Techniques for user authentication based upon an asymmetric key pair having a public key and a split private key are provided. A first portion of the split private key is generated based upon multiple factors under control of the user. The factors include a password. A challenge is cryptographically combined with a first one of the multiple factors, but not the user password, to form a first message. The first message is transformed with the generated first portion to form a second message, which is then sent to an authentication entity. The sent second message is transformed to authenticate the user by proving direct verification of user control of the first factor.