Adding standalone RSA code

[Colin Percival]

Tim Robbins wrote:
> Can you be a little more specific about what your library supports?

RSA -- key generation, signing, verification, encryption, decryption.

> What
> format does it expect keys to be in? What format does it store signatures in?

Everything is an integer of keylen/8 bytes.  The value of the integer
x[] is x[0] + x[1] * 2^8 + x[2] * 2^16 + ...

Keeping track of details -- like the keylength, or allocating temporary
working space -- is left up to the caller; my library functions take
a set of pointers to arrays of bytes, integer length(s), and a pointer
to preallocated working space (of size depending upon the key length).

Colin Percival