Java开发必须要掌握的加密方式(Java开发者必知的加密技术掌握指南)

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ithorizon 7个月前 (10-19) 阅读数 25 #后端开发

Java开发者必知的加密技术掌握指南

一、Java加密技术概述

在当今信息时代，数据平安显得尤为重要。Java作为一种广泛使用的编程语言，提供了多种加密技术来确保数据的平安。本文将详细介绍Java开发者必须掌握的加密对策，帮助大家更好地保护数据。

二、对称加密算法

对称加密算法是指加密和解密使用相同密钥的加密算法。以下是Java中常用的对称加密算法。

1. AES加密算法

AES（Advanced Encryption Standard）是一种高级加密标准，它使用128位、192位或256位的密钥进行加密。AES算法在Java中的实现如下：


import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;
public class AESUtil {
    private static final String ALGORITHM = "AES";
    public static SecretKey generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(128);
        return keyGenerator.generateKey();
    }
    public static String encrypt(String data, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }
    public static String decrypt(String encryptedData, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedData));
        return new String(decryptedData);
    }
}

2. DES加密算法

DES（Data Encryption Standard）是一种较早的对称加密算法，使用56位密钥进行加密。Java中的实现如下：


import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class DESUtil {
    private static final String ALGORITHM = "DES";
    public static SecretKey generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(56);
        return keyGenerator.generateKey();
    }
    public static String encrypt(String data, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }
    public static String decrypt(String encryptedData, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedData));
        return new String(decryptedData);
    }
}

3. 3DES加密算法

3DES（Triple Data Encryption Standard）是DES的改进版，使用三个密钥进行加密，强化了平安性。Java中的实现如下：


import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class TripleDESUtil {
    private static final String ALGORITHM = "DESede";
    public static SecretKey generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(112);
        return keyGenerator.generateKey();
    }
    public static String encrypt(String data, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }
    public static String decrypt(String encryptedData, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedData));
        return new String(decryptedData);
    }
}

三、非对称加密算法

非对称加密算法是指加密和解密使用不同密钥的加密算法，其中一个密钥是私钥，另一个是公钥。以下是Java中常用的非对称加密算法。

1. RSA加密算法

RSA是一种广泛使用的非对称加密算法，使用公钥加密和私钥解密，或者使用私钥加密和公钥解密。Java中的实现如下：


import java.security.*;
import java.util.Base64;
public class RSAUtil {
    private static final String ALGORITHM = "RSA";
    public static KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
        keyPairGenerator.initialize(2048);
        return keyPairGenerator.generateKeyPair();
    }
    public static String encrypt(String data, PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }
    public static String decrypt(String encryptedData, PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedData));
        return new String(decryptedData);
    }
}

2. ECC加密算法

ECC（Elliptic Curve Cryptography）是一种基于椭圆曲线的公钥加密算法，具有更高的平安性。Java中的实现如下：


import java.security.*;
import java.util.Base64;
public class ECCUtil {
    private static final String ALGORITHM = "EC";
    public static KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
        keyPairGenerator.initialize(256);
        return keyPairGenerator.generateKeyPair();
    }
    public static String encrypt(String data, PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }
    public static String decrypt(String encryptedData, PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedData));
        return new String(decryptedData);
    }
}

四、哈希算法

哈希算法是一种将任意长度的数据映射为固定长度的数据的算法，通常用于验证数据的完整性。以下是Java中常用的哈希算法。

1. MD5算法

MD5是一种广泛使用的哈希算法，输出长度为128位。Java中的实现如下：


import java.security.MessageDigest;
import java.util.Base64;
public class MD5Util {
    public static String hash(String data) throws Exception {
        MessageDigest messageDigest = MessageDigest.getInstance("MD5");
        byte[] hashedData = messageDigest.digest(data.getBytes());
        return Base64.getEncoder().encodeToString(hashedData);
    }
}

2. SHA算法

SHA（Secure Hash Algorithm）是一种更平安的哈希算法，包括SHA-1、SHA-256等。Java中的实现如下：


import java.security.MessageDigest;
import java.util.Base64;
public class SHAUtil {
    public static String hash(String data) throws Exception {
        MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
        byte[] hashedData = messageDigest.digest(data.getBytes());
        return Base64.getEncoder().encodeToString(hashedData);
    }
}

五、摘要认证

摘要认证是一种基于哈希算法的认证对策，常用于网络通信中的身份验证。以下是Java中实现摘要认证的示例。

1. HTTP摘要认证

HTTP摘要认证是一种基于HTTP协议的认证对策，使用哈希算法对用户名和密码进行加密。Java中的实现如下：


import java.security.MessageDigest;
import java.util.Base64;
public class HTTPDigestAuth {
    public static String generateResponse(String username, String realm, String password, String nonce, String cnonce, String qop, String uri) throws Exception {
        String ha1 = hash(username + ":" + realm + ":" + password);
        String ha2 = hash(qop + ":" + uri);
        String response = hash(ha1 + ":" + nonce + ":" + cnonce + ":" + qop + ":" + ha2);
        return response;
    }
    private static String hash(String data) throws Exception {
        MessageDigest messageDigest = MessageDigest.getInstance("MD5");
        byte[] hashedData = messageDigest.digest(data.getBytes());
        return Base64.getEncoder().encodeToString(hashedData);
    }
}