GregNews on RSA

[Hartmut Pilch <phm@a2e.de>]

Bernhard Kaindl's summary of the cyberlaw rsa page found its way into
GregNews (http://swpat.ffii.org/players/aharonian):

    -  AN ANALYSIS OF THE EXPIRED RSA CRYPTOGRAPHY PATENT


A Web page, http://www.cyberlaw.com/rsa.html, argues that the RSA patent,
now expired, was obviousness enough in light of the prior art to not be
patentable, for being a variant of the Pohlig-Hellman algorithm which
existed before RSA.

   +---------------------------------------------------------------------+
   |  Comparison of RSA and  |                        |                  |
   |     Pohlig-Hellman      |                        |                  |
   |-------------------------+------------------------+------------------|
   |                         |  RSA System            |  Pohlig-Hellman  |
   |-------------------------+------------------------+------------------|
   |Encryption Operation     | C = M^e mod n          |C = M^e mod p     |
   |-------------------------+------------------------+------------------|
   |Decryption Operation     | M = C^e mod n          |M = C^e mod p     |
   |-------------------------+------------------------+------------------|
   |modulus                  | p * q (prime numbers)  |p (prime number)  |
   |-------------------------+------------------------+------------------|
   |Encryption exponent (e)  | e relatively prime to  |e relatively prime|
   |                         | (p-1)*(q-1)            |to (p-1)          |
   |-------------------------+------------------------+------------------|
   |Decryption exponent (d)  | d = e^-1 mod ((p-1)*   |d = e^-1 mod (p-1)|
   |                         | (q-1))                 |                  |
   +---------------------------------------------------------------------+

-- 
Hartmut Pilch, FFII & Eurolinux Alliance              tel. +49-89-18979927
Protecting Innovation against Patent Inflation       http://swpat.ffii.org/
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