SM4 CBC模式加密的C语言实现

因为工作的关系，最近在研究国密算法，其中无线局域网使用的SM4算法颇为神秘，网上资源也是少的可怜，不过在笔者的努力下，还是成功搞定了。

有感于SM4相关正确资料的稀少，同时也算是自我的学习积累，故写下此文，希望可以帮助后来人少走些弯路。

此处给出的是基于sm4源码及QT4做的SM4_CBC模式加密算法的验证工具，及其源码。

写在前面的话：SM4算法是国密算法中的一种，分ECB和CBC两种模式，ECB简单加密的使用方法，网上可以搜索的到，单次加密明文长度为0到16，而CBC模式网上资源极少，单次加密明文长度为0到32。

在此，分别贴出完整的文件源码供各位参考

#ifndef HEADER_SM4_H
#define HEADER_SM4_H

#ifdef  __cplusplus
extern "C" {
#endif

typedef unsigned char muint8;
typedef unsigned long muint32;

#define LITTLE_ENDIAN     //定义小端字节序
//#define BIG_ENDIAN     //定义大端字节序
#define SM4_ENCRYPT  1     //定义加密标志
#define SM4_DECRYPT  0     //定义解密标志

#define SM4_BLOCK_LEN	16
#define SM4_KEY_LEN	16
#define SM4_IV_LEN	SM4_BLOCK_LEN

// SM4的密钥扩展算法
// 参数说明：Key为加密密钥，rk为子密钥，CryptFlag为加解密标志
int SM4KeyExt(const muint8 *Key, muint32 *rk, muint32 CryptFlag);

// SM4的加解密函数
// 参数说明：Input为输入信息分组，Output为输出分组，rk为轮密钥
int SM4Crypt(const muint8 *Input, muint8 *Output, const muint32 *rk);

//For EVP
void sm4_set_key(muint32 *rk, const unsigned char *data, int enc);
void sm4_ecb_encrypt(char *in,  char *out, const muint32 *rk,
					 int enc);
void sm4_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
					 const muint32 *rk, unsigned char *iv, int enc);
void sm4_cfb64_encrypt(const unsigned char *in, unsigned char *out,
					   long length, const muint32 *rk, unsigned char *ivec,
					   int *num, int enc);
void sm4_ofb64_encrypt(const unsigned char *in, unsigned char *out,
					   long length, const muint32 *rk, unsigned char *ivec,
					   int *num);

#ifdef  __cplusplus
}
#endif

#endif
#include "sm4.h"
#include 

//muint32 rk[32];//作为加解密上下文

const muint8 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
};

const muint32 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 };

#define Rotl(_x, _y) (((_x) << (_y)) | ((_x) >> (32 - (_y))))

#define ByteSub(_A) (Sbox[(_A) >> 24 & 0xFF] << 24 ^ \
                     Sbox[(_A) >> 16 & 0xFF] << 16 ^ \
                     Sbox[(_A) >>  8 & 0xFF] <<  8 ^ \
                     Sbox[(_A) & 0xFF])

#define L1(_B) ((_B) ^ Rotl(_B, 2) ^ Rotl(_B, 10) ^ Rotl(_B, 18) ^ Rotl(_B, 24))
#define L2(_B) ((_B) ^ Rotl(_B, 13) ^ Rotl(_B, 23))

// SM4的加解密函数
// 参数说明：Input为输入信息分组，Output为输出分组，rk为轮密钥
int SM4Crypt(const muint8 *Input, muint8 *Output, const muint32 *rk)
{
	 muint32 r, mid, x0, x1, x2, x3, *p;
	 p = (muint32 *)Input;
	 x0 = p[0];
	 x1 = p[1];
	 x2 = p[2];
	 x3 = p[3];
#ifdef LITTLE_ENDIAN
	 x0 = Rotl(x0, 16); x0 = ((x0 & 0x00FF00FF) << 8) ^ ((x0 & 0xFF00FF00) >> 8);
	 x1 = Rotl(x1, 16); x1 = ((x1 & 0x00FF00FF) << 8) ^ ((x1 & 0xFF00FF00) >> 8);
	 x2 = Rotl(x2, 16); x2 = ((x2 & 0x00FF00FF) << 8) ^ ((x2 & 0xFF00FF00) >> 8);
	 x3 = Rotl(x3, 16); x3 = ((x3 & 0x00FF00FF) << 8) ^ ((x3 & 0xFF00FF00) >> 8);
#endif
	 for (r = 0; r < 32; r += 4)
	 {
		  mid = x1 ^ x2 ^ x3 ^ rk[r + 0];
		  mid = ByteSub(mid);
		  x0 ^= L1(mid);
		  mid = x2 ^ x3 ^ x0 ^ rk[r + 1];
		  mid = ByteSub(mid);
		  x1 ^= L1(mid);
		  mid = x3 ^ x0 ^ x1 ^ rk[r + 2];
		  mid = ByteSub(mid);
		  x2 ^= L1(mid);
		  mid = x0 ^ x1 ^ x2 ^ rk[r + 3];
		  mid = ByteSub(mid);
		  x3 ^= L1(mid);
	 }
#ifdef LITTLE_ENDIAN
	 x0 = Rotl(x0, 16); x0 = ((x0 & 0x00FF00FF) << 8) ^ ((x0 & 0xFF00FF00) >> 8);
	 x1 = Rotl(x1, 16); x1 = ((x1 & 0x00FF00FF) << 8) ^ ((x1 & 0xFF00FF00) >> 8);
	 x2 = Rotl(x2, 16); x2 = ((x2 & 0x00FF00FF) << 8) ^ ((x2 & 0xFF00FF00) >> 8);
	 x3 = Rotl(x3, 16); x3 = ((x3 & 0x00FF00FF) << 8) ^ ((x3 & 0xFF00FF00) >> 8);
#endif
	 p = (muint32 *)Output;
	 p[0] = x3;
	 p[1] = x2;
	 p[2] = x1;
	 p[3] = x0;

