules, and

wherein the respective secure data of a second module of the at least two of the module is updated using the modification value, and

wherein the updated secure data is arranged so that, for each possible value of the operation data, performance of the secure multiparty computation using the updated secure data generates the same authentication data as performance of the secure multiparty computation using the secure data prior to the step of updating; and

an output interface that transmits to a terminal the generated authentication data,

wherein the electronic device is authorized using the authentication data to provide improved security.

2. The electronic device of claim 1 , wherein the cryptographic computation is based, at least in part, on a key, wherein said updating does not change said key.

3. The electronic device of claim 1 , wherein updating the respective secure data of the at least two of the modules comprises:

the first module of the at least two of the modules adding the modification value to the respective secure data of the first module; and

the second module of the at least two of the modules subtracting the modification value from the respective secure data of the second module.

4. The electronic device of claim 1 , wherein determining the modification value further comprises a public-private key exchange between the at least two modules.

5. The electronic device of claim 4 , wherein the public-private key exchange is based, at least in part, on elliptic curve cryptography.

6. The electronic device of claim 1 , wherein the modification value is determined using at least a public key associated with the first module of the at least two of the modules and a public key associated with the second module of the at least two of the modules, and wherein the one or more processors further:

update the respective public keys using at least the modification value such that a new modification value is determinable using at least the updated respective public keys.

7. The electronic device of claim 1 , wherein, prior to updating the respective secure data of the at least two modules, the one or more processors:

check that the updated respective secure data will have positive values; and then

update the respective secure data of the at least two modules only if the updated respective secure data will have positive values.

8. The electronic device of claim 7 , wherein:

if either the updated respective secure data of the first module or the updated respective secure data of the second module will have a negative value, the one or more processors perform a corresponding predetermined action indicative of a negative value.

9. The electronic device of claim 1 , wherein the one or more processors further:

count the number of times the respective secure data of at least two of the modules has been updated; and

update the respective secure data of at least two of the modules only if the counted number of times the respective secure data of at least two of the modules has been updated is less than a threshold value.

10. The electronic device of claim 9 , wherein

if the counted number of times the respective secure data of at least two of the modules has been updated is greater than or equal to a threshold value, the one or more processors perform a corresponding predetermined action indicative of the threshold value having been reached.

11. The electronic device of claim 1 , wherein the cryptographic computation comprises a data encryption process and the authentication data comprises an encryption cryptogram.

12. The electronic device of claim 1 , wherein the cryptographic computation comprises a keyed hash function and the authentication data comprises a message authentication code.

13. The electronic device of claim 1 , wherein the cryptographic computation comprises a digital signature generating function and the authentication data comprises a digital signature.

14. The electronic device of claim 1 , wherein the cryptographic computation is based, at least in part, on (a) data relating to an authentication computation and (b) electronic device information, wherein the electronic device information comprises one or both of: (i) information suitable for identifying the electronic device and (ii) information specifying at least part of a configuration of the electronic device.

15. The electronic device of claim 14 , wherein the information suitable for identifying the electronic device is based, at least in part, on at least one of a device MAC address; or a device IMEI, or wherein the information specifying at least part of a configuration of the electronic device is based, at least in part, on at least one of: the whole or a part of an operating system of the electronic device; a version or type of the electronic device; and an operating system application token provided by a platform application store stored on the electronic device.

16. A system comprising an electronic device, a terminal, and an authorization entity, wherein the electronic device comprises:

one or more processors that:

perform at least one secure multiparty cryptographic process using a plurality of modules that jointly generate authentication data based at least in part on a message, wherein each of said modules performs that module's part of said secure multiparty cryptographic process using secure data unique to each module that is not shared outside that module; and update the respective secure data of at least two of the modules,

wherein the respective secure data of a first module of the at least two of the modules is updated using a modification value, each of the at least two of the modules determine the modification value, wherein the modification value is determined using at least a public key associated with the first module of the at least two of the modules and at least a public key associated with the second module of the at least two of the modules, and

wherein the respective secure data of a second module of the at least two of the module is updated using the modification value, and

wherein the updated secure data is arranged so that, for each possible value of the operation data, performance of the secure multiparty computation using the updated secure data generates the same authentication data as performance of the secure multiparty computation using the secure data prior to the step of updating; and

an output interface that transmits to the terminal the message and the authentication data;

the terminal comprises:

an input interface that receives the message and the authentication data from the electronic device; and

an output interface that transmits to the message and the authentication data to the authorization entity; and

the authorization entity comprises:

an input interface that receives the message and the authentication data from the terminal; and

a processor that performs an authorization process using the received message and the authentication data in order authorize the electronic device.

17. The system of claim 16 , wherein the authentication data comprises at least one of a message authentication code (MAC), a hash, an authorization request cryptogram (ARQC) and a digital signature.