Delegation of cryptographic servers for capture-resilient devices

Abstract. A device that performs private key operations (signatures or decryptions), and whose private key operations are protected by a password, can be immunized against offline dictionary attacks in case of capture by forcing the device to confirm a password guess with a designated remote server in order to perform a private key operation. Recent proposals for achieving this allow untrusted servers and require no server initialization per device. In this paper we extend these proposals to enable dynamic delegation from one server to another; i.e., the device can subsequently use the second server to secure its private key operations. One application is to allow a user who is traveling to a foreign country to temporarily delegate to a server local to that country the ability to confirm password guesses and aid the user’s device in performing private key operations, or in the limit, to temporarily delegate this ability to a token in the user’s possession. Another application is...

• Type: Conference
• Year: 2001
• Where: CCS
• Authors: Philip D. MacKenzie, Michael K. Reiter
• Keywords: CCS 2001, Device’s Private Key, Offline Dictionary Attacks, Private Key Operations, Security Privacy