[C++知识库]Android中利用C语言进行AES加解密

我们开发中难免遇到加解密的操作。用java开发习惯了，也都有过相关的经验，比如我之前的博文就有介绍过各种利用java如何进行加解密的操作。但我竟然没有说AES怎么加解密。好吧，今天正好书里学习了，就总结一波用C语言的AES加密。

多余的JNI相关调用方法我就不写了，按照之前的步骤来就得了，我直接贴相关C语言的代码和Activity中调用

1.首先是jni文件夹中的四个C语言文件

aes.cpp

#include "aes.h"

AES::AES(unsigned char* key)
{
  unsigned char sBox[] =
  { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
    0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, /*0*/
    0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, /*1*/
    0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, /*2*/
    0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, /*3*/
    0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, /*4*/
    0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, /*5*/
    0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, /*6*/
    0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, /*7*/
    0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, /*8*/
    0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, /*9*/
    0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, /*a*/
    0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, /*b*/
    0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, /*c*/
    0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, /*d*/
    0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, /*e*/
    0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16 /*f*/
  };
  unsigned char invsBox[256] =
  { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
    0x52,0x09,0x6a,0xd5,0x30,0x36,0xa5,0x38,0xbf,0x40,0xa3,0x9e,0x81,0xf3,0xd7,0xfb, /*0*/
    0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87,0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb, /*1*/
    0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d,0xee,0x4c,0x95,0x0b,0x42,0xfa,0xc3,0x4e, /*2*/
    0x08,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2,0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25, /*3*/
    0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16,0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92, /*4*/
    0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda,0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84, /*5*/
    0x90,0xd8,0xab,0x00,0x8c,0xbc,0xd3,0x0a,0xf7,0xe4,0x58,0x05,0xb8,0xb3,0x45,0x06, /*6*/
    0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0x0f,0x02,0xc1,0xaf,0xbd,0x03,0x01,0x13,0x8a,0x6b, /*7*/
    0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea,0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73, /*8*/
    0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85,0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e, /*9*/
    0x47,0xf1,0x1a,0x71,0x1d,0x29,0xc5,0x89,0x6f,0xb7,0x62,0x0e,0xaa,0x18,0xbe,0x1b, /*a*/
    0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20,0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4, /*b*/
    0x1f,0xdd,0xa8,0x33,0x88,0x07,0xc7,0x31,0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f, /*c*/
    0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0x0d,0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef, /*d*/
    0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0,0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61, /*e*/
    0x17,0x2b,0x04,0x7e,0xba,0x77,0xd6,0x26,0xe1,0x69,0x14,0x63,0x55,0x21,0x0c,0x7d /*f*/
  };
  memcpy(Sbox, sBox, 256);
  memcpy(InvSbox, invsBox, 256);
  KeyExpansion(key, ww);
}

AES::~AES()
{

}

void AES::Cipher(char *input, char *output)
{
  unsigned char uch_input[1024] = {0};
  strToUChar(input, uch_input);
  Cipher(uch_input);
  ucharToHex(uch_input,output);
}

void AES::InvCipher(char *input, char *output)
{
  unsigned char uch_input[1024] = {0};
  hexToUChar(input, uch_input);
  InvCipher(uch_input);
  ucharToStr(uch_input, output);
}

unsigned char* AES::Cipher(unsigned char* input)
{
  unsigned char state[4][4];
  int i,r,c;

  for(r=0; r<4; r++)
  {
    for(c=0; c<4 ;c++)
    {
      state[r][c] = input[c*4+r];
    }
  }

  AddRoundKey(state,ww[0]);

  for(i=1; i<=10; i++)
  {
    SubBytes(state);
    ShiftRows(state);
    if(i!=10)MixColumns(state);
    AddRoundKey(state,ww[i]);
  }

  for(r=0; r<4; r++)
  {
    for(c=0; c<4 ;c++)
    {
      input[c*4+r] = state[r][c];
    }
  }

  return input;
}

unsigned char* AES::InvCipher(unsigned char* input)
{
  unsigned char state[4][4];
  int i,r,c;

  for(r=0; r<4; r++)
  {
    for(c=0; c<4 ;c++)
    {
      state[r][c] = input[c*4+r];
    }
  }

