SMS4算法由国家商用密码管理办公室发布，其算法的介绍可以从国家商用密码管理办公室的网站上下载到：
http://www.oscca.gov.cn/Doc/6/News_1106.htm
我花了点时间，简单的实现了这个算法，代码如下：
其中有不少代码是可以进一步优化以提高速度的，比如 i%4 => i&3 ; i*8 => i << 3
#include < stdio.h > #define ROUND 32 static unsigned long FK[ 4 ] = { 0xA3B1BAC6 , 0x56AA3350 , 0x677D9197 , 0xB27022DC }; static unsigned long CK[ROUND] = { 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 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 }; #define ROL(x,y) ((x)<<(y) | (x)>>(32-(y))) unsigned long T1(unsigned long dwA){ unsigned char a0[ 4 ] = { 0 }; unsigned char b0[ 4 ] = { 0 }; unsigned long dwB = 0 ; unsigned long dwC = 0 ; int i = 0 ; for (i = 0 ;i < 4 ;i ++ ) { a0[i] = (dwA >> (i * 8 )) & 0xff ; b0[i] = Sbox[a0[i]]; dwB |= (b0[i] << (i * 8 )); } dwC = dwB ^ ROL(dwB, 2 ) ^ ROL(dwB, 10 ) ^ ROL(dwB, 18 ) ^ ROL(dwB, 24 ); return dwC;}unsigned long T2(unsigned long dwA){ unsigned char a0[ 4 ] = { 0 }; unsigned char b0[ 4 ] = { 0 }; unsigned long dwB = 0 ; unsigned long dwC = 0 ; int i = 0 ; for (i = 0 ;i < 4 ;i ++ ) { a0[i] = (dwA >> (i * 8 )) & 0xff ; b0[i] = Sbox[a0[i]]; dwB |= (b0[i] << (i * 8 )); } dwC = dwB ^ ROL(dwB, 13 ) ^ ROL(dwB, 23 ); return dwC;} /* MK[4] is the Encrypt Key, rk[32] is Round Key */ void Key_Expansion(unsigned long MK[], unsigned long rk[]){ unsigned long K[ 4 ] = { 0 }; int i = 0 ; for (i = 0 ;i < 4 ;i ++ ) { K[i] = MK[i] ^ FK[i]; } for (i = 0 ;i < ROUND;i ++ ) { K[i % 4 ] ^= T2(K[(i + 1 ) % 4 ] ^ K[(i + 2 ) % 4 ] ^ K[(i + 3 ) % 4 ] ^ CK[i]); rk[i] = K[i % 4 ]; }} /* X[4] is PlainText, rk[32] is round Key, Y[4] is CipherText */ void ECB_Encryption(unsigned long X[], unsigned long rk[], unsigned long Y[]){ unsigned long tempX[ 4 ] = { 0 }; int i = 0 ; for (i = 0 ;i < 4 ;i ++ ) { tempX[i] = X[i]; } for (i = 0 ;i < ROUND;i ++ ) { tempX[i % 4 ] ^= T1(tempX[(i + 1 ) % 4 ] ^ tempX[(i + 2 ) % 4 ] ^ tempX[(i + 3 ) % 4 ] ^ rk[i]); } for (i = 0 ;i < 4 ;i ++ ) { Y[i] = tempX[ 3 - i]; }} /* X[4] is PlainText, rk[32] is round Key, Y[4] is CipherText */ void ECB_Decryption(unsigned long X[], unsigned long rk[], unsigned long Y[]){ unsigned long tempX[ 4 ] = { 0 }; int i = 0 ; for (i = 0 ;i < 4 ;i ++ ) { tempX[i] = X[i]; } for (i = 0 ;i < ROUND;i ++ ) { tempX[i % 4 ] ^= T1(tempX[(i + 1 ) % 4 ] ^ tempX[(i + 2 ) % 4 ] ^ tempX[(i + 3 ) % 4 ] ^ rk[( 31 - i)]); } for (i = 0 ;i < 4 ;i ++ ) { Y[i] = tempX[ 3 - i]; }} void main(){ unsigned long key[ 4 ] = { 0x01234567 , 0x89abcdef , 0xfedcba98 , 0x76543210 }; unsigned long roundkey[ 32 ] = { 0 }; unsigned long plaintext[ 4 ] = { 0x01234567 , 0x89abcdef , 0xfedcba98 , 0x76543210 }; unsigned long ciphertext[ 4 ] = { 0 }; unsigned long test[ 4 ] = { 0 }; int i = 0 ; int j = 0 ; Key_Expansion(key,roundkey); for (i = 0 ;i < ROUND;i ++ ) { printf( " rk[ %d ] = x " , i,roundkey[i]); } printf( " Encrypt: " ); ECB_Encryption(plaintext,roundkey,ciphertext); for (i = 0 ;i < 4 ;i ++ ) { printf( " X[ %d ] = x " , i,ciphertext[i]); } printf( " Decrypt: " ); ECB_Decryption(ciphertext,roundkey,test); for (i = 0 ;i < 4 ;i ++ ) { printf( " X[ %d ] = x " , i,test[i]); } printf( " Encrypt 1000000 times: " ); for (i = 0 ;i < 1000000 ;i ++ ) { ECB_Encryption(plaintext,roundkey,ciphertext); for (j = 0 ;j < 4 ;j ++ ) { plaintext[j] = ciphertext[j]; } } for (i = 0 ;i < 4 ;i ++ ) { printf( " Y[ %d ] = x " ,i,ciphertext[i]); }}
