国密SM4对称算法实现说明（原SMS4无线局域网算法标准）
SM4分组密码算法，原名SMS4，国家密码管理局于2012年3月21日发布：http://www.oscca.gov.cn/News/201204/News_1228.htm ，但不能下载标准文档。
SM4为对称算法，密钥长度和分组长度均为128位。按原SMS4的标准描述：加密算法与密钥扩展算法都采用32轮非线性迭代结构。解密算法与加密算法的结构相同，只是轮密钥的使用顺序相反，解密轮密钥是加密轮密钥的逆序。
该算法网上的C语言实现如下：
sm4.h
1 /** 2 * file sm4.h 3 */ 4 #ifndef XYSSL_SM4_H 5 #define XYSSL_SM4_H 6 7 #define SM4_ENCRYPT 1 8 #define SM4_DECRYPT 0 9 10 /** 11 * rief SM4 context structure 12 */ 13 typedef struct 14 { 15 int mode; /*!< encrypt/decrypt */ 16 unsigned long sk[32]; /*!< SM4 subkeys */ 17 } 18 sm4_context; 19 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 /** 26 * rief SM4 key schedule (128-bit, encryption) 27 * 28 * param ctx SM4 context to be initialized 29 * param key 16-byte secret key 30 */ 31 void sm4_setkey_enc(sm4_context *ctx, unsigned char key[16]); 32 33 /** 34 * rief SM4 key schedule (128-bit, decryption) 35 * 36 * param ctx SM4 context to be initialized 37 * param key 16-byte secret key 38 */ 39 void sm4_setkey_dec(sm4_context *ctx, unsigned char key[16]); 40 41 /** 42 * rief SM4-ECB block encryption/decryption 43 * param ctx SM4 context 44 * param mode SM4_ENCRYPT or SM4_DECRYPT 45 * param length length of the input data 46 * param input input block 47 * param output output block 48 */ 49 void sm4_crypt_ecb(sm4_context *ctx, 50 int mode, 51 int length, 52 unsigned char *input, 53 unsigned char *output); 54 55 /** 56 * rief SM4-CBC buffer encryption/decryption 57 * param ctx SM4 context 58 * param mode SM4_ENCRYPT or SM4_DECRYPT 59 * param length length of the input data 60 * param iv initialization vector (updated after use) 61 * param input buffer holding the input data 62 * param output buffer holding the output data 63 */ 64 void sm4_crypt_cbc(sm4_context *ctx, 65 int mode, 66 int length, 67 unsigned char iv[16], 68 unsigned char *input, 69 unsigned char *output); 70 71 #ifdef __cplusplus 72 } 73 #endif 74 75 #endif /* sm4.h */
sm4.c
1 #include "sm4.h" 2 #include <string.h> 3 #include <stdio.h> 4 5 /* 6 * 32-bit integer manipulation macros (big endian) 7 */ 8 #ifndef GET_ULONG_BE 9 #define GET_ULONG_BE(n,b,i) 10 { 11 (n) = ((unsigned long)(b)[(i)] << 24) 12 | ((unsigned long)(b)[(i)+1] << 16) 13 | ((unsigned long)(b)[(i)+2] << 8) 14 | ((unsigned long)(b)[(i)+3]); 15 } 16 #endif 17 18 #ifndef PUT_ULONG_BE 19 #define PUT_ULONG_BE(n,b,i) 20 { 21 (b)[(i)] = (unsigned char)((n) >> 24); 22 (b)[(i)+1] = (unsigned char)((n) >> 16); 23 (b)[(i)+2] = (unsigned char)((n) >> 8); 24 (b)[(i)+3] = (unsigned char)((n)); 25 } 26 #endif 27 28 /* 29 *rotate shift left marco definition 30 * 31 */ 32 #define SHL(x,n) (((x) & 0xFFFFFFFF) << n) 33 #define ROTL(x,n) (SHL((x),n) | ((x) >> (32 - n))) 34 35 #define SWAP(a,b) { unsigned long t = a; a = b; b = t; t = 0; } 36 37 /* 38 * Expanded SM4 S-boxes 39 /* Sbox table: 8bits input convert to 8 bits output*/ 40 41 static const unsigned char SboxTable[16][16] = 42 { 43 { 0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05 }, 44 { 0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99 }, 45 { 0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62 }, 46 { 0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6 }, 47 { 0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8 }, 48 { 0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35 }, 49 { 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87 }, 50 { 0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e }, 51 { 0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1 }, 52 { 0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3 }, 53 { 0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f }, 54 { 0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51 }, 55 { 0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8 }, 56 { 0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0 }, 57 { 0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84 }, 58 { 0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48 } 59 }; 60 61 /* System parameter */ 62 static const unsigned long FK[4] = { 0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc }; 63 64 /* fixed parameter */ 65 static const unsigned long CK[32] = 66 { 67 0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269, 68 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9, 69 0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249, 70 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9, 71 0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229, 72 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299, 73 0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209, 74 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279 75 }; 76 77 78 /* 79 * private function: 80 * look up in SboxTable and get the related value. 81 * args: [in] inch: 0x00~0xFF (8 bits unsigned value). 82 */ 83 static unsigned char sm4Sbox(unsigned char inch) 84 { 85 unsigned char *pTable = (unsigned char *)SboxTable; 86 unsigned char retVal = (unsigned char)(pTable[inch]); 87 return retVal; 88 } 89 90 /* 91 * private F(Lt) function: 92 * "T algorithm" == "L algorithm" + "t algorithm". 93 * args: [in] a: a is a 32 bits unsigned value; 94 * return: c: c is calculated with line algorithm "L" and nonline algorithm "t" 95 */ 96 static unsigned long sm4Lt(unsigned long ka) 97 { 98 unsigned long bb = 0; 99 unsigned long c = 0; 100 unsigned char a[4]; 101 unsigned char b[4]; 102 PUT_ULONG_BE(ka, a, 0) 103 b[0] = sm4Sbox(a[0]); 104 b[1] = sm4Sbox(a[1]); 105 b[2] = sm4Sbox(a[2]); 106 b[3] = sm4Sbox(a[3]); 107 GET_ULONG_BE(bb, b, 0) 108 c = bb ^ (ROTL(bb, 2)) ^ (ROTL(bb, 10)) ^ (ROTL(bb, 18)) ^ (ROTL(bb, 24)); 109 return c; 110 } 111 112 /* 113 * private F function: 114 * Calculating and getting encryption/decryption contents. 115 * args: [in] x0: original contents; 116 * args: [in] x1: original contents; 117 * args: [in] x2: original contents; 118 * args: [in] x3: original contents; 119 * args: [in] rk: encryption/decryption key; 120 * return the contents of encryption/decryption contents. 121 */ 122 static unsigned long sm4F(unsigned long x0, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long rk) 123 { 124 return (x0^sm4Lt(x1^x2^x3^rk)); 125 } 126 127 128 /* private function: 129 * Calculating round encryption key. 130 * args: [in] a: a is a 32 bits unsigned value; 131 * return: sk[i]: i{0,1,2,3,...31}. 132 */ 133 static unsigned long sm4CalciRK(unsigned long ka) 134 { 135 unsigned long bb = 0; 136 unsigned long rk = 0; 137 unsigned char a[4]; 138 unsigned char b[4]; 139 PUT_ULONG_BE(ka, a, 0) 140 b[0] = sm4Sbox(a[0]); 141 b[1] = sm4Sbox(a[1]); 142 b[2] = sm4Sbox(a[2]); 143 b[3] = sm4Sbox(a[3]); 144 GET_ULONG_BE(bb, b, 0) 145 rk = bb ^ (ROTL(bb, 13)) ^ (ROTL(bb, 23)); 146 return rk; 147 } 148 149 static void sm4_setkey(unsigned long SK[32], unsigned char key[16]) 150 { 151 unsigned long MK[4]; 152 unsigned long k[36]; 153 unsigned long i = 0; 154 155 GET_ULONG_BE(MK[0], key, 0); 156 GET_ULONG_BE(MK[1], key, 4); 157 GET_ULONG_BE(MK[2], key, 8); 158 GET_ULONG_BE(MK[3], key, 12); 159 k[0] = MK[0] ^ FK[0]; 160 k[1] = MK[1] ^ FK[1]; 161 