  AddRoundKey(state, ww[10]);
  for(i=9; i>=0; i--)
  {
    InvShiftRows(state);
    InvSubBytes(state);
    AddRoundKey(state, ww[i]);
    if(i)
    {
      InvMixColumns(state);
    }
  }

  for(r=0; r<4; r++)
  {
    for(c=0; c<4 ;c++)
    {
      input[c*4+r] = state[r][c];
    }
  }

  return input;
}

void* AES::Cipher(void* input, int length)
{
  unsigned char* in = (unsigned char*) input;
  int i;
  if(!length)
  {
    while(*(in+length++));
    in = (unsigned char*) input;
  }
  for(i=0; i<length; i+=16)
  {
    Cipher(in+i);
  }
  return input;
}

void* AES::InvCipher(void* input, int length)
{
  unsigned char* in = (unsigned char*) input;
  int i;
  for(i=0; i<length; i+=16)
  {
    InvCipher(in+i);
  }
  return input;
}

void AES::KeyExpansion(unsigned char* key, unsigned char www[][4][4])
{
  int i,j,r,c;
  unsigned char rc[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36};
  for(r=0; r<4; r++)
  {
    for(c=0; c<4; c++)
    {
      www[0][r][c] = key[r+c*4];
    }
  }
  for(i=1; i<=10; i++)
  {
    for(j=0; j<4; j++)
    {
      unsigned char t[4];
      for(r=0; r<4; r++)
      {
        t[r] = j ? www[i][r][j-1] : www[i-1][r][3];
      }
      if(j == 0)
      {
        unsigned char temp = t[0];
        for(r=0; r<3; r++)
        {
          t[r] = Sbox[t[(r+1)%4]];
        }
        t[3] = Sbox[temp];
        t[0] ^= rc[i-1];
      }
      for(r=0; r<4; r++)
      {
        www[i][r][j] = www[i-1][r][j] ^ t[r];
        if (i == 10) {
        }
      }
    }
  }
}

unsigned char AES::FFmul(unsigned char a, unsigned char b)
{
  unsigned char bw[4];
  unsigned char res=0;
  int i;
  bw[0] = b;
  for(i=1; i<4; i++)
  {
    bw[i] = bw[i-1]<<1;
    if(bw[i-1]&0x80)
    {
      bw[i]^=0x1b;
    }
  }
  for(i=0; i<4; i++)
  {
    if((a>>i)&0x01)
    {
      res ^= bw[i];
    }
  }
  return res;
}

void AES::SubBytes(unsigned char state[][4])
{
  int r,c;
  for(r=0; r<4; r++)
  {
    for(c=0; c<4; c++)
    {
      state[r][c] = Sbox[state[r][c]];
    }
  }
}

void AES::ShiftRows(unsigned char state[][4])
{
  unsigned char t[4];
  int r,c;
  for(r=1; r<4; r++)
  {
    for(c=0; c<4; c++)
    {
      t[c] = state[r][(c+r)%4];
    }
    for(c=0; c<4; c++)
    {
      state[r][c] = t[c];
    }
  }
}

void AES::MixColumns(unsigned char state[][4])
{
  unsigned char t[4];
  int r,c;
  for(c=0; c< 4; c++)
  {
    for(r=0; r<4; r++)
    {
      t[r] = state[r][c];
    }
    for(r=0; r<4; r++)
    {
      state[r][c] = FFmul(0x02, t[r])
            ^ FFmul(0x03, t[(r+1)%4])
            ^ FFmul(0x01, t[(r+2)%4])
            ^ FFmul(0x01, t[(r+3)%4]);
    }
  }
}

void AES::AddRoundKey(unsigned char state[][4], unsigned char k[][4])
{
  int r,c;
  for(c=0; c<4; c++)
  {
    for(r=0; r<4; r++)
    {
      state[r][c] ^= k[r][c];
    }
  }
}

void AES::InvSubBytes(unsigned char state[][4])
{
  int r,c;
  for(r=0; r<4; r++)
  {
    for(c=0; c<4; c++)
    {
      state[r][c] = InvSbox[state[r][c]];
    }
  }
}

void AES::InvShiftRows(unsigned char state[][4])
{
  unsigned char t[4];
  int r,c;
  for(r=1; r<4; r++)
  {
    for(c=0; c<4; c++)
    {
      t[c] = state[r][(c-r+4)%4];
    }
    for(c=0; c<4; c++)
    {
      state[r][c] = t[c];
    }
  }
}

void AES::InvMixColumns(unsigned char state[][4])
{
  unsigned char t[4];
  int r,c;
  for(c=0; c< 4; c++)
  {
    for(r=0; r<4; r++)
    {
      t[r] = state[r][c];
    }
    for(r=0; r<4; r++)
    {
      state[r][c] = FFmul(0x0e, t[r])
            ^ FFmul(0x0b, t[(r+1)%4])
            ^ FFmul(0x0d, t[(r+2)%4])
            ^ FFmul(0x09, t[(r+3)%4]);
    }
  }
}

int AES::getUCharLen(const unsigned char *uch)
{
  int len = 0;
  while(*uch++)
    ++len;

  return len;
}

int AES::ucharToHex(const unsigned char *uch, char *hex)
{
  int high,low;
  int tmp = 0;
  if(uch == NULL || hex == NULL){
    return -1;
  }

