Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
1 parent
b242cf4
commit b89f955
Showing
1 changed file
with
119 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,119 @@ | ||
#include <stdint.h> | ||
#include <math.h> | ||
#include <stdlib.h> | ||
#include <stdio.h> | ||
#include <assert.h> | ||
#include <string.h> | ||
#define printf(...) (void)0; | ||
|
||
int shift[] = {7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, | ||
5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, | ||
4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, | ||
6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21}; | ||
|
||
uint32_t F(uint32_t B, uint32_t C, uint32_t D) | ||
{ | ||
return (B & C) | (~B & D); | ||
} | ||
|
||
uint32_t G(uint32_t B, uint32_t C, uint32_t D) | ||
{ | ||
return (B & D) | (C & ~D); | ||
} | ||
|
||
uint32_t H(uint32_t B, uint32_t C, uint32_t D) | ||
{ | ||
return B ^ C ^ D; | ||
} | ||
|
||
uint32_t I(uint32_t B, uint32_t C, uint32_t D) | ||
{ | ||
return C ^ (B | ~D); | ||
} | ||
|
||
|
||
uint32_t rol(uint32_t input, int count) | ||
{ | ||
return ((input << count) & 0xffffffff) | (input & 0xffffffff) >> (32-count); | ||
} | ||
|
||
void swap(uint32_t* a, uint32_t* b) | ||
{ | ||
printf("%08x <-> %08x\n", *a, *b); | ||
uint32_t c = *a; | ||
*a = *b; | ||
*b = c; | ||
} | ||
|
||
void modified_md5(unsigned char* originalblockIn, unsigned char* keyIn, unsigned char* keyOut) | ||
{ | ||
unsigned char blockIn[64]; | ||
uint32_t* block_words = (uint32_t*)blockIn; | ||
uint32_t* key_words = (uint32_t*)keyIn; | ||
uint32_t* out_words = (uint32_t*)keyOut; | ||
uint32_t A, B, C, D, Z, tmp; | ||
int i; | ||
|
||
memcpy(blockIn, originalblockIn, 64); | ||
|
||
// Each cycle does something like this: | ||
A = key_words[0]; | ||
B = key_words[1]; | ||
C = key_words[2]; | ||
D = key_words[3]; | ||
for (i = 0; i < 64; i++) | ||
{ | ||
uint32_t input; | ||
int j; | ||
if (i < 16) | ||
j = i; | ||
else if (i < 32) | ||
j = (5*i + 1) % 16; | ||
else if (i < 48) | ||
j = (3*i + 5) % 16; | ||
else if (i < 64) | ||
j = 7*i % 16; | ||
|
||
input = blockIn[4*j] << 24 | blockIn[4*j+1] << 16 | blockIn[4*j+2] << 8 | blockIn[4*j+3]; | ||
printf("Key = %08x\n", A); | ||
Z = A + input + (int)(long long)((1LL << 32) * fabs(sin(i + 1))); | ||
if (i < 16) | ||
Z = rol(Z + F(B,C,D), shift[i]); | ||
else if (i < 32) | ||
Z = rol(Z + G(B,C,D), shift[i]); | ||
else if (i < 48) | ||
Z = rol(Z + H(B,C,D), shift[i]); | ||
else if (i < 64) | ||
Z = rol(Z + I(B,C,D), shift[i]); | ||
if (i == 63) | ||
printf("Ror is %08x\n", Z); | ||
printf("Output of round %d: %08X + %08X = %08X (shift %d, constant %08X)\n", i, Z, B, Z+B, shift[i], (int)(long long)((1LL << 32) * fabs(sin(i + 1)))); | ||
Z = Z + B; | ||
tmp = D; | ||
D = C; | ||
C = B; | ||
B = Z; | ||
A = tmp; | ||
if (i == 31) | ||
{ | ||
// swapsies | ||
swap(&block_words[A & 15], &block_words[B & 15]); | ||
swap(&block_words[C & 15], &block_words[D & 15]); | ||
swap(&block_words[(A & (15<<4))>>4], &block_words[(B & (15<<4))>>4]); | ||
swap(&block_words[(A & (15<<8))>>8], &block_words[(B & (15<<8))>>8]); | ||
swap(&block_words[(A & (15<<12))>>12], &block_words[(B & (15<<12))>>12]); | ||
} | ||
} | ||
printf("%08X %08X %08X %08X\n", A, B, C, D); | ||
// Now we can actually compute the output | ||
printf("Out:\n"); | ||
printf("%08x + %08x = %08x\n", key_words[0], A, key_words[0] + A); | ||
printf("%08x + %08x = %08x\n", key_words[1], B, key_words[1] + B); | ||
printf("%08x + %08x = %08x\n", key_words[2], C, key_words[2] + C); | ||
printf("%08x + %08x = %08x\n", key_words[3], D, key_words[3] + D); | ||
out_words[0] = key_words[0] + A; | ||
out_words[1] = key_words[1] + B; | ||
out_words[2] = key_words[2] + C; | ||
out_words[3] = key_words[3] + D; | ||
|
||
} |