	 return 1;
}

// SM4的密钥扩展算法
// 参数说明：Key为加密密钥，rk为子密钥，CryptFlag为加解密标志
int SM4KeyExt(const muint8 *Key, muint32 *rk, muint32 CryptFlag)
{
	 muint32 r, mid, x0, x1, x2, x3, *p;
	 p = (muint32 *)Key;
	 x0 = p[0];
	 x1 = p[1];
	 x2 = p[2];
	 x3 = p[3];
#ifdef LITTLE_ENDIAN
	 x0 = Rotl(x0, 16); x0 = ((x0 & 0xFF00FF) << 8) ^ ((x0 & 0xFF00FF00) >> 8);
	 x1 = Rotl(x1, 16); x1 = ((x1 & 0xFF00FF) << 8) ^ ((x1 & 0xFF00FF00) >> 8);
	 x2 = Rotl(x2, 16); x2 = ((x2 & 0xFF00FF) << 8) ^ ((x2 & 0xFF00FF00) >> 8);
	 x3 = Rotl(x3, 16); x3 = ((x3 & 0xFF00FF) << 8) ^ ((x3 & 0xFF00FF00) >> 8);
#endif
	 x0 ^= 0xa3b1bac6;
	 x1 ^= 0x56aa3350;
	 x2 ^= 0x677d9197;
	 x3 ^= 0xb27022dc;
	 for (r = 0; r < 32; r += 4)
	 {
		  mid = x1 ^ x2 ^ x3 ^ CK[r + 0];
		  mid = ByteSub(mid);
		  rk[r + 0] = x0 ^= L2(mid);
		  mid = x2 ^ x3 ^ x0 ^ CK[r + 1];
		  mid = ByteSub(mid);
		  rk[r + 1] = x1 ^= L2(mid);
		  mid = x3 ^ x0 ^ x1 ^ CK[r + 2];
		  mid = ByteSub(mid);
		  rk[r + 2] = x2 ^= L2(mid);
		  mid = x0 ^ x1 ^ x2 ^ CK[r + 3];
		  mid = ByteSub(mid);
		  rk[r + 3] = x3 ^= L2(mid);
	 }
	 if (CryptFlag == SM4_DECRYPT)
	 {
	 	  for (r = 0; r < 16; r++)
	 	  	 mid = rk[r], rk[r] = rk[31 - r], rk[31 - r] = mid;
	 }

	 return 1;
}

void sm4_xor_private(unsigned char *out, const unsigned char * const input1, 
					 const unsigned char * const input2, const long length)
{
	long i = 0;

	for (i=0; i= SM4_BLOCK_LEN)
		{
			sm4_xor_private(ucInData, pInData, ucIv, SM4_BLOCK_LEN);

			SM4Crypt(ucInData, pOutData, rk);

			memcpy(ucIv, pOutData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}

		if (length == SM4_BLOCK_LEN)
		{
			sm4_xor_private(ucInData, pInData, ucIv, SM4_BLOCK_LEN);

			SM4Crypt(ucInData, pOutData, rk);

			memcpy(ucIv, pOutData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}
	}
	else
	{
		pInData = in;
		pOutData = out;
		memcpy(ucIv, iv, SM4_BLOCK_LEN);
		while (length >= SM4_BLOCK_LEN)
		{
			SM4Crypt(pInData, ucOutData, rk);

			sm4_xor_private(pOutData, ucOutData, ucIv, SM4_BLOCK_LEN);

			memcpy(ucIv, pInData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}

		if (length == SM4_BLOCK_LEN)
		{
			SM4Crypt(pInData, ucOutData, rk);

			sm4_xor_private(pOutData, ucOutData, ucIv, SM4_BLOCK_LEN);

			memcpy(ucIv, pInData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}
	}

	memcpy(iv, ucIv, SM4_BLOCK_LEN);
}

void sm4_cfb64_encrypt(const unsigned char *in, unsigned char *out,
					   long length, const muint32 *rk, unsigned char *ivec,
					   int *num, int enc)
{
	//length must be n*blocksize!!
	unsigned char ucInData[SM4_BLOCK_LEN] = {0};
	unsigned char ucOutData[SM4_BLOCK_LEN] = {0};
	unsigned char ucIv[SM4_BLOCK_LEN] = {0};
	const unsigned char *pInData = NULL;
	unsigned char *pOutData = NULL;

