fumiama/simple-crypto
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优化md5

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源文雨
2022-04-18 11:42:01 +08:00
parent 01e254f8e2
commit e46a95a06d
3 changed files with 50 additions and 110 deletions
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72
md5.c
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@@ -49,7 +49,11 @@ static uint32_t to_uint32(const uint8_t *bytes) {
}
uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
uint32_t w[16];
#ifdef WORDS_BIGENDIAN
uint32_t w[16];
#else
uint32_t* w;
#endif
// These vars will contain the hash
// Initialize variables - simple count in nibbles:
@@ -85,8 +89,12 @@ uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
//for each 512-bit chunk of message:
for(offset=0; offset<new_len; offset += (512/8)) {
// break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15
for (i = 0; i < 16; i++)
w[i] = to_uint32(msg + offset + i*4);
#ifdef WORDS_BIGENDIAN
for (i = 0; i < 16; i++)
w[i] = to_uint32(msg + offset + i*4);
#else
w = (uint32_t*)(msg + offset);
#endif
// Initialize hash value for this chunk:
a = h0;
@@ -95,28 +103,41 @@ uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
d = h3;
// Main loop:
for(i = 0; i<64; i++) {
if (i < 16) {
f = (b & c) | ((~b) & d);
g = i;
} else if (i < 32) {
f = (d & b) | ((~d) & c);
g = (5*i + 1) % 16;
} else if (i < 48) {
f = b ^ c ^ d;
g = (3*i + 5) % 16;
} else {
f = c ^ (b | (~d));
g = (7*i) % 16;
}
for(i = 0; i < 16; i++) {
f = (b & c) | ((~b) & d);
g = i;
temp = d;
d = c;
c = b;
b = b + LEFTROTATE((a + f + k[i] + w[g]), r[i]);
b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
a = temp;
}
for(i = 16; i < 32; i++) {
f = (d & b) | ((~d) & c);
g = (5*i + 1) % 16;
temp = d;
d = c;
c = b;
b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
a = temp;
}
for(i = 32; i < 48; i++) {
f = b ^ c ^ d;
g = (3*i + 5) % 16;
temp = d;
d = c;
c = b;
b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
a = temp;
}
for(i = 48; i < 64; i++) {
f = c ^ (b | (~d));
g = (7*i) % 16;
temp = d;
d = c;
c = b;
b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
a = temp;
}
// Add this chunk's hash to result so far:
@@ -124,7 +145,6 @@ uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
h1 += b;
h2 += c;
h3 += d;
}
// cleanup
@@ -139,11 +159,12 @@ uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
}
#ifdef TEST_SIMPLE_CRYPTO
#include <stdio.h>
int main(int argc, char **argv) {
char *msg;
size_t len;
int i;
uint8_t* result;
uint8_t result[16];
if (argc < 2) {
printf("usage: %s 'string'\n", argv[0]);
@@ -152,12 +173,11 @@ int main(int argc, char **argv) {
msg = argv[1];
len = strlen(msg);
result = md5((uint8_t*)msg, len);
md5((uint8_t*)msg, len, result);
// display result
for (i = 0; i < 16; i++)
printf("%2.2x", result[i]);
puts("");
free(result);
putchar('\n');
return 0;
}