  if(getUCharLen(uch) == 0){
    return -2;
  }

  while(*uch){
    tmp = (int)*uch;
    high = tmp >> 4;
    low = tmp & 15;
    *hex++ = valueToHexCh(high); //先写高字节
    *hex++ = valueToHexCh(low); //其次写低字节
    uch++;
  }
  *hex = '\0';
  return 0;
}

int AES::hexToUChar(const char *hex, unsigned char *uch)
{
  int high,low;
  int tmp = 0;
  if(hex == NULL || uch == NULL){
    return -1;
  }

  if(strlen(hex) %2 == 1){
    return -2;
  }

  while(*hex){
    high = ascillToValue(*hex);
    if(high < 0){
      *uch = '\0';
      return -3;
    }
    hex++; //指针移动到下一个字符上
    low = ascillToValue(*hex);
    if(low < 0){
      *uch = '\0';
      return -3;
    }
    tmp = (high << 4) + low;
    *uch++ = tmp;
    hex++;
  }
  *uch = (int)'\0';
  return 0;
}

int AES::strToUChar(const char *ch, unsigned char *uch)
{
  int tmp = 0;
  if(ch == NULL || uch == NULL)
    return -1;
  if(strlen(ch) == 0)
    return -2;

  while(*ch){
    tmp = (int)*ch;
    *uch++ = tmp;
    ch++;
  }
  *uch = (int)'\0';
  return 0;
}

int AES::ucharToStr(const unsigned char *uch, char *ch)
{
  int tmp = 0;
  if(uch == NULL || ch == NULL)
    return -1;

  while(*uch){
    tmp = (int)*uch;
    *ch++ = (char)tmp;
    uch++;
  }
  *ch = '\0';

  return 0;
}

int AES::strToHex(const char *ch, char *hex)
{
  int high,low;
  int tmp = 0;
  if(ch == NULL || hex == NULL){
    return -1;
  }

  if(strlen(ch) == 0){
    return -2;
  }

  while(*ch){
    tmp = (int)*ch;
    high = tmp >> 4;
    low = tmp & 15;
    *hex++ = valueToHexCh(high); //先写高字节
    *hex++ = valueToHexCh(low); //其次写低字节
    ch++;
  }
  *hex = '\0';
  return 0;
}

int AES::hexToStr(const char *hex, char *ch)
{
  int high,low;
  int tmp = 0;
  if(hex == NULL || ch == NULL){
    return -1;
  }

  if(strlen(hex) %2 == 1){
    return -2;
  }

  while(*hex){
    high = ascillToValue(*hex);
    if(high < 0){
      *ch = '\0';
      return -3;
    }
    hex++; //指针移动到下一个字符上
    low = ascillToValue(*hex);
    if(low < 0){
      *ch = '\0';
      return -3;
    }
    tmp = (high << 4) + low;
    *ch++ = (char)tmp;
    hex++;
  }
  *ch = '\0';
  return 0;
}

int AES::ascillToValue(const char ch){
  int result = 0;
  //获取16进制的高字节位数据
  if(ch >= '0' && ch <= '9'){
    result = (int)(ch - '0');
  }
  else if(ch >= 'a' && ch <= 'z'){
    result = (int)(ch - 'a') + 10;
  }
  else if(ch >= 'A' && ch <= 'Z'){
    result = (int)(ch - 'A') + 10;
  }
  else{
    result = -1;
  }
  return result;
}

char AES::valueToHexCh(const int value)
{
  char result = '\0';
  if(value >= 0 && value <= 9){
    result = (char)(value + 48); //48为ascii编码的‘0’字符编码值
  }
  else if(value >= 10 && value <= 15){
    result = (char)(value - 10 + 65); //减去10则找出其在16进制的偏移量，65为ascii的'A'的字符编码值
  }
  else{
    ;
  }

  return result;
}

aes.h

#ifndef AES_H
#define AES_H

#include <string.h>

class AES
{
public:
  AES(unsigned char* key);
  virtual ~AES();
  unsigned char* Cipher(unsigned char* input);
  unsigned char* InvCipher(unsigned char* input);
  void* Cipher(void* input, int length=0);
  void* InvCipher(void* input, int length);

  void Cipher(char *input, char *output);
  void InvCipher(char *inut, char *output);

private:
  unsigned char Sbox[256];
  unsigned char InvSbox[256];
  unsigned char ww[11][4][4];

  void KeyExpansion(unsigned char* key, unsigned char w[][4][4]);
  unsigned char FFmul(unsigned char a, unsigned char b);

  void SubBytes(unsigned char state[][4]);
  void ShiftRows(unsigned char state[][4]);
  void MixColumns(unsigned char state[][4]);
  void AddRoundKey(unsigned char state[][4], unsigned char k[][4]);

  void InvSubBytes(unsigned char state[][4]);
  void InvShiftRows(unsigned char state[][4]);
  void InvMixColumns(unsigned char state[][4]);

  int strToHex(const char *ch, char *hex);
  int hexToStr(const char *hex, char *ch);
  int ascillToValue(const char ch);
  char valueToHexCh(const int value);
  int getUCharLen(const unsigned char *uch);
  int strToUChar(const char *ch, unsigned char *uch);
  int ucharToStr(const unsigned char *uch, char *ch);
  int ucharToHex(const unsigned char *uch, char *hex);
  int hexToUChar(const char *hex, unsigned char *uch);
};

