Module chacha

Implementation of the ChaCha cryptographic primitives.
More details can be seen at https://en.wikipedia.org/wiki/Salsa20

Functions

• chacha_block
  Do one ChaCha round on the input data.
• chacha_increment_counter
  Increment the 64-bit counter of the internal ChaCha20 state by 1. Returns false if it overflows, true otherwise.
• chacha_init
  Initialize the ChaCha internal state, with a 256-bit key and 64-bit nonce.