[数据结构与算法]C语言实现SM4加解密算法

SM4加解密

#include <string.h>
#include <stdio.h>
#include <time.h>
/*--------------------------------------------------------------------------------------------------------------*/
#define SM4_ENCRYPT     1
#define SM4_DECRYPT     0
/*--------------------------------------------------------------------------------------------------------------*/
/**
* \brief          SM4 context structure
*/
typedef struct
{
	int mode;                   /*!<  encrypt/decrypt   */
	unsigned long sk[32];       /*!<  SM4 subkeys       */
}
sm4_context;
/*--------------------------------------------------------------------------------------------------------------*/
/**
* \brief          SM4 key schedule (128-bit, encryption)
*
* \param ctx      SM4 context to be initialized
* \param key      16-byte secret key
*/
void sm4_setkey_enc(sm4_context *ctx, unsigned char key[16]);
/*--------------------------------------------------------------------------------------------------------------*/
/**
* \brief          SM4 key schedule (128-bit, decryption)
*
* \param ctx      SM4 context to be initialized
* \param key      16-byte secret key
*/
void sm4_setkey_dec(sm4_context *ctx, unsigned char key[16]);
/*--------------------------------------------------------------------------------------------------------------*/
/**
* \brief          SM4-ECB block encryption/decryption
* \param ctx      SM4 context
* \param mode     SM4_ENCRYPT or SM4_DECRYPT
* \param length   length of the input data
* \param input    input block
* \param output   output block
*/
void sm4_crypt_ecb(sm4_context *ctx,
	int mode,
	int length,
	unsigned char *input,
	unsigned char *output);
/*--------------------------------------------------------------------------------------------------------------*/
/**
* \brief          SM4-CBC buffer encryption/decryption
* \param ctx      SM4 context
* \param mode     SM4_ENCRYPT or SM4_DECRYPT
* \param length   length of the input data
* \param iv       initialization vector (updated after use)
* \param input    buffer holding the input data
* \param output   buffer holding the output data
*/
void sm4_crypt_cbc(sm4_context *ctx,
	int mode,
	int length,
	unsigned char iv[16],
	unsigned char *input,
	unsigned char *output);
/*--------------------------------------------------------------------------------------------------------------*/
/*
* 32-bit integer manipulation macros (big endian)
*/
#ifndef GET_ULONG_BE
#define GET_ULONG_BE(n,b,i)                             \
{                                                       \
    (n) = ( (unsigned long) (b)[(i)    ] << 24 )        \
        | ( (unsigned long) (b)[(i) + 1] << 16 )        \
        | ( (unsigned long) (b)[(i) + 2] <<  8 )        \
        | ( (unsigned long) (b)[(i) + 3]       );       \
}
#endif
/*--------------------------------------------------------------------------------------------------------------*/
#ifndef PUT_ULONG_BE
#define PUT_ULONG_BE(n,b,i)                             \
{                                                       \
    (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
    (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
    (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
    (b)[(i) + 3] = (unsigned char) ( (n)       );       \
}
#endif
/*--------------------------------------------------------------------------------------------------------------*/
/*
*rotate shift left marco definition
*
*/
#define  SHL(x,n) (((x) & 0xFFFFFFFF) << n)
#define ROTL(x,n) (SHL((x),n) | ((x) >> (32 - n)))
#define SWAP(a,b) { unsigned long t = a; a = b; b = t; t = 0; }
/*--------------------------------------------------------------------------------------------------------------*/
/*
* Expanded SM4 S-boxes
/* Sbox table: 8bits input convert to 8 bits output*/
static const unsigned char SboxTable[16][16] =
{
	{ 0xd6,0x90,0xe9,0xfe,0xcc,0xe1,0x3d,0xb7,0x16,0xb6,0x14,0xc2,0x28,0xfb,0x2c,0x05 },
	{ 0x2b,0x67,0x9a,0x76,0x2a,0xbe,0x04,0xc3,0xaa,0x44,0x13,0x26,0x49,0x86,0x06,0x99 },
	{ 0x9c,0x42,0x50,0xf4,0x91,0xef,0x98,0x7a,0x33,0x54,0x0b,0x43,0xed,0xcf,0xac,0x62 },
	{ 0xe4,0xb3,0x1c,0xa9,0xc9,0x08,0xe8,0x95,0x80,0xdf,0x94,0xfa,0x75,0x8f,0x3f,0xa6 },
