Mercurial > projects > dcrypt
view dcrypt/crypto/modes/CTR.d @ 8:23c62e28b3a4
Reworked symmetric cipher classes to have SymmetricCipher as their superclass, and follow the general interface of init(), process(), etc. Made sure everything still passed test vectors. Removed Cipher class. I'll worry about that shit when we support something other than symmetric ciphers.
author | Thomas Dixon <reikon@reikon.us> |
---|---|
date | Mon, 18 Aug 2008 01:14:37 -0400 |
parents | 0e08791a1418 |
children | cd376996cdb3 |
line wrap: on
line source
/** * This file is part of the dcrypt project. * * Copyright: Copyright (C) dcrypt contributors 2008. All rights reserved. * License: MIT * Authors: Thomas Dixon */ module dcrypt.crypto.modes.CTR; import dcrypt.crypto.BlockCipher; import dcrypt.crypto.params.ParametersWithIV; /** This class implements the counter (CTR/SIC/ICM) block mode, treating the counter as a big endian integer. */ class CTR : BlockCipher { private BlockCipher m_cipher; private ubyte[] iv, counter, counterOutput; private bool initialized = false; /** * Params: * cipher = Block cipher to wrap. */ this (BlockCipher cipher) { m_cipher = cipher; } /** Returns: The underlying cipher we are wrapping. */ BlockCipher cipher() { return m_cipher; } char[] name() { return m_cipher.name~"/CTR"; } /** * Throws: dcrypt.crypto.errors.InvalidParameterError if params aren't * an instance of dcrypt.crypto.params.ParametersWithIV. */ void init(bool encrypt, CipherParameters params) { ParametersWithIV ivParams = cast(ParametersWithIV)params; if (!ivParams) throw new InvalidParameterError( name()~": Block mode requires IV (use ParametersWithIV)"); if (ivParams.iv.length != blockSize) throw new InvalidParameterError( name()~": IV must be same length as cipher block size"); m_cipher.init(true, ivParams.parameters); iv = ivParams.iv[0..blockSize]; counter = new ubyte[blockSize]; counter[] = iv; counterOutput = new ubyte[blockSize]; initialized = true; } ubyte[] process(void[] input_) { if (!initialized) throw new NotInitializedError( name()~": Block mode not initialized"); ubyte[] input = cast(ubyte[]) input_; // Encrypt the counter counterOutput[] = m_cipher.process(counter); // XOR output with plaintext to create ciphertext for (int i = 0; i < counter.length; i++) counterOutput[i] ^= input[i]; // Increment the counter for (int i = counter.length-1; i >= 0; i--) if (++counter[i]) break; return counterOutput; } uint blockSize() { return m_cipher.blockSize; } void reset() { counter[] = iv; m_cipher.reset(); } }