Java加解密——Base64与DES

一、BASE64

这里选用Java自带的BASE64Encoder和BASE64Decoder进行BASE64编码，除此之外，可以选择commons-codec.jar等第三方jar包进行实现。

BASE64Encoder和BASE64Decoder为实现BASE64的API，为了解决高并发问题，提高运行效率，本例将encoder和decoder作为全局静态属性，并通过ThreadLocal进行管理。

package com.fhp.testencrypt;

import sun.misc.BASE64Encoder;
import java.io.IOException;
import sun.misc.BASE64Decoder;

public class Base64Utils {

private static ThreadLocal<BASE64Encoder> encoder = new ThreadLocal<BASE64Encoder>() {
@Override
protected BASE64Encoder initialValue() {
return new BASE64Encoder();
}
};

private static ThreadLocal<BASE64Decoder> decoder = new ThreadLocal<BASE64Decoder>() {
@Override
protected BASE64Decoder initialValue() {
return new BASE64Decoder();
}
};

public static String encode(byte[] bytes) {
return encoder.get().encode(bytes);
}

public static byte[] decode(String str) {
try {
return decoder.get().decodeBuffer(str);
} catch (IOException e) {
throw new RuntimeException("Cannot decode string:" + str, e);
}
}
}

二、DES

package com.fhp.testencrypt;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

public class DESUtils {

// 算法名称  
    private static final String KEY_ALGORITHM = "DES";  
    // 算法名称/加密模式/填充方式  
    private static final String CIPHER_ALGORITHM_ECB = "DES/ECB/PKCS5Padding";

    private static final Key defaultKey = generateKey();

    /**
     * 生成密钥
     */
    public static Key generateKey() {
    KeyGenerator keyGenerator;
try {
keyGenerator = KeyGenerator.getInstance(KEY_ALGORITHM);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Unable to generate DES key.", e);
}
    keyGenerator.init(56);//这里必须填56
    SecretKey secretKey = keyGenerator.generateKey();
    return secretKey;
    }

    /**
     * 使用默认密钥对字节数组进行加密，返回加密后的字节数组
     */
    public static byte[] encrypt(byte[] source) {
    return encrypt(source, null);
    }

    /**
     * 使用默认密钥对字节数组进行解密，返回解密后的字节数组
     */
    public static byte[] decrypt(byte[] source) {
    return decrypt(source, null);
    }

    /**
     * 使用指定密钥对字节数组进行加密，返回加密后的字节数组
     */
public static byte[] encrypt(byte[] source, Key key) {
try {
Key currentKey = key == null ? defaultKey : key;
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB);
cipher.init(Cipher.ENCRYPT_MODE, currentKey, new SecureRandom());  
        return cipher.doFinal(source);  
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Unable to encrypt.", e);
} catch (NoSuchPaddingException e) {
throw new RuntimeException("Unable to encrypt.", e);
} catch (InvalidKeyException e) {
throw new RuntimeException("Unable to encrypt.", e);
} catch (IllegalBlockSizeException e) {
throw new RuntimeException("Unable to encrypt.", e);
} catch (BadPaddingException e) {
throw new RuntimeException("Unable to encrypt.", e);
}  
}

 /**
     * 使用指定密钥对字节数组进行解密，返回解密后的字节数组
     */
public static byte[] decrypt(byte[] source, Key key) {
try {
Key currentKey = key == null ? defaultKey : key;
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB);
cipher.init(Cipher.DECRYPT_MODE, currentKey, new SecureRandom());  
        return cipher.doFinal(source);  
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Unable to decrypt.", e);
} catch (NoSuchPaddingException e) {
throw new RuntimeException("Unable to decrypt.", e);
} catch (InvalidKeyException e) {
throw new RuntimeException("Unable to decrypt.", e);
} catch (IllegalBlockSizeException e) {
throw new RuntimeException("Unable to decrypt.", e);
} catch (BadPaddingException e) {
throw new RuntimeException("Unable to decrypt.", e);
}  
}

public static void main(String[] args) {
String str = "测试字符串";
byte[] encrypted = DESUtils.encrypt(str.getBytes());

byte[] decrypted = DESUtils.decrypt(encrypted);
System.out.println("cipher text:" + new String(encrypted));
System.out.println("normal text:" + new String(decrypted));
}
}