Minimal disclosure credential verification and revocation
The subject disclosure is directed towards credential verification for accessing a service provider. A user may prove to the service provider the validity of the credential by communicating a non-revocation component that is based upon a prime-order cryptographic group without a bilinear pairing. In order to authenticate the user, a verification mechanism within an identity management system applies private cryptographic data, including a verifier-designated private key to the non-revocation component, which proves that the user's identity and therefore, the credential is not revoked. The presentation proof includes a hash value that is computed using the credential's commitment and the prime-order cryptographic group. By verifying that the hash value was computed using that commitment, the verification mechanism validates the credential and permits access to the service provider.
1. A computer-implemented method for execution by a verifier for a service provider, the method comprising:
receiving from a computing device of a user a verification request for completing an electronic transaction with an online property included in the service provider;
accessing a non-revocation component stored in the verification request and comprising a user identifier of the user, the non-revocation component corresponding to a minimal disclosure credential that is associated with identifying the computing device, the non-revocation component corresponding to a prime-order cryptographic group-based scheme including an accumulator computed using the user identifier, a verifier-designated cryptographic key corresponding to the verifier and at least one valid identifier or at least one revoked identifier, the user identifier being generated by a third party identity provider such that the user remains anonymous;
granting or denying the electronic transaction by determining the user identifier's membership or non-membership in the accumulator based on applying the verifier-designated cryptographic key to the non-revocation component to verify that the non-revocation component is computed using the verifier-designated cryptographic key; and
in response to determining that the minimal disclosure credential is a prior credential being used to complete the electronic transaction while another minimal disclosure credential associated with the computing device is a pending credential, updating the non-revocation component to revoke the minimal disclosure credential and the other minimal disclosure credential, and generating a new minimal disclosure credential associated with the computing device by accumulating at least the user identifier of the minimal disclosure credential into the accumulator.
2. The method of claim 1 further comprising validating a commitment for a revocation attribute corresponding to the user identifier.
3. The method of claim 1 further comprises if the user identifier is a member of the accumulator comprising the at least one valid identifier or if the user identifier is a non-member of the accumulator comprising the at least one revoked identifier, instructing the service provider to grant the verification request.
4. The method of claim 1 further comprises if the user identifier is a non-member of the accumulator comprising the at least one valid identifier or if the user identifier is a member of the accumulator comprising the at least one revoked identifier, instructing the service provider to deny the verification request.
5. The method of claim 1 further comprising generating a challenge based upon a prime-order cyclic group of the non-revocation component, processing a witness to an identifier and verifying non-revocation of the identifier based upon the witness and a commitment to the identifier that is computed using the challenge.
6. The method of claim 1 , wherein applying the verifier-designated cryptographic key further comprises using a verifier-designated private key, based upon a discrete logarithmic group, to prove non-revocation of the minimal disclosure credential.
7. The method of claim 1 , wherein applying the verifier-designated cryptographic key further comprises verifying a presentation proof generated for the minimal disclosure credential by using a prime-order cyclic subgroup construction or an elliptical curve construction of the prime-order cryptographic group to compute mathematical numbers for comparison with components of the presentation proof.
8. The method of claim 1 , wherein applying the verifier-designated cryptographic key further comprises generating the verifier-designated cryptographic key using a standardized cryptographic group, and applying the verifier-designated cryptographic key to the non-revocation component to determine validity of the minimal disclosure credential.
9. The method of claim 1 further comprising generating a public cryptographic key and a private cryptographic key from a prime-order cyclic subgroup or elliptic curve.
10. An apparatus implemented in hardware comprising:
a verifier comprising logic stored in hardware memory and executed on a logic circuit, the verifier being operative to:
receive from a computing device of a user a verification request for completing an electronic transaction with an online property included in a service provider;
access a non-revocation component stored in the verification request and comprising a user identifier of the user, the non-revocation component corresponding to a minimal disclosure credential that is associated with identifying the computing device, the non-revocation component corresponding to a prime-order cryptographic group-based scheme including an accumulator computed using the user identifier, a verifier-designated cryptographic key corresponding to the verifier and at least one valid identifier or at least one revoked identifier, the user identifier being generated, by a third party identity provider, such that the user remains anonymous;
grant or deny the electronic transaction by determining the user identifier's membership or non-membership in the accumulator based on applying the verifier-designated cryptographic key to the non-revocation component to verify that the non-revocation component is computed using the verifier-designated cryptographic key; and
in response to determining that the minimal disclosure credential is a prior credential being used to complete the electronic transaction while another minimal disclosure credential associated with the computing device is a pending credential, update the non-revocation component to revoke the minimal disclosure credential and the other minimal disclosure credential, and generate a new minimal disclosure credential associated with the computing device by accumulating at least the user identifier of the minimal disclosure credential into the accumulator.
