US Patent 10356088 User authentication based on multiple asymmetric cryptography key pairs

An ID service provisioned on a server interacts with a corresponding ID app installed on a user device such as a smart phone for secure user authentication (login). A user acquires two asymmetric encryption keys pairs. One of the private keys is secured on SIM on the user device, and the other one stored in the ID app on the user device. At login attempt, the ID service generates two random challenge messages, and encrypts each of them with one of the public keys. Decryption of one challenge is conducted by the SIM and decryption of the other is done by the ID app. A token based on the two decrypted challenge results is returned to the ID service. Alternatively, a single challenge can be double-wrapped with the two keys. The verifies the results and enables secure login without requiring a password.