cipher

type Block interface {
	// BlockSize returns the cipher's block size.
	BlockSize() int

	// Encrypt encrypts the first block in src into dst.
	// Dst and src may point at the same memory.
	Encrypt(dst, src []byte)

	// Decrypt decrypts the first block in src into dst.
	// Dst and src may point at the same memory.
	Decrypt(dst, src []byte)
}

type BlockMode interface {
	// BlockSize returns the mode's block size.
	BlockSize() int

	// CryptBlocks encrypts or decrypts a number of blocks. The length of
	// src must be a multiple of the block size. Dst and src may point to
	// the same memory.
	CryptBlocks(dst, src []byte)
}

type Stream interface {
	// XORKeyStream XORs each byte in the given slice with a byte from the
	// cipher's key stream. Dst and src may point to the same memory.
	XORKeyStream(dst, src []byte)
}

type StreamReader struct {
	S Stream
	R io.Reader
}

type StreamWriter struct {
	S   Stream
	W   io.Writer
	Err error
}