	{ 0x47,0x07,0xa7,0xfc,0xf3,0x73,0x17,0xba,0x83,0x59,0x3c,0x19,0xe6,0x85,0x4f,0xa8 },
	{ 0x68,0x6b,0x81,0xb2,0x71,0x64,0xda,0x8b,0xf8,0xeb,0x0f,0x4b,0x70,0x56,0x9d,0x35 },
	{ 0x1e,0x24,0x0e,0x5e,0x63,0x58,0xd1,0xa2,0x25,0x22,0x7c,0x3b,0x01,0x21,0x78,0x87 },
	{ 0xd4,0x00,0x46,0x57,0x9f,0xd3,0x27,0x52,0x4c,0x36,0x02,0xe7,0xa0,0xc4,0xc8,0x9e },
	{ 0xea,0xbf,0x8a,0xd2,0x40,0xc7,0x38,0xb5,0xa3,0xf7,0xf2,0xce,0xf9,0x61,0x15,0xa1 },
	{ 0xe0,0xae,0x5d,0xa4,0x9b,0x34,0x1a,0x55,0xad,0x93,0x32,0x30,0xf5,0x8c,0xb1,0xe3 },
	{ 0x1d,0xf6,0xe2,0x2e,0x82,0x66,0xca,0x60,0xc0,0x29,0x23,0xab,0x0d,0x53,0x4e,0x6f },
	{ 0xd5,0xdb,0x37,0x45,0xde,0xfd,0x8e,0x2f,0x03,0xff,0x6a,0x72,0x6d,0x6c,0x5b,0x51 },
	{ 0x8d,0x1b,0xaf,0x92,0xbb,0xdd,0xbc,0x7f,0x11,0xd9,0x5c,0x41,0x1f,0x10,0x5a,0xd8 },
	{ 0x0a,0xc1,0x31,0x88,0xa5,0xcd,0x7b,0xbd,0x2d,0x74,0xd0,0x12,0xb8,0xe5,0xb4,0xb0 },
	{ 0x89,0x69,0x97,0x4a,0x0c,0x96,0x77,0x7e,0x65,0xb9,0xf1,0x09,0xc5,0x6e,0xc6,0x84 },
	{ 0x18,0xf0,0x7d,0xec,0x3a,0xdc,0x4d,0x20,0x79,0xee,0x5f,0x3e,0xd7,0xcb,0x39,0x48 }
};
/*--------------------------------------------------------------------------------------------------------------*/
/* System parameter */
static const unsigned long FK[4] =
{ 0xa3b1bac6,0x56aa3350,0x677d9197,0xb27022dc };
/*--------------------------------------------------------------------------------------------------------------*/
/* fixed parameter */
static const unsigned long CK[32] =
{
	0x00070e15,0x1c232a31,0x383f464d,0x545b6269,
	0x70777e85,0x8c939aa1,0xa8afb6bd,0xc4cbd2d9,
	0xe0e7eef5,0xfc030a11,0x181f262d,0x343b4249,
	0x50575e65,0x6c737a81,0x888f969d,0xa4abb2b9,
	0xc0c7ced5,0xdce3eaf1,0xf8ff060d,0x141b2229,
	0x30373e45,0x4c535a61,0x686f767d,0x848b9299,
	0xa0a7aeb5,0xbcc3cad1,0xd8dfe6ed,0xf4fb0209,
	0x10171e25,0x2c333a41,0x484f565d,0x646b7279
};
/*--------------------------------------------------------------------------------------------------------------*/
/*
* private function:
* look up in SboxTable and get the related value.
* args:    [in] inch: 0x00~0xFF (8 bits unsigned value).
*/
static unsigned char sm4Sbox(unsigned char inch)
{
	unsigned char *pTable = (unsigned char *)SboxTable;
	unsigned char retVal = (unsigned char)(pTable[inch]);
	return retVal;
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* private F(Lt) function:
* "T algorithm" == "L algorithm" + "t algorithm".
* args:    [in] a: a is a 32 bits unsigned value;
* return: c: c is calculated with line algorithm "L" and nonline algorithm "t"
*/
static unsigned long sm4Lt(unsigned long ka)
{
	unsigned long bb = 0;
	unsigned long c = 0;
	unsigned char a[4];
	unsigned char b[4];
	PUT_ULONG_BE(ka, a, 0)
		b[0] = sm4Sbox(a[0]);
	b[1] = sm4Sbox(a[1]);
	b[2] = sm4Sbox(a[2]);
	b[3] = sm4Sbox(a[3]);
	GET_ULONG_BE(bb, b, 0)
		c = bb ^ (ROTL(bb, 2)) ^ (ROTL(bb, 10)) ^ (ROTL(bb, 18)) ^ (ROTL(bb, 24));
	return c;
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* private F function:
* Calculating and getting encryption/decryption contents.
* args:    [in] x0: original contents;
* args:    [in] x1: original contents;
* args:    [in] x2: original contents;
* args:    [in] x3: original contents;
* args:    [in] rk: encryption/decryption key;
* return the contents of encryption/decryption contents.
*/
static unsigned long sm4F(unsigned long x0, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long rk)
{
	return (x0^sm4Lt(x1^x2^x3^rk));
}
/*--------------------------------------------------------------------------------------------------------------*/
/* private function:
* Calculating round encryption key.
* args:    [in] a: a is a 32 bits unsigned value;
* return: sk[i]: i{0,1,2,3,...31}.
*/
static unsigned long sm4CalciRK(unsigned long ka)
{
	unsigned long bb = 0;
	unsigned long rk = 0;
	unsigned char a[4];
	unsigned char b[4];
	PUT_ULONG_BE(ka, a, 0)
		b[0] = sm4Sbox(a[0]);
	b[1] = sm4Sbox(a[1]);
	b[2] = sm4Sbox(a[2]);
	b[3] = sm4Sbox(a[3]);
	GET_ULONG_BE(bb, b, 0)
		rk = bb ^ (ROTL(bb, 13)) ^ (ROTL(bb, 23));
	return rk;
}
/*--------------------------------------------------------------------------------------------------------------*/
static void sm4_setkey(unsigned long SK[32], unsigned char key[16])
{
	unsigned long MK[4];
	unsigned long k[36];
	unsigned long i = 0;

