||This article relies largely or entirely upon a single source. (June 2010)
Cohen's cryptosystem is a public-key cryptosystem proposed in 1998 by Bram Cohen.
In Cohen's cryptosystem, private key is a positive integer .
The algorithm uses public-keys defined as follows:
Generate random integers chosen randomly and uniformly between and . Where is some bound.
Let and generate random integers chosen randomly and uniformly between and .
Encrypting a bit
To encrypt a bit Alice randomly adds public keys and multiplies the result by either 1 (if she wishes to send a 0) or by −1 (if she wishes to send a 1) to obtain the ciphertext .
To de-crypt, Bob computes
It is easy to see that if then . However, if then . Hence Bob can read the bit sent by Alice on the most significant bit of h.
- ^ Bram Cohen. "Simple Public Key Encryption". Archived from the original on October 7, 2011.