[pycrypto] Ask help for java2python rewrite for AES decrypto

[Joel Edwards]

There is a good implementation available on the AES Crypt website.

Java version overview
http://www.aescrypt.com/java_aes_crypt.html

Download page
https://www.aescrypt.com/download/

A lot of the code is designed around AES Crypt's file format, but as long
as you evaluate that first, you should be able to get a good idea of how to
set things up correctly.

Keep in mind that only 128-bit encryption is available with the standard
Java lib, and AES Crypt is written for 256-bit encryption. So you will need
to either adapt their work to a 128-bit key size, or (assuming no
restrictions apply) download the "Java Cryptography Extension (JCE)
Unlimited Strength Jurisdiction Policy Files" from
Oracle<http://www.oracle.com/technetwork/java/javase/downloads/index.html>
.

Let me know if you have additional questions. You may contact me directly
if you wish, seeing as this is a pycrypto group.

Joel (Via Mobile)

On Dec 28, 2012, at 2:16, "steve.yi" <steve.yi at 139.com> wrote:


Hi Pycryptors,

I got some requests from my clients, his requests are xml formatted
encrypted by AES with Java.

I decide to use pycrypto to decrypt these xml requests. But i am not
familiar with Java.

Someone can help? Thanks a lot. Java codes as follows,


Encrypt.java
============


import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class Encrypt {
public password = "123456";
    public Encrypt(String password) {
super();
this.password = password;
}
/**
     * 加密
     *
     * @param content 需要加密的内容
     * @param password  加密密码
     * @return
     */
    public static byte[] encrypt(String content, String password) {
            try {

                    KeyGenerator kgen = KeyGenerator.getInstance("AES");
//AES密钥生成器
                    //128是密钥的长度  SecureRandom是随机生成数  但是我们需要摄入确定的值
                    kgen.init(128, new
SecureRandom(password.getBytes()));//初始化密钥
                    SecretKey secretKey = kgen.generateKey();
//分组秘密密钥（并为其提供类型安全）
                    byte[] enCodeFormat = secretKey.getEncoded();
                    SecretKeySpec key = new SecretKeySpec(enCodeFormat,
"AES"); //对产生的密钥再进行封装
                    Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                    byte[] byteContent = content.getBytes("utf-8");
 //获得原文utf-8编码格式的字节数
                    cipher.init(Cipher.ENCRYPT_MODE, key);// 加密初始化
Cipher.ENCRYPT_MODE为加密
                    byte[] result = cipher.doFinal(byteContent);  //密码器执行加密
并生成加密字节数组
                    return result; // 加密
            } catch (Exception e) {
                    e.printStackTrace();
            }
            return null;
    }
    /**解密
     * @param content  待解密内容
     * @param password 解密密钥
     * @return
     */
    public static String decrypt(byte[] content, String password) {
            try {
                     KeyGenerator kgen = KeyGenerator.getInstance("AES");
 //AES密钥生成器
                     //128是密钥的长度  SecureRandom是随机生成数  但是我们需要摄入确定的值
                     kgen.init(128, new SecureRandom(password.getBytes()));
 //初始化密钥
                     SecretKey secretKey = kgen.generateKey();
 //分组秘密密钥（并为其提供类型安全）
                     byte[] enCodeFormat = secretKey.getEncoded();
                     SecretKeySpec key = new SecretKeySpec(enCodeFormat,
"AES");  //对产生的密钥再进行封装
                     Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                    cipher.init(Cipher.DECRYPT_MODE, key);// 解密初始化
Cipher.DECRYPT_MODE为解密
                    byte[] result = cipher.doFinal(content);  //密码器执行解密密
并生成解密密字节数组
                    return new String(result); // 解密
            } catch (Exception e) {
                    e.printStackTrace();
            }
            return null;
    }


    public static String parseByte2HexStr(byte buf[]){
    StringBuffer sb=new StringBuffer();
    for(int i=0;i<buf.length;i++){
    String hex=Integer.toHexString(buf[i]&0xFF);
    if(hex.length()==1){
    hex='0' + hex;
    }
    sb.append(hex.toUpperCase());
    }
    return sb.toString();
    }


    public static byte[] parseHexStr2Byte(String hexStr){
    if(hexStr.length()<1)
    return null;
    byte[]result=new byte[hexStr.length()/2];
    for(int i=0;i<hexStr.length()/2;i++){
    int high=Integer.parseInt(hexStr.substring(i*2,i*2+1),16);
    int low=Integer.parseInt(hexStr.substring(i*2+1,i*2+2),16);
    result[i]=(byte)(high*16+low);
    }
    return result;
    }

    public static void main(String args[]) throws
UnsupportedEncodingException {
    String content = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"+
    "<request>"+
      "<company>1</company>"+
    "<requestId>2</requestId>"+
    "<Create>"+
    "<CreateHost>"+
    "<userId>3</userId>"+
    "<transactionId>4</transactionId>"+
    "<timestamp>5</timestamp>"+
    "<core>6</core>"+
    "<memory>7</memory>"+
    "<os>4</os>"+
    "<groupName>5</groupName>"+
    "<hostSpecId>5</hostSpecId>"+
    "<path>6</path>"+
    "</CreateHost>"+
    "<CreateIp>"+
    "<transactionId>6</transactionId>"+
    "<netSpeed>6</netSpeed>"+
    "<ip>7</ip>"+
    "</CreateIp >"+
    "<CreateDisk>"+
    "<transactionId>7</transactionId>"+
    "<disk>7</disk>"+
    "</CreateDisk>"+
    "</Create>"+
    "</request>";
    System.out.println("content:"+content);
     System.out.println("encrypted:"+(parseByte2HexStr(Encrypt.encrypt(content,
"123456"))));
     System.out.println("decrypted:"+Encrypt.decrypt(parseHexStr2Byte(parseByte2HexStr(Encrypt.encrypt(content,
"123456"))),"123456"));
    }


}

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