Java加密系列之（四）对称加密算法，java加密算法

来源： javaer 分享于 2019-10-25 点击 30633 次点评：79

Java加密系列之（四）对称加密算法，java加密算法

对称加密算法，是目前应用范围最广，使用频率最高的加密算法

加密密钥=解密密钥，所以叫对称加密算法。

初等：安全性不是那么高

DES

——密钥长度不够，衍生出3重des，即3DES

AES

PBE

IDEA

对称加密算法——DES

DES（Data Encryption Standard）数据加密标准

官方出身，98年已被破解

目前一般已不被使用，当做一些案例（教科书）或者遗留的很老的系统中还在使用

在对称加解密的发展过程中地位很高，有必要介绍下

加解密过程：

1.发送者构建密钥；

2.发送者公布密钥给接收者；

3.发送者使用密钥对数据加密；

4.发送者发送加密数据到接收者；

5.接收者使用密钥对数据解密。

package com.tvm.mrz.security.des;

import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class DESTest {

	private static String src = "Mr.Z Security Base64";

	public static void jdkDES() {
		try {
			// 生成KEY
			KeyGenerator keyGenerator = KeyGenerator.getInstance( "DES" );
			keyGenerator.init( 56 );
			SecretKey secretKey = keyGenerator.generateKey();
			byte[] bytesKey = secretKey.getEncoded();

			// KEY转换
			DESKeySpec desKeySpec = new DESKeySpec( bytesKey );
			SecretKeyFactory factory = SecretKeyFactory.getInstance( "DES" );
			SecretKey resultSecretKey = factory.generateSecret( desKeySpec );

			// 加密
			Cipher cipher = Cipher.getInstance( "DES/ECB/PKCS5Padding" );
			cipher.init( Cipher.ENCRYPT_MODE, resultSecretKey );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "JDK DES ENCRYPT: " + Hex.encodeHexString( result ) );

			// 加密
			cipher.init( Cipher.DECRYPT_MODE, resultSecretKey );
			result = cipher.doFinal( result );
			System.out.println( "JDK DES DECRYPT: " + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void bcDES() {
		try {
			Security.addProvider( new BouncyCastleProvider() );

			// 生成KEY
			KeyGenerator keyGenerator = KeyGenerator.getInstance( "DES", "BC" );
			keyGenerator.init( 56 );
			SecretKey secretKey = keyGenerator.generateKey();
			byte[] bytesKey = secretKey.getEncoded();

			// KEY转换
			DESKeySpec desKeySpec = new DESKeySpec( bytesKey );
			SecretKeyFactory factory = SecretKeyFactory.getInstance( "DES" );
			SecretKey resultSecretKey = factory.generateSecret( desKeySpec );

			// 加密
			Cipher cipher = Cipher.getInstance( "DES/ECB/PKCS5Padding" );
			cipher.init( Cipher.ENCRYPT_MODE, resultSecretKey );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "BC DES ENCRYPT: " + Hex.encodeHexString( result ) );

			// 加密
			cipher.init( Cipher.DECRYPT_MODE, resultSecretKey );
			result = cipher.doFinal( result );
			System.out.println( "BC DES DECRYPT: " + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void main( String[] args ) {
		jdkDES();
		bcDES();
	}
}

对称加密算法——3重DES

好处：

1.密钥长度增强

2.迭代次数提高

package com.tvm.mrz.security.des;

import java.security.SecureRandom;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;

import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class DES3Test {

	private static String src = "Mr.Z Security Base64";

	public static void jdk3DES() {
		try {
			// 生成KEY
			KeyGenerator keyGenerator = KeyGenerator.getInstance( "DESede" );
//			keyGenerator.init( 168 );
			keyGenerator.init( new SecureRandom() );
			SecretKey secretKey = keyGenerator.generateKey();
			byte[] bytesKey = secretKey.getEncoded();

			// KEY转换
			DESedeKeySpec desKeySpec = new DESedeKeySpec( bytesKey );
			SecretKeyFactory factory = SecretKeyFactory.getInstance( "DESede" );
			SecretKey resultSecretKey = factory.generateSecret( desKeySpec );

			// 加密
			Cipher cipher = Cipher.getInstance( "DESede/ECB/PKCS5Padding" );
			cipher.init( Cipher.ENCRYPT_MODE, resultSecretKey );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "JDK 3DES ENCRYPT: " + Hex.encodeHexString( result ) );

			// 加密
			cipher.init( Cipher.DECRYPT_MODE, resultSecretKey );
			result = cipher.doFinal( result );
			System.out.println( "JDK 3DES DECRYPT: " + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void bc3DES() {
		try {
			Security.addProvider( new BouncyCastleProvider() );

