Multi Utility Program for Bitcoin
This program uses no external libraries besides the one in the STL. That means established hash algorithms (SHA256 and RIPEMD160), arbitrary precision integers, and elliptic curve cryptography are implemented from scratch. This is obviously a bad idea which you should never do in practice, but I am doing so in the interests of paranoia (no rigged secret key generation), intellectual exercise (reading papers and converting to code), fun, and maybe profit!.