JAVA中為我們提供了豐富的加密技術。能夠主要的分為單向加密和非對稱加密

1.單向加密算法

單向加密算法主要用來驗證傳輸數據的過程中。是否被篡改過。

• BASE64 嚴格地說，屬於編碼格式。而非加密算法

• MD5(Message Digest algorithm 5，信息摘要算法)

• SHA(Secure Hash Algorithm。安全散列算法)

• HMAC(Hash Message Authentication Code，散列消息鑒別碼

• DES(Data Encryption Standard，數據加密算法)

• PBE(Password-based encryption，基於password驗證)

• RSA(算法的名字以發明者的名字命名：Ron Rivest, AdiShamir 和Leonard Adleman)

• DH(Diffie-Hellman算法。密鑰一致協議)

• DSA(Digital Signature Algorithm。數字簽名)

• ECC(Elliptic Curves Cryptography，橢圓曲線password編碼學)

• 
  

package com.test;
import java.security.MessageDigest;

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

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**  
 * @ClassName: coder   
 * @Description: 加密組件
 * @author: LUCKY  
 * @date:2016年1月4日 下午1:24:12     
 */ 
public abstract class coder {
    public static final String KEY_SHA = "SHA";
    public static final String KEY_MD5 = "MD5";
 
    /**
     * MAC算法可選以下多種算法
     * 
     * <pre>
     * HmacMD5 
     * HmacSHA1 
     * HmacSHA256 
     * HmacSHA384 
     * HmacSHA512
     * </pre>
     */
    public static final String KEY_MAC = "HmacMD5";
 
    /**
     * BASE64解密
     * 
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptBASE64(String key) throws Exception {
        return (new BASE64Decoder()).decodeBuffer(key);
    }
 
    /**
     * BASE64加密
     * 
     * @param key
     * @return
     * @throws Exception
     */
    public static String encryptBASE64(byte[] key) throws Exception {
        return (new BASE64Encoder()).encodeBuffer(key);
    }
 
    /**
     * MD5加密
     * 
     * @param data
     * @return
     * @throws Exception
     */
    public static byte[] encryptMD5(byte[] data) throws Exception {
 
        MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);
        md5.update(data);
 
        return md5.digest();
 
    }
 
    /**
     * SHA加密
     * 
     * @param data
     * @return
     * @throws Exception
     */
    public static byte[] encryptSHA(byte[] data) throws Exception {
 
        MessageDigest sha = MessageDigest.getInstance(KEY_SHA);
        sha.update(data);
 
        return sha.digest();
 
    }
 
    /**
     * 初始化HMAC密鑰
     * 
     * @return
     * @throws Exception
     */
    public static String initMacKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);
 
        SecretKey secretKey = keyGenerator.generateKey();
        
        return encryptBASE64(secretKey.getEncoded());
    }
 
    /**
     * HMAC加密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptHMAC(byte[] data, String key) throws Exception {
 
        SecretKey secretKey = new SecretKeySpec(decryptBASE64(key), KEY_MAC);
        Mac mac = Mac.getInstance(secretKey.getAlgorithm());
        mac.init(secretKey);
 
        return mac.doFinal(data);
 
    }
}
 

package com.test;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;
 

/**  
 * @ClassName: RSACoder   
 * @Description: RSA安全編碼組件
 * @author: LUCKY  
 * @date:2016年1月4日 下午1:25:34     
 */ 
public abstract class RSACoder extends coder {
    public static final String KEY_ALGORITHM = "RSA";
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
 
    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";
 
    /**
     * 用私鑰對信息生成數字簽名
     * 
     * @param data
     *            加密數據
     * @param privateKey
     *            私鑰
     * 
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        // 解密由base64編碼的私鑰
        byte[] keyBytes = decryptBASE64(privateKey);
 
        // 構造PKCS8EncodedKeySpec對象
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
 
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
 
        // 取私鑰匙對象
        PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
 
        // 用私鑰對信息生成數字簽名
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(priKey);
        signature.update(data);
 
        return encryptBASE64(signature.sign());
    }
 
    /**
     * 校驗數字簽名
     * 
     * @param data
     *            加密數據
     * @param publicKey
     *            公鑰
     * @param sign
     *            數字簽名
     * 
     * @return 校驗成功返回true 失敗返回false
     * @throws Exception
     * 
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
 
        // 解密由base64編碼的公鑰
        byte[] keyBytes = decryptBASE64(publicKey);
 
        // 構造X509EncodedKeySpec對象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
 
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
 
        // 取公鑰匙對象
        PublicKey pubKey = keyFactory.generatePublic(keySpec);
 
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(pubKey);
        signature.update(data);
 
        // 驗證簽名是否正常
        return signature.verify(decryptBASE64(sign));
    }
 
    /**
     * 解密<br>
     * 用私鑰解密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] data, String key)
            throws Exception {
        // 對密鑰解密
        byte[] keyBytes = decryptBASE64(key);
 
        // 取得私鑰
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
 
        // 對數據解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
 
        return cipher.doFinal(data);
    }
 
    /**
     * 解密<br>
     * 用私鑰解密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] data, String key)
            throws Exception {
        // 對密鑰解密
        byte[] keyBytes = decryptBASE64(key);
 
        // 取得公鑰
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
 
        // 對數據解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
 
        return cipher.doFinal(data);
    }
 
    /**
     * 加密<br>
     * 用公鑰加密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String key)
            throws Exception {
        // 對公鑰解密
        byte[] keyBytes = decryptBASE64(key);
 
        // 取得公鑰
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
 
        // 對數據加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
 
        return cipher.doFinal(data);
    }
 
    /**
     * 加密<br>
     * 用私鑰加密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String key)
            throws Exception {
        // 對密鑰解密
        byte[] keyBytes = decryptBASE64(key);
 
        // 取得私鑰
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
 
        // 對數據加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
 
        return cipher.doFinal(data);
    }
 
    /**
     * 取得私鑰
     * 
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
 
        return encryptBASE64(key.getEncoded());
    }
 
    /**
     * 取得公鑰
     * 
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
 
        return encryptBASE64(key.getEncoded());
    }
 
    /**
     * 初始化密鑰
     * 
     * @return
     * @throws Exception
     */
    public static Map<String, Object> initKey() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator
                .getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
 
        KeyPair keyPair = keyPairGen.generateKeyPair();
 
        // 公鑰
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
 
        // 私鑰
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
 
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
 
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }
}
 

Java中的各種加密算法