In this blog post we give some information about my implementation of a C# triple-DES stream cipher using the ANSI X9.17 pseudorandom number generator of 5.11 Algorithm in the Handbook of Applied Cryptography by Alfred J. Menezes, ET AL. page 173. This is about as close as I can come to a one time pad (perfect security) utilizing a triple-DES based function for key generation. I suspect the security is pretty tight as long as one does not stupidly reuse a key. Recall from my previous blogs on the ANSI X9.17 matrix cipher that key space is 168-bits for triple-DES in E-D-E mode and an additional 128-bits in other key parameters for a total of 296-bits.
It would be nice if the index of coincidence was 0, but this index is probably satisfactory.
Numerical Explorations 