On Wed, Oct 9, 2019 at 10:05 PM Keith F. Lynch <kfl@keithlynch.net> wrote:
Some years ago it occurred to me that exclusive-oring a text with a subset of the square roots, in binary, of the first N primes, followed by the above scrambling algorithm (in ASCII order), followed by the same exclusive-oring again, would be a pretty good encryption algorithm. Does anyone disagree?
The scrambling is irrelevant if the ciphertext has length N and the square roots of those N primes are GF(2)-linearly independent. Just apply Gaussian elimination and you've reduced the cipher to a one-time pad. If N is less than the length of the ciphertext, then there will likely be exploitable statistical correlations. -- Mike Stay - metaweta@gmail.com http://math.ucr.edu/~mike https://reperiendi.wordpress.com