US Patent 11095634 User authentication using multi-party computation and public key cryptography

Techniques are disclosed relating to user authentication using multi-party computation and public key cryptography. In some embodiments, a client system may receive, from a server system, an authentication challenge that includes a first partial signature value. The client system may access key-pair information that includes, for a server key-pair, a server public key and a second component of a server private key, where the server system has access to a first component of the server private key. The client system may then generate a second partial signature value using the second component of the server private key but not an entirety of the server private key, and may generate a final signature value based on the first and second partial signature values. Using the final signature value, the client system may then determine whether the authentication challenge was sent by the server system.