QQTEA加密解密实现

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crypt.h

/** * The QQ2003C protocol plugin * * for gaim * * Copyright © 2004 Puzzlebird * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA * ************************************************** * Reorganized by Minmin <[e-mail]>, 2005-3-27 ************************************************** */#ifndef Crypt_H#define Crypt_H#define DECRYPT 0x00#define ENCRYPT 0x01#include "Wingdefines.h"class Crypt{public:Crypt();~Crypt();static void encrypt( unsigned char* instr, int32 instrlen, unsigned char* key,unsigned char*  outstr, int32* outstrlen_ptr);static int decrypt(unsigned char* instr, int32 instrlen, unsigned char* key,unsigned char*  outstr, int32* outstrlen_ptr);private:static int rand(void);static void teaEncipher(unsigned int *const v, const unsigned int *const k,unsigned int *const w);static void teaDecipher(unsigned int *const v, const unsigned int *const k,unsigned int *const w);static int qq_crypt ( unsigned char   flag,  unsigned char*  instr,  int32  instrlen,unsigned char*  key, unsigned char*  outstr, int32* outstrlen_ptr);};#endif

crypt.cpp

/** * The QQ2003C protocol plugin * * for gaim * * Copyright © 2004 Puzzlebird * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA * ************************************************** * Reorganized by Minmin <[e-mail]>, 2005-3-27 ************************************************** */#include "crypt.h"#include <string.h>#ifdef _WIN32#include <winsock.h>#else#include <arpa/inet.h>#endif#include <cstring>Crypt::Crypt(){}Crypt::~Crypt(){}void Crypt::teaEncipher(unsigned int *const v, const unsigned int *const k,unsigned int *const w){register unsigned inty     = ntohl(v[0]),z     = ntohl(v[1]),a     = ntohl(k[0]),b     = ntohl(k[1]),c     = ntohl(k[2]),d     = ntohl(k[3]),n     = 0x10,       /* do encrypt 16 (0x10) times */sum   = 0,delta = 0x9E3779B9; /*  0x9E3779B9 - 0x100000000 = -0x61C88647 */while (n-- > 0) {sum += delta;y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);}w[0] = htonl(y); w[1] = htonl(z);}void Crypt::teaDecipher(unsigned int *const v, const unsigned int *const k,unsigned int *const w){register unsigned inty     = ntohl(v[0]),z     = ntohl(v[1]),a     = ntohl(k[0]),b     = ntohl(k[1]),c     = ntohl(k[2]),d     = ntohl(k[3]),n     = 0x10,sum   = 0xE3779B90,/* why this ? must be related with n value*/delta = 0x9E3779B9;/* sum = delta<<5, in general sum = delta * n */while (n-- > 0) {z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);sum -= delta;}w[0] = htonl(y); w[1] = htonl(z);}void Crypt::encrypt( unsigned char* instr, int32 instrlen, unsigned char* key,unsigned char*  outstr, int32* outstrlen_ptr){unsigned charplain[8],         /* plain text buffer*/plain_pre_8[8],   /* plain text buffer, previous 8 bytes*/* crypted,        /* crypted text*/* crypted_pre_8,  /* crypted test, previous 8 bytes*/* inp;            /* current position in instr*/intpos_in_byte = 1,  /* loop in the byte */is_header=1,      /* header is one byte*/count=0,          /* number of bytes being crypted*/padding = 0;      /* number of padding stuff*///void encrypt_every_8_byte (void);/*** we encrypt every eight byte ***/#define encrypt_every_8_byte()  \{\for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {\if(is_header) { plain[pos_in_byte] ^= plain_pre_8[pos_in_byte]; }\else { plain[pos_in_byte] ^= crypted_pre_8[pos_in_byte]; }\  //待加密单元等于明文与前面已加密的8字节异或（交织算法第一步）} /* prepare plain text*/\teaEncipher( (unsigned int *) plain,\(unsigned int *) key, \(unsigned int *) crypted);   /* encrypt it*/\        //TEA加密\for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {\  crypted[pos_in_byte] ^= plain_pre_8[pos_in_byte]; \  //密文等于加密后的数据与前一单元待加密的数据异或 （交织算法第二步）} \memcpy(plain_pre_8, plain, 8);     /* prepare next*/\\crypted_pre_8   =   crypted;       /* store position of previous 8 byte*/\crypted         +=  8;             /* prepare next output*/\count           +=  8;             /* outstrlen increase by 8*/\pos_in_byte     =   0;             /* back to