from:http://blog.csdn.net/mao0514/article/details/52930944
SM4是我们自己国家的一个分组密码算法,是国家密码管理局于2012年发布的。网址戳→_→:http://www.cnnic.NET.cn/jscx/mixbz/sm4/
具体的密码标准和算法官方有非常详尽的PDF文档以供查阅,戳→_→:http://218.241.108.63/wiki/images/2/22/SM4%E5%88%86%E7%BB%84%E5%AF%86%E7%A0%81%E7%AE%97%E6%B3%95.pdf
算法的源码实现官方也有相应的示例源码,戳→_→:
http://218.241.108.63/wiki/index.PHP/File:Sm2_sm3_sm4_c%E8%AF%AD%E8%A8%80%E5%AE%9E%E7%8E%B0.zip
先说说啥是分组密码算法:
分组密码算法——国际DES、国产SM4分组密码就是将明文数据按固定长度进行分组,然后在同一密钥控制下逐组进行加密,从而将各个明文分组变换成一个等长的密文分组的密码。其中二进制明文分组的长度称为该分组密码的分组规模。
SM4密码算法的整体结构图如下:
在SM4的源代码中存在如下几个函数:
- void sm4_setkey_enc(sm4_context *ctx,unsigned char key[16])
- void sm4_setkey_dec(sm4_context *ctx,unsigned char key[16])
- void sm4_crypt_ecb( sm4_context *ctx,int mode,int length, unsigned char *input,unsigned char *output)
- void sm4_crypt_cbc( sm4_context *ctx,int mode,int length,unsigned char iv[16],unsigned char *input,unsigned char *output )
- static void sm4_setkey( unsigned long SK[32], unsigned char key[16] )
还有一个非常重要的结构体:sm4_context
- typedef struct
- {
- int mode; /*!< encrypt/decrypt */
- unsigned long sk[32]; /*!< SM4 subkeys */
- }sm4_context;
先说结构体:
sm4_context结构体中的Mode控制是加密还是解密,sk则表示子密钥,也称作轮密钥。
第一个函数: void sm4_setkey_enc(sm4_context *ctx,unsigned char key[16])
这个函数是用来设置加密密钥的,一个参数分别为sm4_context *ctx和一个key。
其内部会调用static void sm4_setkey( unsigned long SK[32], unsigned char key[16] )函数
这个函数是用来设置密钥的,这个函数内部会对当前传入的主密钥进行32轮的迭代,每次迭代的轮密钥都被存放到ctx结构中的sk数组中。
void sm4_setkey_dec(sm4_context *ctx,unsigned char key[16])函数就是解密函数,过程为上述过程的逆序过程。
第二个函数:void sm4_crypt_ecb( sm4_context *ctx,int mode,int length, unsigned char
这个函数的作用是使用ecb模式(ECB(Electronic Codebook,电码本)模式是分组密码的一种最基本的工作模式。同样,sm4_crypt_cbc函数则是使用的CBC模式,也就是分组链接模式)来对内容进行加密,内部也是一个循环,根据length的长度来进行循环,每次循环都调用sm4_one_round进行加密或者解密,到底是加密还是解密,主要是根据第二个参数Mode来进行决定。
以上就是整个SM4算法的函数简介,运用这些函数接口,我们不需要知道内部的具体实现,就可以使用sm4加密算法来对我们的数据进行加解密,十分的方便。
- /*测试代码
- * SM4/SMS4 algorithm test programme
- * 2012-4-21
- */
- #include <string.h>
- #include <stdio.h>
- #include "sm4.h"
- int main()
- {
- unsigned char key[16] = {0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef,0xfe,0xdc,0xba,0x98,0x76,0x54,0x32,0x10};
- unsigned char input[16] = {0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef,0xfe,0xdc,0xba,0x98,0x76,0x54,0x32,0x10};
- unsigned char output[16];
- sm4_context ctx;
- unsigned long i;
- //encrypt standard testing vector
- sm4_setkey_enc(&ctx,key);
- sm4_crypt_ecb(&ctx,1,16,input,output);
- for(i=0;i<16;i++)
- printf("%02x ", output[i]);
- printf(" ");
- //decrypt testing
- 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;
- }
- /**
- * file sm4.h
- */
- #ifndef XYSSL_SM4_H
- #define XYSSL_SM4_H
- #define SM4_ENCRYPT 1
- #define SM4_DECRYPT 0
- /**
- * rief SM4 context structure
- */
- typedef struct
- {
