这篇文章主要介绍“c语言怎么实现DES加密解密”的相关知识,小编通过实际案例向大家展示操作过程,操作方法简单快捷,实用性强,希望这篇“c语言怎么实现DES加密解密”文章能帮助大家解决问题。
c语言实现DES加密解密
#include "des.h" //移位表 static Table_size const shiftTable[NumberOfKeys] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}; //E扩展表 static Table_size const eTable[des_key_pc2_standard]={ 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 }; //P置换表 static Table_size const pTable[des_data_rl]={ 16, 7,20,21,29,12,28,17, 1,15,23,26, 5,18,31,10, 2, 8,24,14,32,27, 3, 9, 19,13,30, 6,22,11, 4,25 }; //数据初始置换表 static Table_size const ip0Table[des_standard] = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 }; //ip1表 static Table_size const ip1Table[des_standard]={ 40, 8,48,16,56,24,64,32, 39, 7,47,15,55,23,63,31, 38, 6,46,14,54,22,62,30, 37, 5,45,13,53,21,61,29, 36, 4,44,12,52,20,60,28, 35, 3,43,11,51,19,59,27, 34, 2,42,10,50,18,58,26, 33, 1,41, 9,49,17,57,25 }; //子密钥pc1置换表 static Table_size const desSubkeyPc1[des_key_pc1_standard] = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }; //子密钥pc2置换表 static Table_size const desSubkeyPc2[des_key_pc2_standard]={ 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 34, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32 }; //S盒表 static Table_size const sBoxTable[8][4][16]={ //S1 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13, //S2 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9, //S3 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12, //S4 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14, //S5 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3, //S6 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 10, 15, 4, 2, 7, 12, 0, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13, //S7 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 13, 0, 11, 7, 4, 0, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12, //S8 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 }; /* * 函数功能:生成16个6字节子密钥 * 参数:<key>传入8字节密钥,<key_lenght>密钥长度必须是8字节 * 返回值:返回16*(48/8)字节大小的16个子密钥 * 注释:返回值要释放 */ subkey_size __desSubKeyGeneration(subkey_size key, data_lenght_size key_lenght) { //如果传入空或长度不为8字节则返回空 if(key==NULL || key_lenght!=8) return NULL; //申请堆内存 subkey_size subkey16 = (subkey_size)malloc(NumberOfKeys * (des_key_pc2_standard / systemBit)); //清空初始化,按照申请内存大小来清空这块堆内存 memset(subkey16, 0, NumberOfKeys * (des_key_pc2_standard / systemBit)); //创建布尔型的数组,让移位代码实现更简单 int count = 0; bool tmp = 0; bool bit_table_pc1[des_key_pc1_standard]={0}; //pc1的56位数据 bool bit_table[des_standard]={0}; //64位数据 //将数据赋值到布尔型数组里面 for(int i=0; i<des_standard; i++) bit_table[i] = BIT_JUDGE(*(key + i / systemBit), (i % systemBit)); //进行PC1转换 for(int i=0; i<des_key_pc1_standard; i++) bit_table_pc1[i] = bit_table[desSubkeyPc1[i]-1]; //进行十六次密钥生成 for(int num=0; num<NumberOfKeys; num++) { //保存移位次数 count = shiftTable[num]; //进行移位 