	GET_ULONG_BE(MK[0], key, 0);
	GET_ULONG_BE(MK[1], key, 4);
	GET_ULONG_BE(MK[2], key, 8);
	GET_ULONG_BE(MK[3], key, 12);
	k[0] = MK[0] ^ FK[0];
	k[1] = MK[1] ^ FK[1];
	k[2] = MK[2] ^ FK[2];
	k[3] = MK[3] ^ FK[3];
	for (; i<32; i++)
	{
		k[i + 4] = k[i] ^ (sm4CalciRK(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i]));
		SK[i] = k[i + 4];
	}

}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* SM4 standard one round processing
*
*/
static void sm4_one_round(unsigned long sk[32],
	unsigned char input[16],
	unsigned char output[16])
{
	unsigned long i = 0;
	unsigned long ulbuf[36];

	memset(ulbuf, 0, sizeof(ulbuf));
	GET_ULONG_BE(ulbuf[0], input, 0)
		GET_ULONG_BE(ulbuf[1], input, 4)
		GET_ULONG_BE(ulbuf[2], input, 8)
		GET_ULONG_BE(ulbuf[3], input, 12)
		while (i<32)
		{
			ulbuf[i + 4] = sm4F(ulbuf[i], ulbuf[i + 1], ulbuf[i + 2], ulbuf[i + 3], sk[i]);
			i++;
		}
	PUT_ULONG_BE(ulbuf[35], output, 0);
	PUT_ULONG_BE(ulbuf[34], output, 4);
	PUT_ULONG_BE(ulbuf[33], output, 8);
	PUT_ULONG_BE(ulbuf[32], output, 12);
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* SM4 key schedule (128-bit, encryption)
*/
void sm4_setkey_enc(sm4_context *ctx, unsigned char key[16])
{
	ctx->mode = SM4_ENCRYPT;
	sm4_setkey(ctx->sk, key);
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* SM4 key schedule (128-bit, decryption)
*/
void sm4_setkey_dec(sm4_context *ctx, unsigned char key[16])
{
	int i;
	ctx->mode = SM4_ENCRYPT;
	sm4_setkey(ctx->sk, key);
	for (i = 0; i < 16; i++)
	{
		SWAP(ctx->sk[i], ctx->sk[31 - i]);
	}
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* SM4-ECB block encryption/decryption
*/
void sm4_crypt_ecb(sm4_context *ctx,
	int mode,
	int length,
	unsigned char *input,
	unsigned char *output)
{
	while (length > 0)
	{
		sm4_one_round(ctx->sk, input, output);
		input += 16;
		output += 16;
		length -= 16;
	}
}
/*--------------------------------------------------------------------------------------------------------------*/
/*
* SM4-CBC buffer encryption/decryption
*/
void sm4_crypt_cbc(sm4_context *ctx,
	int mode,
	int length,
	unsigned char iv[16],
	unsigned char *input,
	unsigned char *output)
{
	int i;
	unsigned char temp[16];

	if (mode == SM4_ENCRYPT)
	{
		while (length > 0)
		{
			for (i = 0; i < 16; i++)
				output[i] = (unsigned char)(input[i] ^ iv[i]);

			sm4_one_round(ctx->sk, output, output);
			memcpy(iv, output, 16);

			input += 16;
			output += 16;
			length -= 16;
		}
	}
	else /* SM4_DECRYPT */
	{
		while (length > 0)
		{
			memcpy(temp, input, 16);
			sm4_one_round(ctx->sk, input, output);

			for (i = 0; i < 16; i++)
				output[i] = (unsigned char)(output[i] ^ iv[i]);

			memcpy(iv, temp, 16);

			input += 16;
			output += 16;
			length -= 16;
		}
	}
}
/*--------------------------------------------------------------------------------------------------------------*/
int main()
{
	unsigned char key[16] = { 1, 35, 69, 103, 137, 171, 205, 239, 254, 220, 186, 152, 118, 84, 50, 16 };
	unsigned char input[16] = { 101, 134, 251, 182, 61, 89, 68, 67, 217, 233, 54, 168, 235, 209, 94, 31 };
	unsigned char output[16];
	sm4_context ctx;
	unsigned long i;

	sm4_setkey_dec(&ctx, key);
	sm4_crypt_ecb(&ctx, 0, 16, input, output);
	for (i = 0; i<16; i++)
		printf("%c", output[i]);
	printf("\n");
	return 0;
}