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| #include <stdio.h>
#include <string.h>
unsigned int SK[32] = {
0xE8DB227C, 0x012451B9, 0xED08A9DB, 0xC91F65C3,
0xB3D1E981, 0x319B4734, 0xA4BA5551, 0xD0F2ED2D,
0x4A00D692, 0xE0AEFE30, 0x6BBCDB4A, 0xC315F6F1,
0xB4E1B030, 0x694C4ACE, 0x479208D3, 0x3F8C7B97,
0x747777A6, 0xEDEC9BBB, 0xC8E506C1, 0xB955A92A,
0xB388FDBB, 0x1A4697C3, 0xB10826AA, 0xBB1F2207,
0x291DCD60, 0x2BA3E3A7, 0x1B83DFDD, 0x014D4FD5,
0x80C659F3, 0x3EB45B23, 0x43E36266, 0xBD22532C
};
#define GET_ULONG(n, b, i) \
(n) = ( (unsigned long) (b)[(i + 3)] << 24 ) \
| ( (unsigned long) (b)[(i + 2)] << 16 ) \
| ( (unsigned long) (b)[(i + 1)] << 8 ) \
| ( (unsigned long) (b)[(i )] ); \
#define PUT_ULONG(n, b, i) \
{ \
(b)[(i) + 3] = (unsigned char) ( (n) >> 24 ); \
(b)[(i) + 2] = (unsigned char) ( (n) >> 16 ); \
(b)[(i) + 1] = (unsigned char) ( (n) >> 8 ); \
(b)[(i) ] = (unsigned char) ( (n) ); \
}
#define SHL(x, n) ( ((x) & 0xFFFFFFFF) << n )
#define ROTL(x, n) ( SHL((x), n) | ((x) >> (32 - n)) )
#define SWAP(a, b) { unsigned t = a; a = b; b = t; t = 0; }
void SM4_Decrypt(unsigned char * input, unsigned char * output, int len);
void Round(unsigned char input[16], unsigned char output[16]);
int main(void)
{
unsigned char input[] =
{
0x7D, 0x54, 0xCB, 0xC0, 0x74, 0xDB, 0xF5, 0xD7, 0x6F, 0xD9,
0x92, 0x1B, 0xEB, 0x28, 0x46, 0x20, 0xE5, 0xD5, 0xD3, 0x60,
0x80, 0x6D, 0x36, 0x2F, 0xB0, 0x63, 0x2F, 0x61, 0x20, 0x0F,
0xA9, 0x30
};
unsigned char output[32] = { 0 };
int i;
SM4_Decrypt(input, output, 32);
for ( i = 0; i < 32; i++ )
{
printf("%c", output[i]);
}
return 0;
}
void SM4_Decrypt(unsigned char * input, unsigned char * output, int len)
{
int i;
for ( i = 0; i < 16; i++ )
SWAP(SK[i], SK[31 - i]);
while ( len > 0 )
{
Round(input, output);
input += 16;
output += 16;
len -= 16;
}
}
void Round(unsigned char input[16], unsigned char output[16])
{
unsigned long tmp[4] = { 0 };
int i;
unsigned int t = 0;
GET_ULONG(tmp[0], input, 0);
GET_ULONG(tmp[1], input, 4);
GET_ULONG(tmp[2], input, 8);
GET_ULONG(tmp[3], input, 12);
for ( i = 0; i < 32; i++ )
{
t = SK[i] ^ tmp[(i + 1) % 4] ^ tmp[(i + 2) % 4] ^ tmp[(i + 3) % 4];
tmp[i % 4] ^= t ^ ROTL(t, 2) ^ ROTL(t, 24) ^ ROTL(t, 10) ^ ROTL(t, 18);
}
for ( i = 0 ; i < 4; i++ )
GET_ULONG(SK[26 - i], input, i * 4);
PUT_ULONG(tmp[3], output, 0);
PUT_ULONG(tmp[2], output, 4);
PUT_ULONG(tmp[1], output, 8);
PUT_ULONG(tmp[0], output, 12);
}
|