while(count--) { //前二十八位移位 tmp = bit_table_pc1[0]; for(int i=0; i<28; i++) bit_table_pc1[i]=bit_table_pc1[i+1]; bit_table_pc1[27]=tmp; //后二十八位移位 tmp = bit_table_pc1[28]; for(int i=28; i<56; i++) bit_table_pc1[i]=bit_table_pc1[i+1]; bit_table_pc1[55]=tmp; } //进行判断写入新的数据 for(int i=0; i<des_key_pc2_standard; i++) { if(bit_table_pc1[desSubkeyPc2[i]-1]) SET_BIT_NUMBER(*(subkey16 + (num * (des_key_pc2_standard / systemBit)) + (i / systemBit)), (i % systemBit)); else RESET_BIT_NUMBER(*(subkey16 + (num * (des_key_pc2_standard / systemBit)) + (i / systemBit)), (i % systemBit)); } } //返回子密钥 return subkey16; } /* * 函数功能:进行数据加密 * 参数:<data>传入8整数倍字节数据,<data_lenght>数据长度,<key>16*(48/8)字节大小的16个子密钥,<key_lenght>必须是6*16长度 * 返回值:返回加密后的数据 * 注释:返回值要释放 */ data_size __desDataEncryption(data_size data, data_lenght_size data_lenght, subkey_size key, data_lenght_size key_lenght) { //如果传入空或长度不为8字节则返回空 if(key==NULL || key_lenght!=(NumberOfKeys*(des_key_pc2_standard/systemBit)) || data==NULL || data_lenght!=8) return NULL; //申请堆内存 data_size Data16 = (data_size)malloc(des_standard/8); //清空初始化,按照申请内存大小来清空这块堆内存 memset(Data16, 0, (des_standard/8)); //创建一个布尔型的数组,将移位操作变得简单 bool bit_table[des_standard]={0}; //64位数据 bool data64_table[des_standard]={0}; //64位数据 bool extend48_table[des_key_pc2_standard]={0}; //pc2表的48位数据 bool dataL32_table[des_data_rl]={0}; //64位数据的左32 bool dataR32_table[des_data_rl]={0}; //64位数据的右32 bool tmpL32_table[des_data_rl]={0}; //临时64位数据的左32 bool tmpR32_table[des_data_rl]={0}; //临时64位数据的右32 //将数据赋值到布尔型数组里面 for(int i=0; i<des_standard; i++) bit_table[i] = BIT_JUDGE(*(data + (i / systemBit)), (i % systemBit)); //进行初始置换 for(int i=0; i<des_standard; i++) data64_table[i] = bit_table[ip0Table[i]-1]; //将64位一分为二 for(int i=0; i<des_data_rl; i++) dataL32_table[i] = data64_table[i]; for(int i=0; i<des_data_rl; i++) dataR32_table[i] = data64_table[i+32]; // 列 行 int row=0, col=0; //进行十六次轮函数 for(int num=0; num<NumberOfKeys; num++) { //将R数组赋值给L的临时数组 for(int i=0; i<des_data_rl; i++) tmpL32_table[i] = dataR32_table[i]; //将R数组进行E扩展 for(int i=0; i<des_key_pc2_standard; i++) extend48_table[i] = dataR32_table[(eTable[i]-1)]; //将E扩展后48位和子密钥进行异或 for(int i=0; i<des_key_pc2_standard; i++) extend48_table[i] = extend48_table[i] ^ (BIT_JUDGE(*(key + (num * (des_key_pc2_standard / systemBit)) + i / systemBit), (i % systemBit))); //将48位转换成32位 for(int j=0; j<des_key_pc2_standard; j+=6) { //计算出行列 row = extend48_table[j+0]*2 + extend48_table[j+5]*1; col = extend48_table[j+1]*8 + extend48_table[j+2]*4 + extend48_table[j+3]*2 + extend48_table[j+4]*1; //进行查表,并将10进制转换为四位二进制 for(int i=0; i<4; i++) dataR32_table[((j/6)*4)+i] = BIT_JUDGE(sBoxTable[j/6][row][col], i); } //将R进行转换并存入R临时数组 for(int i=0; i<des_data_rl; i++) tmpR32_table[i] = dataR32_table[pTable[i]-1]; //在用临时数组进行异或 for(int