# Class type Cryptokit.Stream.stream_cipher

    class type stream_cipher = object .. end

Abstract interface for a stream cipher.

    method transform : bytes -> int -> bytes -> int -> int -> unit

`transform src spos dst dpos len` encrypts or decrypts `len` characters, read from byte array `src` starting at position `spos`. The resulting `len` characters are stored in byte array `dst` starting at position `dpos`.

    method wipe : unit

Erase the internal state of the stream cipher, such as all key-dependent material.