I have constructed a stream cipher from a secure hash algorithm and a HMAC. Here is a brief description of the algorithm: Let: (Actually Objective-C styled pseudo code) ...
(Already asked the same question on stackoverflow but I was told to better ask here. http://stackoverflow.com/questions/17527192/one-time-pad-with-dh-and-cryptographic-hash-function) I know: Never do ...
A comment on another question made me wonder about something: Assume you're on a rather constrained platform — say, a low-end embedded device — with no built-in crypto capabilities, ...
A few years ago I devised a symmetric-key system that worked like so: ...