	if (enc)
	{
		pInData = in;
		pOutData = out;
		memcpy(ucIv, ivec, SM4_BLOCK_LEN);
		while (length >= SM4_BLOCK_LEN)
		{
			SM4Crypt(ucIv, ucOutData, rk);

			sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

			memcpy(ucIv, pOutData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}

		if (length == SM4_BLOCK_LEN)
		{
			SM4Crypt(ucIv, ucOutData, rk);

			sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

			memcpy(ucIv, pOutData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}
	}
	else
	{
		pInData = in;
		pOutData = out;
		memcpy(ucIv, ivec, SM4_BLOCK_LEN);
		while (length >= SM4_BLOCK_LEN)
		{
			SM4Crypt(ucIv, ucOutData, rk);

			sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

			memcpy(ucIv, pInData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}

		if (length == SM4_BLOCK_LEN)
		{
			SM4Crypt(ucIv, ucOutData, rk);

			sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

			memcpy(ucIv, pInData, SM4_BLOCK_LEN);
			pInData += SM4_BLOCK_LEN;
			pOutData += SM4_BLOCK_LEN;
			length -= SM4_BLOCK_LEN;
		}
	}

	memcpy(ivec, ucIv, SM4_BLOCK_LEN);
}

void sm4_ofb64_encrypt(const unsigned char *in, unsigned char *out,
					   long length, const muint32 *rk, unsigned char *ivec,
					   int *num)
{
	//length must be n*blocksize!!
	unsigned char ucInData[SM4_BLOCK_LEN] = {0};
	unsigned char ucOutData[SM4_BLOCK_LEN] = {0};
	unsigned char ucIv[SM4_BLOCK_LEN] = {0};
	const unsigned char *pInData = NULL;
	unsigned char *pOutData = NULL;

	pInData = in;
	pOutData = out;
	memcpy(ucIv, ivec, SM4_BLOCK_LEN);
	while (length >= SM4_BLOCK_LEN)
	{
		SM4Crypt(ucIv, ucOutData, rk);

		sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

		memcpy(ucIv, ucOutData, SM4_BLOCK_LEN);
		pInData += SM4_BLOCK_LEN;
		pOutData += SM4_BLOCK_LEN;
		length -= SM4_BLOCK_LEN;
	}

	if (length == SM4_BLOCK_LEN)
	{
		SM4Crypt(ucIv, ucOutData, rk);

		sm4_xor_private(pOutData, pInData, ucOutData, SM4_BLOCK_LEN);

		memcpy(ucIv, ucOutData, SM4_BLOCK_LEN);
		pInData += SM4_BLOCK_LEN;
		pOutData += SM4_BLOCK_LEN;
		length -= SM4_BLOCK_LEN;
	}

	memcpy(ivec, ucIv, SM4_BLOCK_LEN);
}
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
  Q_OBJECT

public:
  explicit MainWindow(QWidget *parent = 0);
  ~MainWindow();

public slots:
  void SM4Make();

private:
  Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "sm4/sm4.h"

#include 

MainWindow::MainWindow(QWidget *parent) :
  QMainWindow(parent),
  ui(new Ui::MainWindow)
{
  ui->setupUi(this);
  connect (ui->pushButton,SIGNAL(clicked()),this,SLOT(SM4Make()));
}

MainWindow::~MainWindow()
{
  delete ui;
}
void MainWindow::SM4Make ()
{
  if(ui->lineEdit->text ().isEmpty () ||
     ui->lineEdit_2->text ().isEmpty () ||
     ui->lineEdit_3->text ().isEmpty ())
  {
    QMessageBox::warning (this,"错误","密钥、向量、明文均不可为空！");
    return;
  }
  //SGD_SMS4_CBC：
  //密钥：
  unsigned char pbCBCKeyValue[16] = {0};
  //初始化向量：
  unsigned char pbCBCIV[16] = {0};
  //明文：
  unsigned char pbCBCPlainText[32] = {0};
  //密文：
  unsigned char pbCBCCipherText[32] = {0};

  unsigned char szRet[128] = {0};
  unsigned long rk[32] = {0};

  QString keyvalue,iv,plaintext,ciphertext,tempstr;
  ciphertext = "";
  keyvalue = ui->lineEdit->text ();
  iv = ui->lineEdit_2->text ();
  plaintext = ui->lineEdit_3->text ();

  unsigned char temp[32] = {};
  int j;
  bool ok;
  for(int i = 0;icheckBox->isChecked ())
  {
    for(int i = 0;ilineEdit_4->setText (ciphertext);
}

另外，想要获得工具及项目整体源码的小伙伴，请在文章下面评论留言留下您的邮箱，笔者看到之后会邮箱发送附件的。

同时，有需要其他相关加密算法如SM3/MD5的，也可以留言，我们共同学习，共同进步！

附上笔者邮箱[email protected]，有需要可以直接发邮件给我

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