无线局域网产品使用的SMS4密码算法简单实现

无线局域网产品使用的SMS4密码算法

 

中文文档下载地址

http://www.oscca.gov.cn/UpFile/200621016423197990.pdf

 

SMS4 Encryption Algorithm for Wireless Networks

 

英文文档下载地址

http://eprint.iacr.org/2008/329.pdf

 

对文档描述进行了简单的直译

有很多地方可以优化

仅实现了128-bit block的加解密

可根据具体应用结合CBC方式使用

 

 

/*
 * A simple implementation of SMS4 Encryption Algorithm for Wireless Networks.
 *
 * No Rights Reserved.
 */
#include <stdio.h>
#include <string.h>


#define ROTATE(a,n)     (((a) << (n)) | (((a) & 0xffffffff) >> (32 - (n))))
#define SWAP32(a)	((((a) & 0xff000000) >> 24) | (((a) & 0x000000ff) << 24) \
			| (((a) & 0x0000ff00) << 8) | (((a) & 0x00ff0000) >> 8))


static unsigned char Sbox[256] = {
	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
};

static unsigned int 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
};

static unsigned int FK[4] = {
	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
};

/*
Non-linear substitution tau
*/
static inline unsigned int
t(unsigned int A)
{
	unsigned int a0 = (A >> 24) & 0xff;
	unsigned int a1 = (A >> 16) & 0xff;
	unsigned int a2 = (A >> 8) & 0xff;
	unsigned int a3 = A & 0xff;

	unsigned int b0 = Sbox[a0];
	unsigned int b1 = Sbox[a1];
	unsigned int b2 = Sbox[a2];
	unsigned int b3 = Sbox[a3];

	unsigned int B = (((b0 << 24) & 0xff000000)
			| ((b1 << 16) & 0x00ff0000)
			| ((b2 << 8) & 0x0000ff00)
			| (b3 & 0xff));

	return B;
}

static inline unsigned int
L_ap(unsigned int B)
{
	return (B ^ (ROTATE(B, 13)) ^ (ROTATE(B, 23)));
}

static inline unsigned int
T_ap(unsigned int Z)
{
	return L_ap(t(Z));
}

/*
Key expansion

@MK	: the 128bits encryption key
@rk	: the derived round key, return value
*/
static inline void
key_exp(unsigned int MK[4], unsigned int rk[32])
{
	int i;
	unsigned int K[4];
	K[0] = MK[0] ^ FK[0];
	K[1] = MK[1] ^ FK[1];
	K[2] = MK[2] ^ FK[2];
	K[3] = MK[3] ^ FK[3];

	rk[0] = K[0] ^ T_ap(K[1] ^ K[2] ^ K[3] ^ CK[0]);
	rk[1] = K[1] ^ T_ap(K[2] ^ K[3] ^ rk[0] ^ CK[1]);
	rk[2] = K[2] ^ T_ap(K[3] ^ rk[0] ^ rk[1] ^ CK[2]);
	rk[3] = K[3] ^ T_ap(rk[0] ^ rk[1] ^ rk[2] ^ CK[3]);

	for (i = 4; i < 32; i++) {
		rk[i] = rk[i - 4] ^ T_ap(rk[i - 3] ^ rk[i - 2] ^ rk[i - 1] ^ CK[i]);
	}
}

/*
Linear substitution L
*/
static inline unsigned int
L(unsigned int B)
{
	unsigned int C;
	C = (B ^ (ROTATE(B, 2)) ^ (ROTATE(B, 10)) ^ (ROTATE(B, 18)) ^ (ROTATE(B, 24)));
	return C;
}

/*
Mixer-substitution T
*/
static inline unsigned int
T(unsigned int Z)
{
	return L(t(Z));
}

/*
reverse substitution
*/
static inline void
R(unsigned int A[4])
{
	A[0] = A[0] ^ A[3];
	A[3] = A[0] ^ A[3];
	A[0] = A[0] ^ A[3];

	A[1] = A[1] ^ A[2];
	A[2] = A[1] ^ A[2];
	A[1] = A[1] ^ A[2];
}

/*
The round function
*/
static inline unsigned int
F(unsigned int X[4], unsigned int rk)
{
	return (X[0] ^ T(X[1] ^ X[2] ^ X[3] ^ rk));
}

