New answers tagged pseudo-random-generator
You can use the well established TLS (Transport Layer Security) protocol to achieve the first three properties and modify it to include a digital signature for non-repudiation*. However, strictly speaking, non-repudiation requires the use of certificates from a CA so that the signature can be verified by any third party.
There are a reasonable number of assumptions I'm going to have to make to try and answer this question. For perfect security, we require that the keystream is truely random, and never reused (OTP,shannon). I've decided to add in a short answer here: STOP! There's absolutely no need to use a reduced character set thing anyway - you can just use your random ...
Top 50 recent answers are included