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142 lines
5.3 KiB
142 lines
5.3 KiB
#ifndef _BLOWFISH_H_
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#define _BLOWFISH_H_
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//=============================================================================
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//
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// File : ablowfish.h
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// Creation date : Wed Jan 13 2005 02:04:10 CEST by Szymon Stefanek
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//
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// This file is part of the KVirc irc client distribution
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// Copyright (C) 2005 Szymon Stefanek (pragma at kvirc dot net)
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//
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// This program is FREE software. You can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your opinion) any later version.
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//
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// This program is distributed in the HOPE that it will be USEFUL,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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// See the GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, write to the Free Software Foundation,
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// Inc. ,51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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//=============================================================================
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//
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// This code is adapted from the MircCryption engine suite by Dark Raichu
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// Original comments follow.
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//
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//---------------------------------------------------------------------------
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// The implementation of blowfish for CBC mode is from
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// http://www.thecodeproject.com/cpp/blowfish.asp by George Anescu
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// I removed exception handling, so it is callers responsibility to insure
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// that strings are length multiples of 8 bytes
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// -mouser 1/08/05
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//---------------------------------------------------------------------------
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//
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// BLOWFISH ENCRYPTION ALGORITHM
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//
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// Implementation of Bruce Schneier's BLOWFISH algorithm from "Applied
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// Cryptography", Second Edition.
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//
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// Encryption and Decryption of Byte Strings using the Blowfish Encryption Algorithm.
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// Blowfish is a block cipher that encrypts data in 8-byte blocks. The algorithm consists
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// of two parts: a key-expansion part and a data-ancryption part. Key expansion converts a
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// variable key of at least 1 and at most 56 bytes into several subkey arrays totaling
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// 4168 bytes. Blowfish has 16 rounds. Each round consists of a key-dependent permutation,
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// and a key and data-dependent substitution. All operations are XORs and additions on 32-bit words.
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// The only additional operations are four indexed array data lookups per round.
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// Blowfish uses a large number of subkeys. These keys must be precomputed before any data
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// encryption or decryption. The P-array consists of 18 32-bit subkeys: P0, P1,...,P17.
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// There are also four 32-bit S-boxes with 256 entries each: S0,0, S0,1,...,S0,255;
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// S1,0, S1,1,...,S1,255; S2,0, S2,1,...,S2,255; S3,0, S3,1,...,S3,255;
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//
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// The Electronic Code Book (ECB), Cipher Block Chaining (CBC) and Cipher Feedback modes
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// are used:
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//
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// In ECB mode if the same block is encrypted twice with the same key, the resulting
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// ciphertext blocks are the same.
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//
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// In CBC Mode a ciphertext block is obtained by first xoring the
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// plaintext block with the previous ciphertext block, and encrypting the resulting value.
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//
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// In CFB mode a ciphertext block is obtained by encrypting the previous ciphertext block
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// and xoring the resulting value with the plaintext
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//
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// The previous ciphertext block is usually stored in an Initialization Vector (IV).
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// An Initialization Vector of zero is commonly used for the first block, though other
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// arrangements are also in use.
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//
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#include "kvi_settings.h"
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#ifdef COMPILE_CRYPT_SUPPORT
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//Block Structure
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struct SBlock
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{
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//Constructors
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SBlock(unsigned int l=0, unsigned int r=0) : m_uil(l), m_uir(r) {}
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//Copy Constructor
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SBlock(const SBlock& roBlock) : m_uil(roBlock.m_uil), m_uir(roBlock.m_uir) {}
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SBlock& operator^=(SBlock& b) { m_uil ^= b.m_uil; m_uir ^= b.m_uir; return *this; }
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unsigned int m_uil, m_uir;
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};
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class BlowFish
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{
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public:
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enum { ECB=0, CBC=1, CFB=2 };
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//Constructor - Initialize the P and S boxes for a given Key
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BlowFish(unsigned char* ucKey, unsigned int n, const SBlock& roChain = SBlock(0UL,0UL));
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//Resetting the chaining block
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void ResetChain() { m_oChain = m_oChain0; }
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// Encrypt/Decrypt Buffer in Place
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void Encrypt(unsigned char* buf, unsigned int n, int iMode=ECB);
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void Decrypt(unsigned char* buf, unsigned int n, int iMode=ECB);
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// Encrypt/Decrypt from Input Buffer to Output Buffer
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void Encrypt(const unsigned char* in, unsigned char* out, unsigned int n, int iMode=ECB);
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void Decrypt(const unsigned char* in, unsigned char* out, unsigned int n, int iMode=ECB);
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//Private Functions
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private:
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unsigned int F(unsigned int ui);
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void Encrypt(SBlock&);
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void Decrypt(SBlock&);
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private:
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//The Initialization Vector, by default {0, 0}
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SBlock m_oChain0;
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SBlock m_oChain;
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unsigned int m_auiP[18];
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unsigned int m_auiS[4][256];
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static const unsigned int scm_auiInitP[18];
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static const unsigned int scm_auiInitS[4][256];
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};
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//Extract low order byte
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inline unsigned char Byte(unsigned int ui)
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{
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return (unsigned char)(ui & 0xff);
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}
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//Function F
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inline unsigned int BlowFish::F(unsigned int ui)
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{
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return ((m_auiS[0][Byte(ui>>24)] + m_auiS[1][Byte(ui>>16)]) ^ m_auiS[2][Byte(ui>>8)]) + m_auiS[3][Byte(ui)];
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}
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#endif //COMPILE_CRYPT_SUPPORT
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#endif //!_BLOWFISH_H_
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