AES加密【转】

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此时就一定要使用如下代码步骤 :

1.SecureRandom的key定下来.

SecureRandom 实现完全隨操作系统本身的內部狀態，除非調用方在調用 getInstance 方法之後又調用了 setSeed 方法；

该实现在 windows 上每次生成的 key 都相同，但是在 solaris 或部分 linux 系统上则不同.

public static SecretKey getKey(String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance( "AES" );
SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
secureRandom.setSeed(strKey.getBytes());
_generator.init(128,secureRandom);
return _generator.generateKey();
} catch (Exception e) {
throw new RuntimeException( " 初始化密钥出现异常 " );
}
}

2. 16进制转换为2进制互转

* 因为加密后的byte数组是不能强制转换成字符串的，
* 换言之：字符串和byte数组在这种情况下不是互逆的；
* 要避免这种情况，我们需要做一些修订，可以考虑将二进制数据转换成十六进制表示

3. BASE64加解密

这个原因和2有点类似,仿佛有点多余,也许能省下这一步.

4. 如果不这么做

windows上加解密正常，linux上加密正常，解密时发生如下异常：

javax.crypto.BadPaddingException: Given final block not properly padded

at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
at javax.crypto.Cipher.doFinal(DashoA13*..)
at chb.test.crypto.AESUtils.crypt(AESUtils.java:386)
at chb.test.crypto.AESUtils.AesDecrypt(AESUtils.java:254)
at chb.test.crypto.AESUtils.main(AESUtils.java:40)

而我自己遇上的情况比这更糟,同样的windows环境,

用apache的httppost发送加密报文在tomcat服务端进行解密就会报以上异常,

但是用java原生态的UrlConnection发送加密报文在tomcat服务端进行解密一切正常.

可能是apache对发送的流填充模式不同吧@@！

代码示例

package com.testdemo.validate.endecrypt;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom; import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec; import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder; public class AESTool {
private final static String encoding = "UTF-8";
/**
* AES加密
*
* @param content
* @param password
* @return
*/
public static String encryptAES(String content, String password) {
byte[] encryptResult = encrypt(content, password);
String encryptResultStr = parseByte2HexStr(encryptResult);
// BASE64位加密
encryptResultStr = encryptBASE64(encryptResultStr);
return encryptResultStr;
} /**
* AES解密
*
* @param encryptResultStr
* @param password
* @return
*/
public static String decryptAES(String encryptResultStr, String password) {
// BASE64位解密
String decrpt = decryptBASE64(encryptResultStr);
byte[] decryptFrom = parseHexStr2Byte(decrpt);
byte[] decryptResult = decrypt(decryptFrom, password);
return new String(decryptResult);
} /**
* 加密字符串
*/
public static String encryptBASE64(String str) {
BASE64Encoder base64encoder = new BASE64Encoder();
String result = str;
if (str != null && str.length() > 0) {
try {
byte[] encodeByte = str.getBytes(encoding);
result = base64encoder.encode(encodeByte);
} catch (Exception e) {
e.printStackTrace();
}
}
//base64加密超过一定长度会自动换行需要去除换行符
return result.replaceAll("\r\n", "").replaceAll("\r", "").replaceAll("\n", "");
} /**
* 解密字符串
*/
public static String decryptBASE64(String str) {
BASE64Decoder base64decoder = new BASE64Decoder();
try {
byte[] encodeByte = base64decoder.decodeBuffer(str);
return new String(encodeByte);
} catch (IOException e) {
e.printStackTrace();
return str;
}
}
/**
* 加密
*
* @param content 需要加密的内容
* @param password 加密密码
* @return
*/
private static byte[] encrypt(String content, String password) {
try {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
//防止linux下随机生成key
SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
secureRandom.setSeed(password.getBytes());
kgen.init(128, secureRandom);
//kgen.init(128, new SecureRandom(password.getBytes()));
SecretKey secretKey = kgen.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
Cipher cipher = Cipher.getInstance("AES");// 创建密码器
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
byte[] result = cipher.doFinal(byteContent);
return result; // 加密
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
} /**解密
* @param content 待解密内容
* @param password 解密密钥
* @return
*/
private static byte[] decrypt(byte[] content, String password) {
try {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
//防止linux下随机生成key
SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
secureRandom.setSeed(password.getBytes());
kgen.init(128, secureRandom);
//kgen.init(128, new SecureRandom(password.getBytes()));
SecretKey secretKey = kgen.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
Cipher cipher = Cipher.getInstance("AES");// 创建密码器
cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
byte[] result = cipher.doFinal(content);
return result; // 加密
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
} /**将二进制转换成16进制
* @param buf
* @return
*/
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();
} /**将16进制转换为二进制
* @param hexStr
* @return
*/
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 test1() {
String content = "test";
String password = "12345678";
// 加密
System.out.println("加密前：" + content);
String encryptResult = encryptAES(content, password);
System.out.println("加密后: "+ encryptResult);
// 解密
System.out.println("解密前: "+ encryptResult);
String decryptResult = decryptAES(encryptResult, password);
System.out.println("解密后：" + new String(decryptResult));
} public static void main(String[] args) {
test1();
}}