11. The apparatus of claim 10 , the verifier being further operative to validate a commitment for a revocation attribute corresponding to a user identifier.
12. The apparatus of claim 10 , the verifier being further operative to instruct the service provider to grant the verification request if the user identifier is a member of the accumulator comprising the at least one valid identifier or if the user identifier is a non-member of the accumulator comprising the at least one revoked identifier.
13. The apparatus of claim 10 , the verifier being further operative to instruct the service provider to deny the verification request if the user identifier is a non-member of the accumulator comprising the at least one valid identifier or if the user identifier is a member of the accumulator comprising the at least one revoked identifier.
14. The apparatus of claim 10 , the verifier being further operative to generate a challenge based upon a prime-order cyclic group of the non-revocation component, processing a witness to an identifier and verify non-revocation of the identifier based upon the witness and a commitment to the identifier that is computed using the challenge.
15. The apparatus of claim 10 , wherein applying the verifier-designated cryptographic key includes the verifier being further operative to use a verifier-designated private key, based upon a discrete logarithmic group, to prove non-revocation of the minimal disclosure credential.
16. The apparatus of claim 10 , wherein applying the verifier-designated cryptographic key includes the verifier being further operative to verify a presentation proof generated for the minimal disclosure credential by using a prime-order cyclic subgroup construction or an elliptical curve construction of the prime-order cryptographic group to compute mathematical numbers for comparison with components of the presentation proof.
17. The apparatus of claim 10 , wherein applying the verifier-designated cryptographic key includes the verifier being further operative to generate the verifier-designated cryptographic key using a standardized cryptographic group, and applying the verifier-designated cryptographic key to the non-revocation component to determine validity of the minimal disclosure credential.
18. The apparatus of claim 10 , the verifier being further operative to generate a public cryptographic key and a private cryptographic key from a prime-order cyclic subgroup or elliptic curve.
19. Computer-readable storage hardware having computer-executable instructions, which when executed, cause a computer to perform steps, comprising:
receiving from a computing device of a user a verification request for completing an electronic transaction with an online property included in a service provider;
accessing a non-revocation component stored in the verification request and comprising a user identifier of the user, the non-revocation component corresponding to a minimal disclosure credential that is associated with identifying the computing device, the non-revocation component corresponding to a prime-order cryptographic group-based scheme including an accumulator computed using the user identifier, a verifier-designated cryptographic key corresponding to the verifier and at least one valid identifier or at least one revoked identifier, the user identifier being generated, by a third party identity provider, such that the user remains anonymous;
granting or denying the electronic transaction by determining the user identifier's membership or non-membership in the accumulator based on applying the verifier-designated cryptographic key to the non-revocation component to verify that the non-revocation component is computed using the verifier-designated cryptographic key; and
in response to determining that the minimal disclosure credential is a prior credential being used to complete the electronic transaction while another minimal disclosure credential associated with the computing device is a pending credential, updating the non-revocation component to revoke the minimal disclosure credential and the other minimal disclosure credential, and generating a new minimal disclosure credential associated with the computing device by accumulating at least the user identifier of the minimal disclosure credential into the accumulator.
20. The computer-readable storage hardware of claim 19 having further computer-executable instructions comprising:
instructing the service provider to deny the verification request if the user identifier is a non-member of the accumulator comprising the at least one valid identifier or if the user identifier is a member of the accumulator comprising the at least one revoked identifier, or
instructing the service provider to grant the verification request if the user identifier is a member of the accumulator comprising the at least one valid identifier or if the user identifier is a non-member of the accumulator comprising the at least one revoked identifier.