The Massey–Omura Cryptosystem: A Public Key Commutative encryption Method
I love reading classic papers and the patents that have helped build the Internet. One classic patent was written by James Massey and Jim K. Omura created the Massey–Omura Cryptosystem in 1982 [1]. It took over three years to be assigned and was assigned to Omnet Associates [here]:
It uses exponentiation in the Galois field GF(2^n) for both the encryption and decryption functions. In this, if we have a message of M, the encryption is:
and
This are operated on with the Galois field. For this we define e
within:
and:
The decryption exponent d is defined as:
This works because the multiplicative group of the Galois field GF(2^n) has order 2^n−1, and where Lagrange’s theorem defines that m^{de}=m for all the values of m in GF(2^n).
The coding is here [link]:
import libnum
import random
import sysfrom Crypto.Util.number import getPrime
from Crypto.Random import get_random_bytes
def chunkstring(string…
