JAVA实现RSA加密解密 非对称算法

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首先RSA是一个非对称的加密算法，所以在使用该算法加密解密之前，必须先行生成密钥对，包括公钥和私钥

JDK中提供了生成密钥对的类KeyPairGenerator，实例如下：

public static Map<String, Object> genKeyPair() throws Exception {
		// 获取公钥私钥密钥对的生成器
		KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
		// 初始化确定密钥大小的密钥生成器
		kpg.initialize(1024);
		// 生成密钥对
		KeyPair kp = kpg.generateKeyPair();
		RSAPublicKey publicKey = (RSAPublicKey) kp.getPublic();
		RSAPrivateKey privateKey = (RSAPrivateKey) kp.getPrivate();
		Map<String, Object> keyMap = new HashMap<String, Object>();
		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);
		return keyMap;
	}

当你完成了密钥对的生成之后，你就可以将公钥公开出去了，让相关的加密程序通过该公钥对实施RSA加密

public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        //data即是待加密的数据String.getBytes即可
        byte[] keyBytes = Base64Utils.decode(publicKey);
        //根据指定的编码密钥创建一个新的X509EncodedKeySpec
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(ENCRYPT_ALGORITHM);
        //根据提供的密钥规范生成公钥对象
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        //用密钥初始化加密模式的cipher，所有后面的doFinal方法做的是加密
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {//一次加密的字节长度
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

加密完成之后通过自己的私钥对密文进行解密

public static byte[] decryptByPrivateKey(byte[] data, String privateKey)
			throws Exception {
		byte[] keyBytes = Base64Utils.decode(privateKey);
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(ENCRYPT_ALGORITHM);
		Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateK);
		int inputLen = data.length;
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		int offSet = 0;
		byte[] cache;
		int i = 0;
		// 对数据分段解密
		while (inputLen - offSet > 0) {
			if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
				cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
			} else {
				cache = cipher.doFinal(data, offSet, inputLen - offSet);
			}
			out.write(cache, 0, cache.length);
			i++;
			offSet = i * MAX_DECRYPT_BLOCK;
		}
		byte[] decryptedData = out.toByteArray();
		out.close();
		return decryptedData;
	}

try {
			Map<String, Object> keyMap = RSAUtils.genKeyPair();
			publicKey = RSAUtils.getPublicKey(keyMap);
			privateKey = RSAUtils.getPrivateKey(keyMap);
			System.out.println("公钥-->" + publicKey);
			System.out.println("私钥-->" + privateKey);
		} catch (Exception e) {
			e.printStackTrace();
		}

运行结果展示：

公钥-->MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCjJOdVRlDN/5nWHmpFtc9XffgmT2SAj7b+yBk55HSr1iQQt5k8/4O5qdnk3qxhgIgWuSyDpxR2FK5dzfXsomjc0L2CZGaStAkbbvw1wbOSYo11cxNpkphn3PIVbuBxrpEuCJ4HrMKTuBk662aA0ysxy2/BrK4NXxtRlMxI+/BYsQIDAQAB
私钥-->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

利用公钥加密，私钥解密：

System.out.println("公钥加密——私钥解密");
		System.out.println("加密前数据的内容是-->" + sourceStr);
		byte[] data = sourceStr.getBytes();
		byte[] encryptData = RSAUtils.encryptByPublicKey(data, publicKey);
		System.out.println("加密后的数据内容是-->" + new String(encryptData));
		byte[] decryptData = RSAUtils.decryptByPrivateKey(encryptData,
				privateKey);
		System.out.println("解密后的数据内容是-->" + new String(decryptData));

JAVA实现RSA加密解密 非对称算法,布布扣,bubuko.com

JAVA实现RSA加密解密 非对称算法

标签：blog   java   使用   os   io   数据   ar   2014   

原文地址：http://blog.csdn.net/simonchi/article/details/38580687