code_app/base/HGMd5.cpp

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2022-05-03 10:25:52 +00:00
#include "HGMd5.h"
#include "HGInc.h"
/* Constants for MD5Transform routine. */
/* md5转换用到的常量算法本身规定的 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21
/*
md5算法规定的md5加密都要做的运算
md5
F, G, H and I are basic MD5 functions.
*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))
/*
ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
/*
FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) { (a) += F ((b), (c), (d)) + (x) + (HGUInt)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
#define GG(a, b, c, d, x, s, ac) { (a) += G ((b), (c), (d)) + (x) + (HGUInt)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
#define HH(a, b, c, d, x, s, ac) { (a) += H ((b), (c), (d)) + (x) + (HGUInt)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
#define II(a, b, c, d, x, s, ac) { (a) += I ((b), (c), (d)) + (x) + (HGUInt)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
/* MD5 context. */
typedef struct
{
/* state (ABCD) */
/*四个32bits数用于存放最终计算得到的消息摘要。当消息长度〉512bits时也用于存放每个512bits的中间结果*/
HGUInt state[4];
/* number of bits, modulo 2^64 (lsb first) */
/*存储原始信息的bits数长度,不包括填充的bits最长为 2^64 bits因为2^64是一个64位数的最大值*/
HGUInt count[2];
/* input buffer */
/*存放输入的信息的缓冲区512bits*/
HGByte buffer[64];
}MD5_CTX;
/* MD5 initialization. Begins an MD5 operation, writing a new context. */
/*初始化md5的结构*/
static void MD5Init(MD5_CTX* ctx)
{
/*将当前的有效信息的长度设成0,这个很简单,还没有有效信息,长度当然是0了*/
ctx->count[0] = 0;
ctx->count[1] = 0;
/* Load magic initialization constants.*/
/*初始化链接变量,算法要求这样,这个没法解释了*/
ctx->state[0] = 0x67452301;
ctx->state[1] = 0xefcdab89;
ctx->state[2] = 0x98badcfe;
ctx->state[3] = 0x10325476;
}
/*
4copy到字符形式的缓冲区中
output
input
lenoutput缓冲区的长度4
*/
static void MD5Encode(HGByte* output, const HGUInt* input, HGUInt len)
{
for (HGUInt i = 0, j = 0; j < len; i++, j += 4)
{
output[j] = (HGByte)(input[i] & 0xFF);
output[j + 1] = (HGByte)((input[i] >> 8) & 0xFF);
output[j + 2] = (HGByte)((input[i] >> 16) & 0xFF);
output[j + 3] = (HGByte)((input[i] >> 24) & 0xFF);
}
}
/*
copy到4字节的整数中
output
input
len4
*/
static void MD5Decode(HGUInt* output, const HGByte* input, HGUInt len)
{
for (HGUInt i = 0, j = 0; j < len; i++, j += 4)
{
output[i] = ((HGUInt)input[j]) | (((HGUInt)input[j + 1]) << 8) | (((HGUInt)input[j + 2]) << 16) | (((HGUInt)input[j + 3]) << 24);
}
}
/*
512bits信息(block缓冲区)
state[4]md5结构中的state[4]512bits信息加密的中间结果或者最终结果
block[64]512bits信息
*/
static void MD5Transform(HGUInt* state, const HGByte* block)
{
HGUInt a = state[0], b = state[1], c = state[2], d = state[3], x[16];
MD5Decode(x, block, 64);
/* Round 1 */
FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
/* Round 2 */
GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
/* Round 3 */
HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */
/* Round 4 */
II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
/* Zeroize sensitive information. */
memset(x, 0, sizeof(x));
}
/*
MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.
md5结构
contextmd5结构
input
inputLeninput的长度
*/
static void MD5Update(MD5_CTX* ctx, const HGByte* data, HGUInt size)
{
HGUInt i, index, partLen;
/*
bits长度的字节数的模64, 64bytes=512bits
512bits
512bits进行一次处理
*/
index = (HGUInt)((ctx->count[0] >> 3) & 0x3F);
/* Update number of bits *//*更新已有信息的bits长度 */
if ((ctx->count[0] += ((HGUInt)size << 3)) < ((HGUInt)size << 3))
ctx->count[1]++;
ctx->count[1] += ((HGUInt)size >> 29);
/* 计算已有的字节数长度还差多少字节可以 凑成64的整倍数 */
partLen = 64 - index;
/* 如果当前输入的字节数 大于 已有字节数长度补足64字节整倍数所差的字节数 */
if (size >= partLen)
{
/* 用当前输入的内容把ctx->buffer的内容补足512bits */
memcpy(&ctx->buffer[index], data, partLen);
/* 用基本函数对填充满的512bits已经保存到ctx->buffer中 做一次转换转换结果保存到ctx->state中 */
MD5Transform(ctx->state, ctx->buffer);
/*
<data缓冲区中>512bits的话
ctx->state中
*/
for (i = partLen; i + 63 < size; i += 64) /* 把i+63<size改为i+64<=size更容易理解 */
MD5Transform(ctx->state, &data[i]);
index = 0;
}
else
{
i = 0;
}
/* 将输入缓冲区中的不足填充满512bits的剩余内容填充到ctx->buffer中留待以后再作处理 */
memcpy(&ctx->buffer[index], &data[i], size - i);
}
/*
MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context.
digest
contextmd5结构
*/
static void MD5Final(MD5_CTX* ctx, HGByte* md5)
{
/*
bits填充的缓冲区64bits数被512除其余数为448时
bits的最大值为512=64*8
*/
static const HGByte MD5_PADDING[64] =
{
0x80, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
HGByte bits[8];
HGUInt index, padLen;
/* 将要被转换的信息(所有的)的bits长度拷贝到bits中 */
MD5Encode(bits, ctx->count, 8);
/* 计算所有的bits长度的字节数的模64, 64bytes=512bits */
index = (HGUInt)((ctx->count[0] >> 3) & 0x3F);
/* 计算需要填充的字节数padLen的取值范围在1-64之间 */
padLen = (index < 56) ? (56 - index) : (120 - index);
/* 这一次函数调用绝对不会再导致MD5Transform的被调用因为这一次不会填满512bits */
MD5Update(ctx, MD5_PADDING, padLen);
/* 补上原始信息的bits长度bits长度固定的用64bits表示这一次能够恰巧凑够512bits不会多也不会少 */
MD5Update(ctx, bits, 8);
/* Store state in digest */
MD5Encode(md5, ctx->state, 16);
memset(ctx, 0, sizeof(MD5_CTX));
}
HGResult HGAPI HGBase_MakeMd5(const HGByte* data, HGUInt size, HGByte* md5)
{
if (NULL == data || 0 == size || NULL == md5)
{
return HGBASE_ERR_INVALIDARG;
}
MD5_CTX ctx;
MD5Init(&ctx);
MD5Update(&ctx, data, size);
MD5Final(&ctx, md5);
return HGBASE_ERR_OK;
}