Browse Prior Art Database

Network Specification of Short Length RSA Private Keys

IP.com Disclosure Number: IPCOM000118351D
Original Publication Date: 1996-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Johnson, DB: AUTHOR

Abstract

In some networks using RSA cryptography, it may be desirable to set a limit to the length of an RSA private key exponent for performance reasons.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 76% of the total text.

Network Specification of Short Length RSA Private Keys

      In some networks using RSA cryptography, it may be desirable to
set a limit to the length of an RSA private key exponent for
performance reasons.

      In (*), it is pointed out that sometimes it is desirable for a
short RSA private key exponent to be used.  It shows that an RSA
private key exponent of about 1/4 the size of the modulus is
insecure, assuming  the public key exponent is the size of the RSA
modulus.

      This invention is to allow the specification by a network
security administrator of the length of an RSA private key exponent
so that all users in a group will use this length which will result
in a performance improvement when using these private keys.  This
complements the ability of a network security administrator to
specify a short value (for example, 3) for the RSA public key
exponent for performance reasons.  That is, a network security
administrator now is able to specify one of the following for RSA
keys:
  1.  Random Public Key and Random-looking Private Key
       (no performance optimization, both private key and
       public key operations take Big-O(N**3) time, where
       N is size of RSA modulus).
  2.  Short Public Key and Random-looking Private Key
       (public key operations are fast: private key takes
       Big-O(N**3) time, but public key takes Big-O(N**2) time).
  3.  Random-looking Public Key and Short Private Key (pri...