i=0; i<des_data_rl; i++) { dataR32_table[i] = (dataL32_table[i] ^ tmpR32_table[i]); } //最后将刚才的L临时数组赋值 for(int i=0; i<des_data_rl; i++) dataL32_table[i] = tmpL32_table[i]; } //将两个32位进行拼接 for(int i=0; i<des_data_rl; i++) data64_table[i] = dataL32_table[i]; for(int i=des_data_rl; i<des_standard; i++) data64_table[i] = dataR32_table[i-32]; //进行判断写入新的数据 for(int i=0; i<des_standard; i++) { if(data64_table[ip1Table[i]-1]) SET_BIT_NUMBER(*(Data16 + (i / systemBit)), (i % systemBit)); else RESET_BIT_NUMBER(*(Data16 + (i / systemBit)), (i % systemBit)); } //返回数据 return Data16; } /* * 函数功能:进行数据解密 * 参数:<data>传入加密后数据,<data_lenght>加密后数据长度,<key>16*(48/8)字节大小的16个子密钥,<key_lenght>必须是6*16长度 * 返回值:返回解密后的数据 * 注释:返回值要释放 */ data_size __desDataDecrypt(data_size data, data_lenght_size data_lenght, subkey_size key, data_lenght_size key_lenght) { //如果传入空或长度不为8字节则返回空 if(key==NULL || key_lenght!=(NumberOfKeys*(des_key_pc2_standard/systemBit)) || data==NULL || data_lenght!=8) return NULL; //申请堆内存 data_size Data16 = (data_size)malloc(des_standard/8); //清空初始化,按照申请内存大小来清空这块堆内存 memset(Data16, 0, (des_standard/8)); //创建一堆布尔型的数组,将移位操作变得简单 bool bit_table[des_standard]={0}; //64位数据 bool data64_table[des_standard]={0}; //64位数据 bool extend48_table[des_key_pc2_standard]={0}; //pc2表48位数据 bool dataL32_table[des_data_rl]={0}; //64位数据的左32位 bool dataR32_table[des_data_rl]={0}; //64位数据的右32位 bool tmpL32_table[des_data_rl]={0}; //临时64位数据的左32位 bool tmpR32_table[des_data_rl]={0}; //临时64位数据的右32位 //将数据赋值到布尔型数组里面 for(int i=0; i<des_standard; i++) bit_table[i] = BIT_JUDGE(*(data + (i / systemBit)), (i % systemBit)); //进行初始置换 for(int i=0; i<des_standard; i++) data64_table[i] = bit_table[ip0Table[i]-1]; //将64位一分为二 for(int i=0; i<des_data_rl; i++) dataR32_table[i] = data64_table[i]; for(int i=0; i<des_data_rl; i++) dataL32_table[i] = data64_table[i+32]; // 列 行 int row=0, col=0; //进行十六次轮函数(反着来) for(int num=(NumberOfKeys-1); num>=0; num--) { //将R数组赋值给L的临时数组 for(int i=0; i<des_data_rl; i++) tmpL32_table[i] = dataR32_table[i]; //将R数组进行E扩展 for(int i=0; i<des_key_pc2_standard; i++) extend48_table[i] = dataR32_table[(eTable[i]-1)]; //将E扩展后48位和子密钥进行异或 for(int i=0; i<des_key_pc2_standard; i++) extend48_table[i] = extend48_table[i] ^ (BIT_JUDGE(*(key + (num * (des_key_pc2_standard / systemBit)) + i / systemBit), (i % systemBit))); //将48位转换成32位 for(int j=0; j<des_key_pc2_standard; j+=6) { //计算出行列 row = extend48_table[j+0]*2 + extend48_table[j+5]*1; col = extend48_table[j+1]*8 + extend48_table[j+2]*4 + extend48_table[j+3]*2 + extend48_table[j+4]*1; //进行查表,并将10进制转换为四位二进制 for(int i=0; i<4; i++) dataR32_table[((j/6)*4)+i] = BIT_JUDGE(sBoxTable[j/6][row][col], i); } //将R进行转换并存入R临时数组 for(int i=0; i<des_data_rl; i++) tmpR32_table[i] = dataR32_table[pTable[i]-1]; //在用临时数组进行异或 for(int i=0; i<des_data_rl; i++) { dataR32_table[i] = (dataL32_table[i] ^ tmpR32_table[i]); } //最后将刚才的L临时数组赋值 