Privacy-preserving identity attribute verification using policy tokens
Methods and systems for privacy-preserving identity attribute verification are presented. During an interaction between a relying entity and a user, a relying entity computer can transmit a policy token to a user device. The policy token may indicate the information needed by the relying entity in order to perform the interaction. The user device can verify the policy token, then use the policy token in conjunction with an identity token to generate a zero-knowledge proof. The user device may transmit the zero-knowledge proof to an identity service provider computer. The identity service provider computer may verify the zero-knowledge proof, then generate a verification message. The identity service provider computer may sign the verification message and transmit the signed verification message to the relying entity computer. The relying entity computer may verify the verification message and complete the interaction with the user.
1 . A method comprising:
providing, by a relying party computer to a user device, a policy token, wherein the user device generates a zero-knowledge proof using the policy token and a set of identity attributes stored on the user device and transmits the zero-knowledge proof to an identity service provider computer, which verifies the zero-knowledge proof and generates a verification message;
receiving, by the relying party computer, the verification message; and
performing, by the relying party computer, an interaction with the user device based on the verification message.
2 . The method of claim 1 , wherein the policy token is cryptographically signed using a private key corresponding to a token server computer, and wherein the user device verifies the policy token using a public key corresponding to the token server computer.
3 . The method of claim 1 , further comprising:
receiving, by the relying party computer from the identity service provider computer, the policy token.
4 . The method of claim 1 , further comprising:
transmitting, by the relying party computer to the user device, a nonce along with the policy token; and
receiving, by the relying party computer from the identity service provider computer, the nonce in the verification message.
5 . The method of claim 4 , wherein the nonce and a verification result in the verification message are signed using a secret key of the identity service provider computer.
6 . The method of claim 5 , further comprising:
verifying, by the relying party computer, the signed nonce and the verification result in the verification message with a public key corresponding to the secret key.
7 . The method of claim 1 , wherein the zero-knowledge proof is used to verify that a user of the user device is of a certain age.
8 . The method of claim 1 , wherein the identity service provider computer verifies the zero-knowledge proof using two sub-verifiers.
9 . The method of claim 1 , wherein the policy token is provided by the relying party computer to the user device via NFC or a QR code.
10 . The method of claim 1 , wherein the policy token comprises one or more predicates, wherein each predicate corresponds to one or more identity attributes from the set of identity attributes, and wherein the zero-knowledge proof corresponds to the one or more predicates and the set of identity attributes.
11 . A relying party computer comprising:
a processor; and
a non-transitory computer readable medium coupled to the processor, the non-transitory computer readable medium comprising code, executable by the processor, for implementing a method comprising:
providing, to a user device, a policy token, wherein the user device generates a zero-knowledge proof using the policy token and a set of identity attributes stored on the user device and transmits the zero-knowledge proof to an identity service provider computer, which verifies the zero-knowledge proof and generates a verification message;
receiving the verification message; and
performing, by the relying party computer, an interaction with the user device based on the verification message.
12 . The relying party computer of claim 11 , wherein the policy token is cryptographically signed using a private key corresponding to a token server computer.
13 . The relying party computer of claim 11 , wherein the method further comprises:
receiving, by the relying party computer from the identity service provider computer, the policy token.
14 . The relying party computer of claim 11 , wherein the method further comprises:
transmitting, by the relying party computer to the user device, a nonce along with the policy token; and
receiving, by the relying party computer from the identity service provider computer, the nonce in the verification message.
15 . The relying party computer of claim 11 , wherein the policy token is provided by the relying party computer to the user device via NFC or a QR code.
16 . The relying party computer of claim 11 , wherein the policy token comprises one or more predicates, wherein each predicate corresponds to one or more identity attributes from the set of identity attributes, and wherein the zero-knowledge proof corresponds to the one or more predicates and the set of identity attributes.
17 . A system comprising:
a relying party computer comprising
a processor, and
a non-transitory computer readable medium coupled to the processor, the non-transitory computer readable medium comprising code, executable by the processor, for implementing a method comprising
providing, to a user device, a policy token, wherein the user device generates a zero-knowledge proof using the policy token and a set of identity attributes stored on the user device and transmits the zero-knowledge proof to an identity service provider computer, which verifies the zero-knowledge proof and generates a verification message,
receiving the verification message, and
performing, by the relying party computer, an interaction with the user device based on the verification message; and
the user device.
18 . The system of claim 17 , further comprising:
the identity service provider computer.
19 . The system of claim 17 , wherein the method further comprises:
transmitting, by the relying party computer to the user device, a nonce along with the policy token; and
receiving, by the relying party computer from the identity service provider computer, the nonce in the verification message.
20 . The system of claim 17 , wherein the policy token comprises one or more predicates, wherein each predicate corresponds to one or more identity attributes from the set of identity attributes, and wherein the zero-knowledge proof corresponds to the one or more predicates and the set of identity attributes.