DIMACS TR: 2001-37
Delegation of Cryptographic Servers for Capture-Resilient Devices
Authors: Philip MacKenzie and Michael K. Reiter
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 proactive security for the
device's private key, i.e., proactive updates to the device and
servers to eliminate any threat of offline password guessing attacks
due to previously compromised servers.
Paper Available at:
ftp://dimacs.rutgers.edu/pub/dimacs/TechnicalReports/TechReports/2001/2001-37.ps.gz
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