for(int i=0; i<des_data_rl; i++) dataL32_table[i] = tmpL32_table[i]; } //将两个32位进行拼接 for(int i=0; i<des_data_rl; i++) data64_table[i] = dataR32_table[i]; for(int i=des_data_rl; i<des_standard; i++) data64_table[i] = dataL32_table[i-32]; //进行判断写入新的数据 for(int i=0; i<des_standard; i++) { if(data64_table[ip1Table[i]-1]) SET_BIT_NUMBER(*(Data16 + (i / systemBit)), (i % systemBit)); else RESET_BIT_NUMBER(*(Data16 + (i / systemBit)), (i % systemBit)); } //返回数据 return Data16; } /* * 函数功能:将数据进行DES加密 * 参数:<data>要加密的数据,<data_lenght>要加密的数据长度,<key>进行加密的密钥,<key_lenght>密钥的长度(8字节),<fillingMode>数据补位的模式选择 * 返回值:返回一个结构体,结构体内有加密后数据和加密后数据长度 */ p_desRetStruct desEncryption(data_size data, data_lenght_size data_lenght, subkey_size key, data_lenght_size key_lenght, enumFillingMode fillingMode) { if(key_lenght != 8 || (fillingMode != NOPADDING && fillingMode != PKCS5PADDING)) { return NULL; } //申请堆内存 p_desRetStruct retData = (p_desRetStruct)malloc(sizeof(desRetStruct)); //清空这块内存 memset(retData, 0, sizeof(desRetStruct)); //计算出长度 data_lenght_size mallocLenght = ((data_lenght%8==0)?(data_lenght):(((data_lenght/8)*8)+8)); //申请堆内存 retData->data = (data_size)malloc(mallocLenght); //长度进行赋值 retData->dataLenght = mallocLenght; //清空这块内存 memset(retData->data, 0, mallocLenght); //进行赋值 memcpy(retData->data, data, data_lenght); //如果是长度是8的整数倍 if(fillingMode == PKCS5PADDING && data_lenght % 8 != 0) { for(int i=0;i<8-(data_lenght%8);i++) { unsigned char num = (8 - (data_lenght % 8)); //进行拷贝 memcpy(retData->data + data_lenght + i, &num, 1); } } //获取16个子密钥 subkey_size subkey16 = __desSubKeyGeneration(key, key_lenght); //进行循环每8字节进行加密 for(int i=0; i<mallocLenght; i+=8) { //将8字节进行加密 data_size mData = __desDataEncryption(retData->data + i, 8, subkey16, 96); //将加密后字节拷贝到返回值上 memcpy(retData->data + i, mData, 8); //释放 free(mData); } //释放16个子密钥 free(subkey16); //返回加密后的数据 return retData; } /* * 函数功能:将DES加密数据进行解密 * 参数:<data>要解密的数据,<data_lenght>要解密的数据长度(8的整数倍字节),<key>进行解密的密钥,<key_lenght>密钥的长度(8字节),<fillingMode>数据补位的模式选择 * 返回值:返回一个结构体,结构体内有解密后数据和解密后数据长度 */ p_desRetStruct desDecrypt(data_size data, data_lenght_size data_lenght, data_size key, data_lenght_size key_lenght, enumFillingMode fillingMode) { if(key_lenght != 8 || (fillingMode != NOPADDING && fillingMode != PKCS5PADDING) || data_lenght%8 != 0 || data_lenght == 0) { return NULL; } //申请堆内存 p_desRetStruct retData = (p_desRetStruct)malloc(sizeof(desRetStruct)); //清空这块内存 memset(retData, 0, sizeof(desRetStruct)); //申请堆内存 retData->data = (data_size)malloc(data_lenght); //长度进行赋值 retData->dataLenght = data_lenght; //清空这块内存 memset(retData->data, 0, data_lenght); //获取16个子密钥 subkey_size subkey16 = __desSubKeyGeneration(key, key_lenght); //进行循环每8字节进行解密 for(int i=0; i<data_lenght; i+=8) { //将8字节进行解密 data_size mData = __desDataDecrypt(data + i, 8, subkey16, 