			// 生成KEY
			KeyGenerator keyGenerator = KeyGenerator.getInstance( "DESede", "BC" );
			keyGenerator.init( 168 );
			SecretKey secretKey = keyGenerator.generateKey();
			byte[] bytesKey = secretKey.getEncoded();

			// KEY转换
			DESedeKeySpec desKeySpec = new DESedeKeySpec( bytesKey );
			SecretKeyFactory factory = SecretKeyFactory.getInstance( "DESede" );
			SecretKey resultSecretKey = factory.generateSecret( desKeySpec );

			// 加密
			Cipher cipher = Cipher.getInstance( "DESede/ECB/PKCS5Padding" );
			cipher.init( Cipher.ENCRYPT_MODE, resultSecretKey );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "BC 3DES ENCRYPT: " + Hex.encodeHexString( result ) );

			// 加密
			cipher.init( Cipher.DECRYPT_MODE, resultSecretKey );
			result = cipher.doFinal( result );
			System.out.println( "BC 3DES DECRYPT: " + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void main( String[] args ) {
		jdk3DES();
		bc3DES();
	}
}

对称加密算法——AES

AES是目前使用最多的对称加密算法

通常用于移动通信系统加密以及基于SSH协议的软件。如：SSH Client、secureCRT

特点：

高级

DES替代者

package com.tvm.mrz.security.aes;

import java.security.Key;

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

import org.apache.commons.codec.binary.Base64;

public class AESTest {

	private static String src = "Mr.Z Security AES";

	public static void jdkAES() {
		try {
			// 生成KEY
			KeyGenerator keyGenerator = KeyGenerator.getInstance( "AES" );
			keyGenerator.init( 128 );
			SecretKey secretKey = keyGenerator.generateKey();
			byte[] bytesKey = secretKey.getEncoded();

			// KEY转换
			Key key = new SecretKeySpec( bytesKey, "AES" );

			// 加密
			Cipher cipher = Cipher.getInstance( "AES/ECB/PKCS5Padding" );
			cipher.init( Cipher.ENCRYPT_MODE, key );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "JDK AES ENCRYPT: " + Base64.encodeBase64String( result ) );

			// 加密
			cipher.init( Cipher.DECRYPT_MODE, key );
			result = cipher.doFinal( result );
			System.out.println( "JDK AES DECRYPT: " + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void bcAES() {
		// TODO
		// 和DES的bc实现都类似
	}

	public static void main( String[] args ) {
		jdkAES();
		bcAES();
	}
}

对称加密算法——PBE

AES、DES和3重DES在使用上比较一致

PBE是一个另类，它综合了消息摘要算法和对称加密算法的优点，形成了一个特殊的对称加密算法

PBE（Password Based Encryption）基于口令加密

对已有算法的包装，如PBEWithMD5AndDES

加解密过程：

1.发送者构建口令；

2.发送者公布口令给接收者；

3.发送者构建盐；

4.发送者使用口令、盐对数据加密；

5.发送者发送盐、加密数据到接收者；

6.接收者使用口令、盐对数据解密。

package com.tvm.mrz.security.pbe;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

import org.apache.commons.codec.binary.Base64;

public class PBETest {

	private static String src = "Mr.Z Security PBE";

	public static void jdkPBE() {
		try {
			// 初始化盐
			SecureRandom random = new SecureRandom();
			byte[] salt = random.generateSeed( 8 );

			// 口令与密钥
			String password = "Mr.Z";
			PBEKeySpec pbeKeySpec = new PBEKeySpec( password.toCharArray() );
			SecretKeyFactory factory = SecretKeyFactory.getInstance( "PBEWithMD5AndDES" );
			Key key = factory.generateSecret( pbeKeySpec );

			// 加密
			PBEParameterSpec pbeParameterSpec = new PBEParameterSpec( salt, 100 );
			Cipher cipher = Cipher.getInstance( "PBEWithMD5AndDES" );
			cipher.init( Cipher.ENCRYPT_MODE, key, pbeParameterSpec );
			byte[] result = cipher.doFinal( src.getBytes() );
			System.out.println( "jdk pbe ENCRYPT:" + Base64.encodeBase64String( result ) );

			// 解密
			cipher.init( Cipher.DECRYPT_MODE, key, pbeParameterSpec );
			result = cipher.doFinal( result );
			System.out.println( "jdk pbe DECRYPT:" + new String( result ) );
		} catch( Exception e ) {
			e.printStackTrace();
		}
	}

	public static void main( String[] args ) {
		jdkPBE();
	}
}

Java加密系列之（四）对称加密算法，java加密算法