AES rijndael在c和java之间加密

Question

AES rijndael在c和java之间加密

den*_*ini 2 c java cryptography aes mcrypt

我对c和Java之间的加密/解密感到疯狂,但到目前为止,Java中的加密字符串和c中的加密字符串看起来并不相同.我已经调查了base64编码/解码但是在疯狂地找到java和c的库后,各自的base64结果看起来不同了!我认为这是在Java UTF16字符串之间进行转换,在java中保存字节或者AES选项(128/256密钥,PK5填充或谁知道什么),或者终端的UTF8转换或上述荒谬组合之间的转换问题.到目前为止,我得到:

  user1@comp1:~/Desktop$ gcc AES.c /usr/lib/libmcrypt.a -lssl -lcrypto -lpthread
  user1@comp1:~/Desktop$ /usr/java/jdk1.6.0_25/bin/javac AES.java
  user1@comp1:~/Desktop$ ./a.out 
      Before encryption: test text 123
      After encryption: 49 -60 66 43 -8 66 -106 0 -14 -44 3 47 65 127 -110 117 
      After decryption: test text 123
  user1@comp1:~/Desktop$ java AES 
     Before encryption: test text 123
     After encryption: -110 21 23 59 47 120 70 -93 -54 -93 -12 -70 -91 83 -113 85 
     After decryption: test text 123

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我认为我真的需要帮助从某人到低级编码,下面分别是Java和c的代码:

import java.security.MessageDigest;
import java.util.Arrays;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.IvParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class AES {
  public static void main(String [] args) {
      try {
  String text = "test text 123";
  /*fixed here now it is 128 bits = 16 Bytes*/
  String encryptionKey = "E072EDF9534053A0";

  System.out.println("Before encryption: " + text);

  byte[] cipher = encrypt(text, encryptionKey);

  System.out.print("After encryption: ");
  for (int i=0; i<cipher.length; i++)
        System.out.print(new Integer(cipher[i])+" ");
  System.out.println("");

  String decrypted = decrypt(cipher, encryptionKey);

  System.out.println("After decryption: " + decrypted);

      } catch (Exception e) {
  e.printStackTrace();
      } 
  }

  public static byte[] encrypt(String plainText, String encryptionKey) throws Exception {
      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "SunJCE");
      SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
      cipher.init(Cipher.ENCRYPT_MODE, key,new IvParameterSpec(new byte[cipher.getBlockSize()]));
      return cipher.doFinal(plainText.getBytes("UTF-8"));
  }

  public static String decrypt(byte[] cipherText, String encryptionKey) throws Exception{
      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "SunJCE");
      SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
      cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(new byte[cipher.getBlockSize()]));
      return new String(cipher.doFinal(cipherText),"UTF-8");
  }
  }

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和

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mcrypt.h>

#include <math.h>
#include <stdint.h>
#include <stdlib.h>

int main()
{
MCRYPT td, td2;
const char * plaintext = "test text 123";
int i;
char *key; /* created using mcrypt_gen_key */
char *IV;
char * block_buffer;
int blocksize;
int keysize = 16; /* 128 bits == 16 bytes */
size_t* sizet;

key = calloc(1, keysize);

/*below dirty trick to be sure the entire key has been padded with \0's */
strcpy(key, "E072EDF9534053A0");
memset(key, '\0', sizeof(key));
strcpy(key, "E072EDF9534053A0");

/*  MCRYPT mcrypt_module_open( char *algorithm, char* algorithm_directory, char* mode, char* mode_directory);
 * This function normally returns an encryption descriptor, or MCRYPT_FAILED on error. 
 */
td = mcrypt_module_open("rijndael-128", NULL, "cbc", NULL);
/*we need two encryption descriptors td and td2 for decryption*/
td2 = mcrypt_module_open("rijndael-128", NULL, "cbc", NULL);

blocksize = mcrypt_enc_get_block_size(td);
block_buffer = calloc(1, blocksize);
/*below to be sure the entire block_buffer has been padded with \0's */
memset(block_buffer, '\0', blocksize);

IV = malloc(mcrypt_enc_get_iv_size(td));
if ((block_buffer == NULL) || (IV == NULL)) {
fprintf(stderr, "Failed to allocate memory\n");
exit(EXIT_FAILURE);
}
for (i = 0; i < mcrypt_enc_get_iv_size(td); i++) {
IV[i] = 0;
}
/*as we can see both td and td2 get same key and IV*/
mcrypt_generic_init(td, key, keysize, IV);
mcrypt_generic_init(td2, key, keysize, IV);

memset(block_buffer, '\0', sizeof(plaintext));
strcpy(block_buffer, plaintext);

printf("Before encryption: %s\n", block_buffer);
mcrypt_generic (td, block_buffer, blocksize);

printf("After encryption: ");
for (i=0; i < blocksize; i++)
    printf("%d ", block_buffer[i]);
printf("\n");

mdecrypt_generic (td2, block_buffer, blocksize);
printf("After decryption: %s\n", block_buffer);

/* deinitialize the encryption thread */
mcrypt_generic_deinit (td);
mcrypt_generic_deinit(td2);
/* Unload the loaded module */
mcrypt_module_close(td);
mcrypt_module_close(td2);
return 0;
}

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Answer 1

bri*_*ice 13

摘要

在解决所有问题后,我得到:

$ ./a.out
==C==
plain:   test text 123
cipher:  16 -124 41 -83 -16 -123 61 -64 -15 -74 87 28 63 30 64 78 
decrypt: test text 123

$java AES
==JAVA==
plain:   test text 123
cipher:  16 -124 41 -83 -16 -123 61 -64 -15 -74 87 28 63 30 64 78 
decrypt: test text 123

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请参阅下面的代码.