- int mode; /*!< encrypt/decrypt */
- unsigned long sk[32]; /*!< SM4 subkeys */
- }
- sm4_context;
- #ifdef __cplusplus
- extern "C" {
- #endif
- /**
- * rief 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] );
- /**
- * rief 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] );
- /**
- * rief 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);
- #ifdef __cplusplus
- }
- #endif
- #endif /* sm4.h */
- /*
- * SM4 Encryption alogrithm (SMS4 algorithm)
- * GM/T 0002-2012 Chinese National Standard ref:http://www.oscca.gov.cn/
- * thanks to Xyssl
- * thnaks and refers to http://hi.baidu.com/numax/blog/item/80addfefddfb93e4cf1b3e61.html
- * author:goldboar
- * email:goldboar@163.com
- * 2012-4-20
- */
- // Test vector 1
- // plain: 01 23 45 67 89 ab cd ef fe dc ba 98 76 54 32 10
- // key: 01 23 45 67 89 ab cd ef fe dc ba 98 76 54 32 10
- // round key and temp computing result:
- // rk[ 0] = f12186f9 X[ 0] = 27fad345
- // rk[ 1] = 41662b61 X[ 1] = a18b4cb2
- // rk[ 2] = 5a6ab19a X[ 2] = 11c1e22a
- // rk[ 3] = 7ba92077 X[ 3] = cc13e2ee
- // rk[ 4] = 367360f4 X[ 4] = f87c5bd5
- // rk[ 5] = 776a0c61 X[ 5] = 33220757
- // rk[ 6] = b6bb89b3 X[ 6] = 77f4c297
- // rk[ 7] = 24763151 X[ 7] = 7a96f2eb
- // rk[ 8] = a520307c X[ 8] = 27dac07f
- // rk[ 9] = b7584dbd X[ 9] = 42dd0f19
- // rk[10] = c30753ed X[10] = b8a5da02
- // rk[11] = 7ee55b57 X[11] = 907127fa
- // rk[12] = 6988608c X[12] = 8b952b83
- // rk[13] = 30d895b7 X[13] = d42b7c59
- // rk[14] = 44ba14af X[14] = 2ffc5831
- // rk[15] = 104495a1 X[15] = f69e6888
- // rk[16] = d120b428 X[16] = af2432c4
- // rk[17] = 73b55fa3 X[17] = ed1ec85e
- // rk[18] = cc874966 X[18] = 55a3ba22
- // rk[19] = 92244439 X[19] = 124b18aa
- // rk[20] = e89e641f X[20] = 6ae7725f
- // rk[21] = 98ca015a X[21] = f4cba1f9
- // rk[22] = c7159060 X[22] = 1dcdfa10
- // rk[23] = 99e1fd2e X[23] = 2ff60603
- // rk[24] = b79bd80c X[24] = eff24fdc
- // rk[25] = 1d2115b0 X[25] = 6fe46b75
- // rk[26] = 0e228aeb X[26] = 893450ad
- // rk[27] = f1780c81 X[27] = 7b938f4c
- // rk[28] = 428d3654 X[28] = 536e4246
- // rk[29] = 62293496 X[29] = 86b3e94f
- // rk[30] = 01cf72e5 X[30] = d206965e
- // rk[31] = 9124a012 X[31] = 681edf34
- // cypher: 68 1e df 34 d2 06 96 5e 86 b3 e9 4f 53 6e 42 46
- // test vector 2
- // the same key and plain 1000000 times coumpting
- // plain: 01 23 45 67 89 ab cd ef fe dc ba 98 76 54 32 10
- // key: 01 23 45 67 89 ab cd ef fe dc ba 98 76 54 32 10
- // cypher: 59 52 98 c7 c6 fd 27 1f 04 02 f8 04 c3 3d 3f 66
- #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) ] << 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]);
- // #ifdef _DEBUG
- // printf("rk(%02d) = 0x%08x, X(%02d) = 0x%08x ",i,sk[i], i, ulbuf[i+4] );
- // #endif
- 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;
- }
- }