国密SM4对称算法实现说明（原SMS4无线局域网算法标准）

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

 /**
 * \file sm4.h
 */
 #ifndef XYSSL_SM4_H
 #define XYSSL_SM4_H

 #define SM4_ENCRYPT     1
 #define SM4_DECRYPT     0

 /**
 * \brief          SM4 context structure
 */
 typedef struct
 {
     int mode;                   /*!<  encrypt/decrypt   */
     unsigned long sk[];       /*!<  SM4 subkeys       */
 }
 sm4_context;

 #ifdef __cplusplus
 extern "C" {
 #endif

     /**
     * \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[]);

     /**
     * \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[]);

     /**
     * \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[],
         unsigned char *input,
         unsigned char *output);

 #ifdef __cplusplus
 }
 #endif

 #endif /* sm4.h */

　　sm4.c

 #include "sm4.h"
 #include <string.h>
 #include <stdio.h>

 /*
 * 32-bit integer manipulation macros (big endian)
 */
 #ifndef GET_ULONG_BE
 #define GET_ULONG_BE(n,b,i)                             \
 {                                                       \
     (n) = ((unsigned long)(b)[(i)] << )        \
     | ((unsigned long)(b)[(i)+] << )        \
     | ((unsigned long)(b)[(i)+] << )        \
     | ((unsigned long)(b)[(i)+]);       \
 }
 #endif

 #ifndef PUT_ULONG_BE
 #define PUT_ULONG_BE(n,b,i)                             \
 {                                                       \
     (b)[(i)] = (unsigned char)((n) >> );       \
     (b)[(i)+] = (unsigned char)((n) >> );       \
     (b)[(i)+] = (unsigned char)((n) >> );       \
     (b)[(i)+] = (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[][] =
 {
     { 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[] = { 0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc };

 /* fixed parameter */
 static const unsigned long CK[] =
 {
     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 = ;
     unsigned long c = ;
     unsigned char a[];
     unsigned char b[];
     PUT_ULONG_BE(ka, a, )
         b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     GET_ULONG_BE(bb, b, )
         c = bb ^ (ROTL(bb, )) ^ (ROTL(bb, )) ^ (ROTL(bb, )) ^ (ROTL(bb, ));
     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 = ;
     unsigned long rk = ;
     unsigned char a[];
     unsigned char b[];
     PUT_ULONG_BE(ka, a, )
         b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     b[] = sm4Sbox(a[]);
     GET_ULONG_BE(bb, b, )
         rk = bb ^ (ROTL(bb, )) ^ (ROTL(bb, ));
     return rk;
 }

 static void sm4_setkey(unsigned long SK[], unsigned char key[])
 {
     unsigned long MK[];
     unsigned long k[];
     unsigned long i = ;

     GET_ULONG_BE(MK[], key, );
     GET_ULONG_BE(MK[], key, );
     GET_ULONG_BE(MK[], key, );
     GET_ULONG_BE(MK[], key, );
     k[] = MK[] ^ FK[];
     k[] = MK[] ^ FK[];
     k[] = MK[] ^ FK[];
     k[] = MK[] ^ FK[];
     for (; i<; i++)
     {
         k[i + ] = k[i] ^ (sm4CalciRK(k[i + ] ^ k[i + ] ^ k[i + ] ^ CK[i]));
         SK[i] = k[i + ];
     }

 }

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

     memset(ulbuf, , sizeof(ulbuf));
     GET_ULONG_BE(ulbuf[], input, )
         GET_ULONG_BE(ulbuf[], input, )
         GET_ULONG_BE(ulbuf[], input, )
         GET_ULONG_BE(ulbuf[], input, )
     while (i<)
     {
         ulbuf[i + ] = sm4F(ulbuf[i], ulbuf[i + ], ulbuf[i + ], ulbuf[i + ], sk[i]);
         // #ifdef _DEBUG
         //            printf("rk(%02d) = 0x%08x,  X(%02d) = 0x%08x \n",i,sk[i], i, ulbuf[i+4] );
         // #endif
         i++;
     }
     PUT_ULONG_BE(ulbuf[], output, );
     PUT_ULONG_BE(ulbuf[], output, );
     PUT_ULONG_BE(ulbuf[], output, );
     PUT_ULONG_BE(ulbuf[], output, );
 }

 /*
 * SM4 key schedule (128-bit, encryption)
 */
 void sm4_setkey_enc(sm4_context *ctx, unsigned char key[])
 {
     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[])
 {
     int i;
     ctx->mode = SM4_ENCRYPT;
     sm4_setkey(ctx->sk, key);
     for (i = ; i < ; i++)
     {
         SWAP(ctx->sk[i], ctx->sk[ - 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 > )
     {
         sm4_one_round(ctx->sk, input, output);
         input += ;
         output += ;
         length -= ;
     }

 }

 /*
 * SM4-CBC buffer encryption/decryption
 */
 void sm4_crypt_cbc(sm4_context *ctx,
     int mode,
     int length,
     unsigned char iv[],
     unsigned char *input,
     unsigned char *output)
 {
     int i;
     unsigned char temp[];

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

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

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

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

             memcpy(iv, temp, );

             input += ;
             output += ;
             length -= ;
         }
     }
 }

　　sm4test.c

/*
* SM4/SMS4 algorithm test programme
*/

#include <string.h>
#include <stdio.h>
#include "sm4.h"

int main()
{
    unsigned char key[] = { 0xc5, 0x01, 0xcb, 0xe8, 0xa8, 0x49, 0xb3, 0xe7, 0xf6, 0x38, 0xe7, 0xe0, 0x96, 0xe5, 0x60, 0xef };
    unsigned char input[] = { 0x87, 0xca, 0xa0, 0x4a, 0x4b, 0xa7, 0x62, 0x92, 0x50, 0xfb, 0xbe, 0x07, 0x5b, 0xd3, 0x00, 0x01 };

    unsigned char output[];
    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, , , input, output);
    for (i = ; i<; i++)
        printf("%02x ", output[i]); //输出
    printf("\n");

    //decrypt testing
        //数据解密
    sm4_setkey_dec(&ctx, key);
    sm4_crypt_ecb(&ctx, , , output, output);
    for (i = ; i<; i++)
        printf("%02x ", output[i]);
    printf("\n");
    return ;
}