问题

错误的密码: AES是Rijndael-128,这是Java加密使用的.但是,您的C代码指定Rijndael-256,它不是AES.来自Mcrypt的文档:

Rijndael [...] AES,如果在128位模式下使用

请记住,当将密码称为CIPHER-XXX时,XXX指的是块大小,而不是密钥长度.实际上,Rijndael-128将接受128,192和256位的密钥.但是,AES严格指的是128位Rijndael.您可以在通常的地方找到更多信息.
内存初始化不正确:您没有在C中正确初始化内存,这会在消息结束和块限制之间留下未定义的字节.
填充不正确:您PKCS5Padding在java代码中指定,但是您没有在C中正确填充明文.PKCS5实际上非常简单,并且在wiki上进行了很好的描述.要使用PKCS#5填充,只需确保每个填充字节等于填充的总长度:
```
... | DD DD DD DD DD DD DD DD | DD DD DD DD 04 04 04 04 |
... | DD DD DD DD DD DD DD DD | DD DD DD DD DD 03 03 03 |
... | DD DD DD DD DD DD DD DD | DD DD DD DD DD DD 02 02 |
etc...
```
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其中DD是数据字节.还有其他填充方法,在别处解释.
密钥处理不正确:从十六进制编码的字符串中提取Java程序的密钥,而在C程序中,直接将十六进制字符串作为密钥.您必须始终为两个程序处理密钥,以提供相同的输出.
两侧的不同初始化向量:两侧需要相同的初始化向量.随机生成你的IV是正确的.然后应该将IV与密文一起传递给另一方进行解密.IV不应重复使用.

示例程序

以下是github上提供的

import java.security.MessageDigest;
import java.util.Arrays;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.IvParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class AES {
  /*
   * Please realise that the following IV is terrible.
   * (As easy to crack as ROT13...)
   * Real situations should use a randomly generated IV.
   */
  static String IV = "AAAAAAAAAAAAAAAA";
  /* 
   * Note null padding on the end of the plaintext.
   */
  static String plaintext = "test text 123\0\0\0"; 
  static String encryptionKey = "0123456789abcdef";
  public static void main(String [] args) {
    try {

      System.out.println("==JAVA==");
      System.out.println("plain:   " + plaintext);

      byte[] cipher = encrypt(plaintext, encryptionKey);

      System.out.print("cipher:  ");
      for (int i=0; i<cipher.length; i++){
        System.out.print(new Integer(cipher[i])+" ");
      }
      System.out.println("");

      String decrypted = decrypt(cipher, encryptionKey);

      System.out.println("decrypt: " + decrypted);

    } catch (Exception e) {
      e.printStackTrace();
    } 
  }

  public static byte[] encrypt(String plainText, String encryptionKey) throws Exception {
    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding", "SunJCE");
    SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
    cipher.init(Cipher.ENCRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
    return cipher.doFinal(plainText.getBytes("UTF-8"));
  }

  public static String decrypt(byte[] cipherText, String encryptionKey) throws Exception{
    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding", "SunJCE");
    SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
    cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
    return new String(cipher.doFinal(cipherText),"UTF-8");
  }
}

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和C文件:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*
 * MCrypt API available online:
 * http://linux.die.net/man/3/mcrypt
 */
#include <mcrypt.h>

#include <math.h>
#include <stdint.h>
#include <stdlib.h>

int encrypt(
    void* buffer,
    int buffer_len, /* Because the plaintext could include null bytes*/
    char* IV, 
    char* key,
    int key_len 
){
  MCRYPT td = mcrypt_module_open("rijndael-128", NULL, "cbc", NULL);
  int blocksize = mcrypt_enc_get_block_size(td);
  if( buffer_len % blocksize != 0 ){return 1;}

  mcrypt_generic_init(td, key, key_len, IV);
  mcrypt_generic(td, buffer, buffer_len);
  mcrypt_generic_deinit (td);
  mcrypt_module_close(td);

  return 0;
}


int decrypt(
    void* buffer,
    int buffer_len,
    char* IV, 
    char* key,
    int key_len 
){
  MCRYPT td = mcrypt_module_open("rijndael-128", NULL, "cbc", NULL);
  int blocksize = mcrypt_enc_get_block_size(td);
  if( buffer_len % blocksize != 0 ){return 1;}

  mcrypt_generic_init(td, key, key_len, IV);
  mdecrypt_generic(td, buffer, buffer_len);
  mcrypt_generic_deinit (td);
  mcrypt_module_close(td);

  return 0;
}

void display(char* ciphertext, int len){
  int v;
  for (v=0; v<len; v++){
    printf("%d ", ciphertext[v]);
  }
  printf("\n");
}

int main()
{
  MCRYPT td, td2;
  char * plaintext = "test text 123";
  char* IV = "AAAAAAAAAAAAAAAA";
  char *key = "0123456789abcdef";
  int keysize = 16; /* 128 bits */
  char* buffer;
  int buffer_len = 16;

  buffer = calloc(1, buffer_len);
  /* 
   * Note that calloc() will null-initialise the memory. (Null padding)
   */

  strncpy(buffer, plaintext, buffer_len);

  printf("==C==\n");
  printf("plain:   %s\n", plaintext);
  encrypt(buffer, buffer_len, IV, key, keysize); 
  printf("cipher:  "); display(buffer , buffer_len);
  decrypt(buffer, buffer_len, IV, key, keysize);
  printf("decrypt: %s\n", buffer);

  return 0;
}

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在Linux上使用最新的Libmcrypt和Java 1.7进行测试.注意,因为我急忙写了C,并且它充满了内存泄漏和溢出问题.(练习留给读者清理,就像他们说的那样......)

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