Abstract: A method, system and computer program is provided for protecting against one or more security attacks from third parties directed at obtaining user credentials on an unauthorized basis, as between a client computer associated with a user and a server computer is provided. The server computer defines a trusted Public Key Cryptography utility for use on the client computer. The Public Key Cryptography utility is operable to perform one or more cryptographic operations consisting of encrypting/decrypting data, authenticating data, and/or authenticating a sender, decrypting and/or verifying data. The user authenticates to the Public Key Cryptography utility, thereby invoking the accessing of user credentials associated with the user, as defined by the server computer. The Public Key Cryptography Utility facilitates the communication of the user credentials to the server computer, whether directly or indirectly via an authentication agent, the server computer thereby authenticating the user.