fn new_cipher(key byte) ?Cipher
new_cipher creates and returns a new Cipher. The key argument should be the RC4 key, at least 1 byte and at most 256 bytes.
fn (mut c Cipher) reset()
reset zeros the key data and makes the Cipher unusable.good to com Deprecated: Reset can't guarantee that the key will be entirely removed from the process's memory.
fn (mut c Cipher) xor_key_stream(mut dst byte, mut src byte)
xor_key_stream sets dst to the result of XORing src with the key stream. Dst and src must overlap entirely or not at all.