start*/\is_header       =   0;             /* and exit header*/\}/* encrypt_every_8_byte*/pos_in_byte = (instrlen + 0x0a) % 8; /* header padding decided by instrlen*/if (pos_in_byte) {pos_in_byte = 8 - pos_in_byte;  //求出要padding多少字节}plain[0] = (rand() & 0xf8) | pos_in_byte; //头部第一个字节memset(plain+1, rand()&0xff, pos_in_byte++); //padding n 个字节memset(plain_pre_8, 0x00, sizeof(plain_pre_8)); //前8个字节清零crypted = crypted_pre_8 = outstr;padding = 1; /* pad some stuff in header*/    //pad 2 byteswhile (padding <= 2) { /* at most two byte */if(pos_in_byte < 8) { plain[pos_in_byte++] = rand() & 0xff; padding ++; }if(pos_in_byte == 8){ encrypt_every_8_byte(); }}inp = instr;while (instrlen > 0) {if (pos_in_byte < 8) { plain[pos_in_byte++] = *(inp++); instrlen --; } //复制明文至待加密数据区if (pos_in_byte == 8){ encrypt_every_8_byte(); } //满8个字节则加密}padding = 1; /* pad some stuff in tailer*/           //pad 7 bytes 00while (padding <= 7) { /* at most sever byte*/if (pos_in_byte < 8) { plain[pos_in_byte++] = 0x00; padding ++; }if (pos_in_byte == 8){ encrypt_every_8_byte(); }}*outstrlen_ptr = count;}int Crypt::rand(void){/* it can be the real random seed function*/return 0xdead; /* override with number, convenient for debug*/}int Crypt::decrypt( unsigned char* instr, int32 instrlen, unsigned char* key,unsigned char*  outstr, int32* outstrlen_ptr){unsigned chardecrypted[8], m[8],* crypt_buff,* crypt_buff_pre_8,* outp;intcount,           //明文数据长度context_start,  //长度临时变量pos_in_byte,padding;#define decrypt_every_8_byte()  {\  bool bNeedRet = false;\for (pos_in_byte = 0; pos_in_byte < 8; pos_in_byte ++ ) {\ if (context_start + pos_in_byte >= instrlen) \{\bNeedRet = true;\break;\}\decrypted[pos_in_byte] ^= crypt_buff[pos_in_byte];\ //待解密单元等于前面已解密单元与下一个待解密单元异或}\if( !bNeedRet ) { \teaDecipher( (unsigned int *) decrypted, \(unsigned int *) key, \(unsigned int *) decrypted);\    //解密\context_start +=  8;\crypt_buff    +=  8;\pos_in_byte   =   0;\}\}/* decrypt_every_8_byte*//* at least 16 bytes and %8 == 0*/if ((instrlen % 8) || (instrlen < 16)) return 0;/* get information from header*/teaDecipher( (unsigned int *) instr,(unsigned int *) key,(unsigned int *) decrypted);   //解出头部，然后decrypted缓冲区就有初值了pos_in_byte = decrypted[0] & 0x7;count = instrlen - pos_in_byte - 10; /* this is the plaintext length*//* return if outstr buffer is not large enought or error plaintext length*/if (*outstrlen_ptr < count || count < 0) return 0;memset(m, 0, 8);crypt_buff_pre_8 = m;*outstrlen_ptr = count;   /* everything is ok! set return string length*/crypt_buff = instr + 8;   /* address of real data start */context_start = 8;        /* context is at the second 8 byte*/pos_in_byte ++;           /* start of paddng stuffv*/padding = 1;              /* at least one in header*/while (padding <= 2) {    /* there are 2 byte padding stuff in header*/if (pos_in_byte < 8) {  /* bypass the padding stuff, none sense data*/pos_in_byte ++; padding ++;}if (pos_in_byte == 8) {crypt_buff_pre_8 = instr;//if (! decrypt_every_8_byte()) return 0;decrypt_every_8_byte();}}/* while*/outp = outstr;while(count !=0) {if (pos_in_byte < 8) {*outp = crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte]; //输出明文等于前一个密文单元数据异或当前解密后单元outp ++;count --;pos_in_byte ++;}if (pos_in_byte == 8) {crypt_buff_pre_8 = crypt_buff - 8;//if (! decrypt_every_8_byte()) return 0;decrypt_every_8_byte();}}/* while*/for (padding = 1; padding < 8; padding ++) {if (pos_in_byte < 8) {if (crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte]) return 0; //若是和0异或的话则说明已解密完毕了pos_in_byte ++;}if (pos_in_byte == 8 ) {crypt_buff_pre_8 = crypt_buff;//if (! decrypt_every_8_byte()) return 0;decrypt_every_8_byte();}}/* for*/return 1;}int Crypt::qq_crypt ( unsigned char   flag,  unsigned char*  instr,  int32  instrlen,unsigned char*  key, unsigned char*  outstr, int32* outstrlen_ptr){if (flag == DECRYPT)return decrypt(instr, instrlen, key, outstr, outstrlen_ptr);elseif (flag == ENCRYPT)encrypt(instr, instrlen, key, outstr, outstrlen_ptr);return 1; /* flag must be DECRYPT or ENCRYPT*/}/* qq_crypt*/