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https://github.com/fumiama/simple-crypto.git
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优化md5
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源文雨
174
md5.c
174
md5.c
@@ -48,7 +48,75 @@ static uint32_t to_uint32(const uint8_t *bytes) {
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#endif
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}
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#ifdef WORDS_BIGENDIAN
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/* break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15 */
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#define break_chunk_into_w(trunk)\
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(for(i = 0; i < 16; i++) w[i] = to_uint32((trunk) + i*4))
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#else
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/* break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15 */
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#define break_chunk_into_w(trunk) (w = (uint32_t*)(trunk))
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#endif
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//for each 512-bit chunk of message:
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#define sum(trunk) {\
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/* break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15 */\
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break_chunk_into_w(trunk);\
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\
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/* Initialize hash value for this chunk: */\
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a = h0;\
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b = h1;\
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c = h2;\
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d = h3;\
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\
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/* Main loop: */\
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for(i = 0; i < 16; i++) {\
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f = (b & c) | ((~b) & d);\
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g = i;\
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temp = d;\
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d = c;\
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c = b;\
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);\
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a = temp;\
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}\
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for(i = 16; i < 32; i++) {\
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f = (d & b) | ((~d) & c);\
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g = (5*i + 1) % 16;\
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temp = d;\
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d = c;\
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c = b;\
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);\
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a = temp;\
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}\
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for(i = 32; i < 48; i++) {\
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f = b ^ c ^ d;\
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g = (3*i + 5) % 16;\
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temp = d;\
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d = c;\
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c = b;\
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);\
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a = temp;\
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}\
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for(i = 48; i < 64; i++) {\
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f = c ^ (b | (~d));\
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g = (7*i) % 16;\
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temp = d;\
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d = c;\
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c = b;\
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);\
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a = temp;\
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}\
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\
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/* Add this chunk's hash to result so far: */\
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h0 += a;\
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h1 += b;\
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h2 += c;\
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h3 += d;\
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}
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uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
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// buffer of last trunk
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uint8_t trunk[64];
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#ifdef WORDS_BIGENDIAN
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uint32_t w[16];
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#else
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@@ -62,95 +130,41 @@ uint8_t* md5(const uint8_t *data, size_t data_len, uint8_t digest[16]) {
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uint32_t h2 = 0x98badcfe;
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uint32_t h3 = 0x10325476;
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// Message (to prepare)
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uint8_t *msg = NULL;
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size_t new_len, offset;
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size_t offset = 0;
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uint32_t a, b, c, d, i, f, g, temp;
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//Pre-processing:
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// Process the message in successive 512-bit chunks:
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if(data_len >= 64)
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for(offset=0; offset<data_len&(~0x3f); offset += 64)
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sum(data+offset);
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// Process the last trunk of message:
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//append "1" bit to message
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//append "0" bits until message length in bits ≡ 448 (mod 512)
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//append length mod (2^64) to message
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i = data_len-offset;
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if(i) memcpy(trunk, data+offset, i);
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trunk[i++] = 0x80; // append the "1" bit; most significant bit is "first"
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temp = 64-i;
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if(temp) memset(&trunk[i], 0, temp); // append "0" bits
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for (new_len = data_len + 1; new_len % (512/8) != 448/8; new_len++);
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msg = (uint8_t*)malloc(new_len + 8);
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memcpy(msg, data, data_len);
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msg[data_len] = 0x80; // append the "1" bit; most significant bit is "first"
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memset(&msg[data_len+1], 0, new_len-data_len-1); // append "0" bits
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// append the len in bits at the end of the buffer.
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to_bytes(data_len*8, msg + new_len);
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// initial_len>>29 == initial_len*8>>32, but avoids overflow.
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to_bytes(data_len>>29, msg + new_len + 4);
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// Process the message in successive 512-bit chunks:
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//for each 512-bit chunk of message:
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for(offset=0; offset<new_len; offset += (512/8)) {
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// break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15
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#ifdef WORDS_BIGENDIAN
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for (i = 0; i < 16; i++)
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w[i] = to_uint32(msg + offset + i*4);
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#else
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w = (uint32_t*)(msg + offset);
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#endif
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// Initialize hash value for this chunk:
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a = h0;
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b = h1;
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c = h2;
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d = h3;
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// Main loop:
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for(i = 0; i < 16; i++) {
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f = (b & c) | ((~b) & d);
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g = i;
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temp = d;
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d = c;
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c = b;
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
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a = temp;
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}
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for(i = 16; i < 32; i++) {
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f = (d & b) | ((~d) & c);
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g = (5*i + 1) % 16;
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temp = d;
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d = c;
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c = b;
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
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a = temp;
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}
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for(i = 32; i < 48; i++) {
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f = b ^ c ^ d;
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g = (3*i + 5) % 16;
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temp = d;
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d = c;
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c = b;
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
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a = temp;
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}
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for(i = 48; i < 64; i++) {
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f = c ^ (b | (~d));
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g = (7*i) % 16;
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temp = d;
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d = c;
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c = b;
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b += LEFTROTATE((a + f + k[i] + w[g]), r[i]);
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a = temp;
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}
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// Add this chunk's hash to result so far:
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h0 += a;
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h1 += b;
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h2 += c;
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h3 += d;
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//no enough space to fill the len in bits
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//we need to process one more trunk
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if(i > 56) {
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sum(trunk);
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memset(trunk, 0, 64);
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}
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// cleanup
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free(msg);
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// append the len in bits at the end of the buffer.
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to_bytes(data_len * 8, &trunk[56]);
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// initial_len>>29 == initial_len*8>>32, but avoids overflow.
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to_bytes(data_len>>29, &trunk[60]);
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//var char digest[16] := h0 append h1 append h2 append h3 //(Output is in little-endian)
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//sum the last trunk
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sum(trunk);
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//var char digest[16] := h0 append h1 append h2 append h3
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//(Output is in little-endian)
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to_bytes(h0, &digest[0]);
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to_bytes(h1, &digest[4]);
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to_bytes(h2, &digest[8]);
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