sha1算法的C源码实现

/* sha1.c */ /* 以下所用各种参量名称皆为sha-1在出版物上所用之公用名称 */ #include "sha1.h" /* * 以下是为 SHA1 向左环形移位宏 之定义 */ #define SHA1CircularShift(bits,word) \ (((word) << (bits)) | ((word) >> (32-(bits)))) /* 局部函数原型 */ void SHA1PadMessage(SHA1Context *); /* 定义填充信息指针 */ void SHA1ProcessMessageBlock(SHA1Context *); /* * SHA1Reset * * 以下为数据初始化之操作 * Parameters:（参数设置） * context: [in/out] * The context to reset. * */ int SHA1Reset(SHA1Context *context) { if (!context) { return shaNull; } context->Length_Low = 0; context->Length_High = 0; context->Message_Block_Index = 0; context->Intermediate_Hash[0] = 0x67452301; context->Intermediate_Hash[1] = 0xEFCDAB89; context->Intermediate_Hash[2] = 0x98BADCFE; context->Intermediate_Hash[3] = 0x10325476; context->Intermediate_Hash[4] = 0xC3D2E1F0; context->Computed = 0; context->Corrupted = 0; return shaSuccess; } /* * SHA1Result * * 以下为sha-1结果描述： *: * 该算法将会返回一个160比特的消息摘要队列 * * 或者输出计算错误 * */ int SHA1Result( SHA1Context *context, uint8_t Message_Digest[SHA1HashSize]) { int i; if (!context || !Message_Digest) { return shaNull; } if (context->Corrupted) { return context->Corrupted; } if (!context->Computed) { SHA1PadMessage(context); for(i=0; i<64; ++i) { /* 消息清零 */ context->Message_Block[i] = 0; } context->Length_Low = 0; /* 长度清零 */ context->Length_High = 0; context->Computed = 1; } for(i = 0; i < SHA1HashSize; ++i) { Message_Digest[i] = context->Intermediate_Hash[i>>2] >> 8 * ( 3 - ( i & 0x03 ) ); } return shaSuccess; } /* * 以下为sha-1输入描述： * * 接收单位长度为8字节倍数的消息 * */ int SHA1Input( SHA1Context *context, const uint8_t *message_array, unsigned length) { if (!length) { return shaSuccess; } if (!context || !message_array) { return shaNull; } if (context->Computed) { context->Corrupted = shaStateError; return shaStateError; } if (context->Corrupted) { return context->Corrupted; } while(length-- && !context->Corrupted) { context->Message_Block[context->Message_Block_Index++] = (*message_array & 0xFF); context->Length_Low += 8; if (context->Length_Low == 0) { context->Length_High++; if (context->Length_High == 0) { /* Message is too long */ context->Corrupted = 1; } } if (context->Message_Block_Index == 64) { SHA1ProcessMessageBlock(context); } message_array++; } return shaSuccess; } /* * 以下为sha-1消息块描述： * * 消息块长度为固定之512比特 * */ void SHA1ProcessMessageBlock(SHA1Context *context) { const uint32_t K[] = { /* Constants defined in SHA-1 */ 0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6 }; int t; /* 循环计数 */ uint32_t temp; /* 临时缓存 */ uint32_t W[80]; /* 字顺序 */ uint32_t A, B, C, D, E; /* 设置系统磁盘缓存块 */ /* * 以下为初始化在W队列中的头16字数据 */ for(t = 0; t < 16; t++) { W[t] = context->Message_Block[t * 4] << 24; W[t] |= context->Message_Block[t * 4 + 1] << 16; W[t] |= context->Message_Block[t * 4 + 2] << 8; W[t] |= context->Message_Block[t * 4 + 3]; } for(t = 16; t < 80; t++) { W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]); } A = context->Intermediate_Hash[0]; B = context->Intermediate_Hash[1]; C = context->Intermediate_Hash[2]; D = context->Intermediate_Hash[3]; E = context->Intermediate_Hash[4]; /* * 以下为定义算法所用之数学函数及其迭代算法描述 */ for(t = 0; t < 20; t++) { temp = SHA1CircularShift(5,A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0]; E = D; D = C; C = SHA1CircularShift(30,B); B = A; A = temp; } for(t = 20; t < 40; t++) { temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1]; E = D; D = C; C = SHA1CircularShift(30,B); B = A; A = temp; } for(t = 40; t < 60; t++) { temp = SHA1CircularShift(5,A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; E = D; D = C; C = SHA1CircularShift(30,B); B = A; A = temp; } for(t = 60; t < 80; t++) { temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3]; E = D; D = C; C = SHA1CircularShift(30,B); B = A; A = temp; } /* * 以下为迭代算法第80步（最后一步）描述 */ context->Intermediate_Hash[0] += A; context->Intermediate_Hash[1] += B; context->Intermediate_Hash[2] += C; context->Intermediate_Hash[3] += D; context->Intermediate_Hash[4] += E; context->Message_Block_Index = 0; } /* * SHA1PadMessage * 数据填充模块 */ void SHA1PadMessage(SHA1Context *context) { if (context->Message_Block_Index > 55) { context->Message_Block[context->Message_Block_Index++] = 0x80; while(context->Message_Block_Index < 64) { context->Message_Block[context->Message_Block_Index++] = 0; } SHA1ProcessMessageBlock(context); while(context->Message_Block_Index < 56) { context->Message_Block[context->Message_Block_Index++] = 0; } } else { context->Message_Block[context->Message_Block_Index++] = 0x80; while(context->Message_Block_Index < 56) { context->Message_Block[context->Message_Block_Index++] = 0; } } /* * 把最后64位保存为数据长度 */ context->Message_Block[56] = context->Length_High >> 24; context->Message_Block[57] = context->Length_High >> 16; context->Message_Block[58] = context->Length_High >> 8; context->Message_Block[59] = context->Length_High; context->Message_Block[60] = context->Length_Low >> 24; context->Message_Block[61] = context->Length_Low >> 16; context->Message_Block[62] = context->Length_Low >> 8; context->Message_Block[63] = context->Length_Low; SHA1ProcessMessageBlock(context); }