#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
#define R_memset(x, y, z) memset(x, y, z)
#define R_memcpy(x, y, z) memcpy(x, y, z)
#define R_memcmp(x, y, z) memcmp(x, y, z)
typedef unsigned long UINT4;
typedef unsigned char *POINTER;
typedef struct {
/*四個32bits數,用於存放最終計算得到的消息摘要.當消息長度>512bits時,也用於存放每個512bits的中間結果*/
UINT4 state[4];
/*存儲原始信息的bits數長度,不包括填充的bits,最長為2^64 bits*/
UINT4 count[2];
/*存放輸入的信息的緩沖區,512bits*/
unsigned char buffer[64];
} MD5_CTX;
static void MD5Transform(UINT4[4], unsigned char[64]);
static void Encode(unsigned char *, UINT4 *, unsigned int);
static void Decode(UINT4 *, unsigned char *, unsigned int);
/*
用於bits填充的緩沖區,當欲加密的信息的bits數被512除其余數為448時,需要填充的bits的最大值為512=64*8*/
static unsigned char 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
};
/*接下來的這幾個宏定義是md5算法規定的,就是對信息進行md5加密都要做的運算*/
#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)))
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
#define FF(a, b, c, d, x, s, ac) {\
(a) += F ((b), (c), (d)) + (x) + (UINT4)(ac);\
(a) = ROTATE_LEFT ((a), (s));\
(a) += (b);\
}
#define GG(a, b, c, d, x, s, ac) {\
(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac);\
(a) = ROTATE_LEFT ((a), (s));\
(a) += (b);\
}
#define HH(a, b, c, d, x, s, ac) {\
(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac);\
(a) = ROTATE_LEFT ((a), (s));\
(a) += (b);\
}
#define II(a, b, c, d, x, s, ac) {\
(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac);\
(a) = ROTATE_LEFT ((a), (s));\
(a) += (b);\
}