k[2] = MK[2] ^ FK[2]; 162 k[3] = MK[3] ^ FK[3]; 163 for (; i<32; i++) 164 { 165 k[i + 4] = k[i] ^ (sm4CalciRK(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i])); 166 SK[i] = k[i + 4]; 167 } 168 169 } 170 171 /* 172 * SM4 standard one round processing 173 * 174 */ 175 static void sm4_one_round(unsigned long sk[32], 176 unsigned char input[16], 177 unsigned char output[16]) 178 { 179 unsigned long i = 0; 180 unsigned long ulbuf[36]; 181 182 memset(ulbuf, 0, sizeof(ulbuf)); 183 GET_ULONG_BE(ulbuf[0], input, 0) 184 GET_ULONG_BE(ulbuf[1], input, 4) 185 GET_ULONG_BE(ulbuf[2], input, 8) 186 GET_ULONG_BE(ulbuf[3], input, 12) 187 while (i<32) 188 { 189 ulbuf[i + 4] = sm4F(ulbuf[i], ulbuf[i + 1], ulbuf[i + 2], ulbuf[i + 3], sk[i]); 190 // #ifdef _DEBUG 191 // printf("rk(%02d) = 0x%08x, X(%02d) = 0x%08x ",i,sk[i], i, ulbuf[i+4] ); 192 // #endif 193 i++; 194 } 195 PUT_ULONG_BE(ulbuf[35], output, 0); 196 PUT_ULONG_BE(ulbuf[34], output, 4); 197 PUT_ULONG_BE(ulbuf[33], output, 8); 198 PUT_ULONG_BE(ulbuf[32], output, 12); 199 } 200 201 /* 202 * SM4 key schedule (128-bit, encryption) 203 */ 204 void sm4_setkey_enc(sm4_context *ctx, unsigned char key[16]) 205 { 206 ctx->mode = SM4_ENCRYPT; 207 sm4_setkey(ctx->sk, key); 208 } 209 210 /* 211 * SM4 key schedule (128-bit, decryption) 212 */ 213 void sm4_setkey_dec(sm4_context *ctx, unsigned char key[16]) 214 { 215 int i; 216 ctx->mode = SM4_ENCRYPT; 217 sm4_setkey(ctx->sk, key); 218 for (i = 0; i < 16; i++) 219 { 220 SWAP(ctx->sk[i], ctx->sk[31 - i]); 221 } 222 } 223 224 225 /* 226 * SM4-ECB block encryption/decryption 227 */ 228 229 void sm4_crypt_ecb(sm4_context *ctx, 230 int mode, 231 int length, 232 unsigned char *input, 233 unsigned char *output) 234 { 235 while (length > 0) 236 { 237 sm4_one_round(ctx->sk, input, output); 238 input += 16; 239 output += 16; 240 length -= 16; 241 } 242 243 } 244 245 /* 246 * SM4-CBC buffer encryption/decryption 247 */ 248 void sm4_crypt_cbc(sm4_context *ctx, 249 int mode, 250 int length, 251 unsigned char iv[16], 252 unsigned char *input, 253 unsigned char *output) 254 { 255 int i; 256 unsigned char temp[16]; 257 258 if (mode == SM4_ENCRYPT) 259 { 260 while (length > 0) 261 { 262 for (i = 0; i < 16; i++) 263 output[i] = (unsigned char)(input[i] ^ iv[i]); 264 265 sm4_one_round(ctx->sk, output, output); 266 memcpy(iv, output, 16); 267 268 input += 16; 269 output += 16; 270 length -= 16; 271 } 272 } 273 else /* SM4_DECRYPT */ 274 { 275 while (length > 0) 276 { 277 memcpy(temp, input, 16); 278 sm4_one_round(ctx->sk, input, output); 279 280 for (i = 0; i < 16; i++) 281 output[i] = (unsigned char)(output[i] ^ iv[i]); 282 283 memcpy(iv, temp, 16); 284 285 input += 16; 286 output += 16; 287 length -= 16; 288 } 289 } 290 }
sm4test.c
/* * SM4/SMS4 algorithm test programme */ #include <string.h> #include <stdio.h> #include "sm4.h" int main() { unsigned char key[16] = { 0xc5, 0x01, 0xcb, 0xe8, 0xa8, 0x49, 0xb3, 0xe7, 0xf6, 0x38, 0xe7, 0xe0, 0x96, 0xe5, 0x60, 0xef }; unsigned char input[16] = { 0x87, 0xca, 0xa0, 0x4a, 0x4b, 0xa7, 0x62, 0x92, 0x50, 0xfb, 0xbe, 0x07, 0x5b, 0xd3, 0x00, 0x01 }; unsigned char output[16]; sm4_context ctx; unsigned long i; //encrypt standard testing vector //数据加密，output为加密后的数据 sm4_setkey_enc(&ctx, key); sm4_crypt_ecb(&ctx, 1, 16, input, output); for (i = 0; i<16; i++) printf("%02x ", output[i]); //输出 printf(" "); //decrypt testing //数据解密 sm4_setkey_dec(&ctx, key); sm4_crypt_ecb(&ctx, 0, 16, output, output); for (i = 0; i<16; i++) printf("%02x ", output[i]); printf(" "); return 0; }