Cohen's cryptosystem
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Cohen's cryptosystem[1] is a public-key cryptosystem proposed in 1998 by Bram Cohen.
Key generation
[edit]In Cohen's cryptosystem, a 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 .
Define .
Encrypting a bit
[edit]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 .
De-cryption
[edit]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.
References
[edit]- ^ Bram Cohen. "Simple Public Key Encryption". Archived from the original on October 7, 2011.