/*
Encryption and decryption
*/
static inline void
__sms4(unsigned int X[4], unsigned int rk[32], unsigned int Y[4], int encrypt)
{
	int i;
	unsigned int tmp[36];

	tmp[0] = X[0];
	tmp[1] = X[1];
	tmp[2] = X[2];
	tmp[3] = X[3];
	for (i = 0; i < 32; i++) {
		if (encrypt) {
			tmp[i + 4] = F(tmp + i, rk[i]);
		} else {
			tmp[i + 4] = F(tmp + i, rk[31 - i]);
		}
		//printf("rk[%2d] = %08x\t", i, rk[i]);
		//printf("X[%2d] = %08x\n", i, tmp[i + 4]);
	}
	R(tmp + 32);
	Y[0] = tmp[32];
	Y[1] = tmp[33];
	Y[2] = tmp[34];
	Y[3] = tmp[35];
}

static inline void
_sms4(unsigned int X[4], unsigned int MK[4], unsigned int Y[4], int encrypt)
{
	unsigned int rk[32];
	key_exp(MK, rk);
	__sms4(X, rk, Y, encrypt);
}

static inline void
sms4(unsigned char *plain, unsigned char *key, unsigned char *cipher, int encrypt)
{
	unsigned int *p = (unsigned int *)plain;
	unsigned int *k = (unsigned int *)key;
	unsigned int *c = (unsigned int *)cipher;
	unsigned int X[4];
	unsigned int MK[4];
	unsigned int Y[4];

	MK[0] = SWAP32(k[0]);
	MK[1] = SWAP32(k[1]);
	MK[2] = SWAP32(k[2]);
	MK[3] = SWAP32(k[3]);

	X[0] = SWAP32(p[0]);
	X[1] = SWAP32(p[1]);
	X[2] = SWAP32(p[2]);
	X[3] = SWAP32(p[3]);

	_sms4(X, MK, Y, encrypt);

	c[0] = SWAP32(Y[0]);
	c[1] = SWAP32(Y[1]);
	c[2] = SWAP32(Y[2]);
	c[3] = SWAP32(Y[3]);
}

/*
@plain	: 128-bit block
@key	: 128-bit block
@cipher	: 128-bit block
*/
void
sms4_encrypt(unsigned char *plain, unsigned char *key, unsigned char *cipher)
{
	sms4(plain, key, cipher, 1);
}

/*
@plain	: 128-bit block
@key	: 128-bit block
@cipher	: 128-bit block
*/
void
sms4_decrypt(unsigned char *cipher, unsigned char *key, unsigned char *plain)
{
	sms4(cipher, key, plain, 0);
}

void
test1(void)
{
	unsigned char plain[16] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 
					0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
	unsigned char key[16] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 
					0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
	unsigned char cipher[16] = {0x68, 0x1e, 0xdf, 0x34, 0xd2, 0x06, 0x96, 0x5e,
					0x86, 0xb3, 0xe9, 0x4f, 0x53, 0x6e, 0x42, 0x46};
	unsigned char buf[16];
	int i;

	sms4_encrypt(plain, key, buf);
	for (i = 0; i < 16; i++) {
		printf("0x%02x ", buf[i]);
	}
	printf("\n");

	if (memcmp(cipher, buf, 16)) {
		printf("1 error\n");
	}

	sms4_decrypt(cipher, key, buf);
	for (i = 0; i < 16; i++) {
		printf("0x%02x ", buf[i]);
	}
	printf("\n");

}

void
test1000000(void)
{
	unsigned char plain[16] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 
					0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
	unsigned char key[16] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 
					0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
	unsigned char cipher[16] = {0x59, 0x52, 0x98, 0xc7, 0xc6, 0xfd, 0x27, 0x1f,
					0x04, 0x02, 0xf8, 0x04, 0xc3, 0x3d, 0x3f, 0x66};

	unsigned char buf[16];
	int i;

	memcpy(buf, plain, 16);
	for (i = 0; i < 1000000; i++) {
		sms4_encrypt(buf, key, buf);
	}

	for (i = 0; i < 16; i++) {
		printf("0x%02x ", buf[i]);
	}
	printf("\n");

	if (memcmp(cipher, buf, 16)) {
		printf("1000000 error\n");
	}

	memcpy(buf, cipher, 16);
	for (i = 0; i < 1000000; i++) {
		sms4_decrypt(buf, key, buf);
	}

	for (i = 0; i < 16; i++) {
		printf("0x%02x ", buf[i]);
	}
	printf("\n");

}

int
main(void)
{
	test1();
	test1000000();

	return 0;
}