#endif // AES_H

get_decrypt.cpp

#include <jni.h>
#include <string.h>
#include <stdio.h>
#include "aes.h"
#include <android/log.h>

// log标签
#define TAG "MyMsg"
// 定义info信息
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG,__VA_ARGS__)

extern "C"

jstring
Java_com_longway_cmake2_MainActivity_decryptFromJNI( JNIEnv* env, jobject thiz, jstring des, jstring key)
{
	const char* str_des;
	const char* str_key;
	str_des = env->GetStringUTFChars(des, 0);
	str_key = env->GetStringUTFChars(key, 0);
	LOGI("str_des=%s", str_des);
	LOGI("str_key=%s", str_key);
	char decrypt[1024] = {0};
	AES aes_de((unsigned char*)str_key);
	aes_de.InvCipher((char*)str_des, decrypt);
	LOGI("decrypt=%s", decrypt);
	return env->NewStringUTF(decrypt);
}

get_encrypt.cpp
?

#include <jni.h>
#include <string.h>
#include <stdio.h>
#include "aes.h"
#include <android/log.h>

// log标签
#define TAG "MyMsg"
// 定义info信息
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG,__VA_ARGS__)

extern "C"

jstring
Java_com_longway_cmake2_MainActivity_encryptFromJNI( JNIEnv* env, jobject thiz, jstring raw, jstring key)
{
	const char* str_raw;
	const char* str_key;
	str_raw = env->GetStringUTFChars(raw, 0);
	str_key = env->GetStringUTFChars(key, 0);
	LOGI("str_raw=%s", str_raw);
	LOGI("str_key=%s", str_key);
	char encrypt[1024] = {0};
	AES aes_en((unsigned char*)str_key);
	aes_en.Cipher((char*)str_raw, encrypt);
	LOGI("encrypt=%s", encrypt);
	return env->NewStringUTF(encrypt);
}

2.接着是我们的Android.mk

Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)

# 指定so库文件的名称
LOCAL_MODULE    := jni_mix
# 指定需要编译的源文件列表
LOCAL_SRC_FILES := get_decrypt.cpp get_encrypt.cpp aes.cpp
# 指定C++的编译标志
LOCAL_CPPFLAGS += -fexceptions
# 指定要加载的静态库
#LOCAL_WHOLE_STATIC_LIBRARIES += android_support
# 指定需要链接的库
LOCAL_LDLIBS    := -llog

include $(BUILD_SHARED_LIBRARY)
$(call import-module, android/support)

3.Activity中我们的内容

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private EditText et_origin; // 声明一个用于输入原始字符串的编辑框对象
    private EditText et_encrypt; // 声明一个用于输入加密字符串的编辑框对象
    private TextView tv_decrypt;
    private String mKey = "123456789abcdef"; // 该算法要求密钥串的长度为16位

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_origin = findViewById(R.id.et_origin);
        et_encrypt = findViewById(R.id.et_encrypt);
        tv_decrypt = findViewById(R.id.tv_decrypt);
        findViewById(R.id.btn_encrypt).setOnClickListener(this);
        findViewById(R.id.btn_decrypt).setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btn_encrypt) { // 点击了加密按钮
            // 调用JNI方法encryptFromJNI获得加密后的字符串
            String des = encryptFromJNI(et_origin.getText().toString(), mKey);
            et_encrypt.setText(des);
        } else if (v.getId() == R.id.btn_decrypt) { // 点击了解密按钮
            // 调用JNI方法decryptFromJNI获得解密后的字符串
            String raw = decryptFromJNI(et_encrypt.getText().toString(), mKey);
            tv_decrypt.setText(raw);
        }
    }

    // 声明encryptFromJNI是来自于JNI的原生方法
    public native String encryptFromJNI(String raw, String key);

    // 声明decryptFromJNI是来自于JNI的原生方法
    public native String decryptFromJNI(String des, String key);

    // 在加载当前类时就去加载jni_mix.so，加载动作发生在页面启动之前
    static {
        System.loadLibrary("jni_mix");
    }
}

这样就使用C语言完成了AES加密操作。