96); //将解密后字节拷贝到返回值上 memcpy(retData->data + i, mData, 8); //释放 free(mData); } //按照8-(n%8)补位方式解密 if(fillingMode == PKCS5PADDING) { //如果最后一位是0x01~0x07 if(0x01 <= *(retData->data + (data_lenght - 1)) && *(retData->data + (data_lenght - 1)) <= 0x07) { //进行8-模次循环 for(int count=1; count<=*(retData->data + (data_lenght - 1)); count++) { //判断是否和最后一字节相等 if(*(retData->data + (data_lenght - 1)) == *(retData->data + (data_lenght - count))) { retData->dataLenght--; } else { //如果有一次不相等就说明该数据没有补位 retData->dataLenght = data_lenght; //退出循环 break; } } } } //按照 补位方式解密 else if(fillingMode == NOPADDING) { //从尾部开始进行8次判断 for(int count=1; count<=8; count++) { //如果这一字节等于0就位去掉 if(0x00 == *(retData->data + (data_lenght - count))) { //将长度进行减1 retData->dataLenght--; } else { //遇到正常数据进行退出循环 break; } } } //释放16个子密钥 free(subkey16); //返回加密后的数据 return retData; } /* * 函数功能:将数据进行3DES加密 * 参数:<data>要加密的数据,<data_lenght>要加密的数据长度,<key>进行加密的密钥,<key_lenght>密钥的长度(24字节),<fillingMode>数据补位的模式选择 * 返回值:返回一个结构体,结构体内有加密后数据和加密后数据长度 */ p_desRetStruct _3desEncryption(data_size data, data_lenght_size data_lenght, subkey_size key, data_lenght_size key_lenght, enumFillingMode fillingMode) { if(key_lenght != 24 || (fillingMode != NOPADDING && fillingMode != PKCS5PADDING)) { return NULL; } //申请堆内存 p_desRetStruct retData = (p_desRetStruct)malloc(sizeof(desRetStruct)); //清空这块内存 memset(retData, 0, sizeof(desRetStruct)); //计算出长度 data_lenght_size mallocLenght = ((data_lenght%8==0)?(data_lenght):(((data_lenght/8)*8)+8)); //申请堆内存 retData->data = (data_size)malloc(mallocLenght); //长度进行赋值 retData->dataLenght = mallocLenght; //清空这块内存 memset(retData->data, 0, mallocLenght); //进行赋值 memcpy(retData->data, data, data_lenght); //如果是长度是8的整数倍 if(fillingMode == PKCS5PADDING && data_lenght % 8 != 0) { for(int i=0;i<8-(data_lenght%8);i++) { unsigned char num = (8 - (data_lenght % 8)); //进行拷贝 memcpy(retData->data + data_lenght + i, &num, 1); } } //获取16个子密钥 subkey_size subkey1 = __desSubKeyGeneration(key, 8); //获取16个子密钥 subkey_size subkey2 = __desSubKeyGeneration(key+(key_lenght/3), 8); //获取16个子密钥 subkey_size subkey3 = __desSubKeyGeneration(key+((key_lenght/3)*2), 8); //进行循环每8字节进行加密 for(int i=0; i<mallocLenght; i+=8) { //将8字节进行加密 data_size mData1 = __desDataEncryption(retData->data + i, 8, subkey1, 96); data_size mData2 = __desDataDecrypt(mData1, 8, subkey2, 96); data_size mData3 = __desDataEncryption(mData2, 8, subkey3, 96); //将加密后字节拷贝到返回值上 memcpy(retData->data + i, mData3, 8); //释放 free(mData1); free(mData2); free(mData3); } //释放子密钥 free(subkey1); free(subkey2); free(subkey3); //返回加密后的数据 return retData; } /* * 函数功能:将3DES加密数据进行解密 * 参数:<data>要解密的数据,<data_lenght>要解密的数据长度(8的整数倍字节),<key>进行解密的密钥,<key_lenght>密钥的长度(24字节),<fillingMode>数据补位的模式选择 * 返回值:返回一个结构体,结构体内有解密后数据和解密后数据长度 */ p_desRetStruct _3desDecrypt(data_size data, data_lenght_size data_len