Initial project import

tools/v/vlib/crypto/cipher/cipher.v

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+// The source code refers to the go standard library, which will be combined with AES in the future.
+
+module cipher
+
+// A Block represents an implementation of block cipher
+// using a given key. It provides the capability to encrypt
+// or decrypt individual blocks. The mode implementations
+// extend that capability to streams of blocks.
+pub interface Block {
+	block_size int // block_size returns the cipher's block size.
+	encrypt(mut dst []u8, src []u8) // Encrypt encrypts the first block in src into dst.
+	// Dst and src must overlap entirely or not at all.
+	decrypt(mut dst []u8, src []u8) // Decrypt decrypts the first block in src into dst.
+	// Dst and src must overlap entirely or not at all.
+}
+
+// A Stream represents a stream cipher.
+pub interface Stream {
+mut:
+	// xor_key_stream XORs each byte in the given slice with a byte from the
+	// cipher's key stream. Dst and src must overlap entirely or not at all.
+	//
+	// If len(dst) < len(src), xor_key_stream should panic. It is acceptable
+	// to pass a dst bigger than src, and in that case, xor_key_stream will
+	// only update dst[:len(src)] and will not touch the rest of dst.
+	//
+	// Multiple calls to xor_key_stream behave as if the concatenation of
+	// the src buffers was passed in a single run. That is, Stream
+	// maintains state and does not reset at each xor_key_stream call.
+	xor_key_stream(mut dst []u8, src []u8)
+}
+
+// A BlockMode represents a block cipher running in a block-based mode (CBC,
+// ECB etc).
+pub interface BlockMode {
+	block_size int // block_size returns the mode's block size.
+	crypt_blocks(mut dst []u8, src []u8) // crypt_blocks encrypts or decrypts a number of blocks. The length of
+	// src must be a multiple of the block size. Dst and src must overlap
+	// entirely or not at all.
+	//
+	// If len(dst) < len(src), crypt_blocks should panic. It is acceptable
+	// to pass a dst bigger than src, and in that case, crypt_blocks will
+	// only update dst[:len(src)] and will not touch the rest of dst.
+	//
+	// Multiple calls to crypt_blocks behave as if the concatenation of
+	// the src buffers was passed in a single run. That is, BlockMode
+	// maintains state and does not reset at each crypt_blocks call.
+}
+
+// AEAD provides an authenticated encryption with associated data for encryption (decryption).
+pub interface AEAD {
+	// nonce_size returns the size of nonce (in bytes) used by this AEAD that must be
+	// passed to `.encrypt` or `.decrypt`.
+	nonce_size() int
+	// overhead returns the maximum difference between the lengths of a plaintext and its ciphertext.
+	overhead() int
+	// encrypt encrypts and authenticates the provided plaintext along with the nonce and
+	// additional data in `ad`. The nonce must be `nonce_size()` bytes long and unique
+	// for all time, for a given key. It returns encrypted (and authenticated) ciphertext bytes
+	// where its encoded form is up to implementation and not dictated by the interfaces.
+	// Commonly, its contains encrypted text plus some authentication tag, and maybe some other bytes.
+	encrypt(plaintext []u8, nonce []u8, ad []u8) ![]u8
+	// decrypt decrypts and authenticates (verifies) the provided ciphertext along with a nonce, and
+	// additional data. The nonce must be `nonce_size()` bytes long and both it and the additional data
+	// must match the value passed to `encrypt`.
+	// Its returns the verified plaintext on success, or errors on fails.
+	decrypt(ciphertext []u8, nonce []u8, ad []u8) ![]u8
+}
+
+// Utility routines
+
+// fn dup(p []u8) []u8 {
+// 	q := make([]u8, p.len)
+// 	copy(mut q, p)
+// 	return q
+// }