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Java常用加密算法詳解與示例代碼

更新時(shí)間：2025年07月09日 09:52:10 作者：Micro麥可樂(lè)

在信息安全領(lǐng)域,加密算法是保護(hù)數(shù)據(jù)機(jī)密性、完整性和身份認(rèn)證的核心手段,Java 標(biāo)準(zhǔn)庫(kù)及第三方框架提供了豐富的加解密實(shí)現(xiàn),本文將結(jié)合 Java 代碼,詳細(xì)介紹常用的幾類加密算法,并給出可直接運(yùn)行的測(cè)試示例,幫助小伙伴們快速上手,需要的朋友可以參考下

1. 前言

在信息安全領(lǐng)域，加密算法是保護(hù)數(shù)據(jù)機(jī)密性、完整性和身份認(rèn)證的核心手段。Java 標(biāo)準(zhǔn)庫(kù)及第三方框架（如 BouncyCastle）提供了豐富的加解密實(shí)現(xiàn)，這里小編將結(jié)合 Java 代碼，詳細(xì)介紹常用的幾類加密算法，并給出可直接運(yùn)行的測(cè)試示例，幫助小伙伴們快速上手。

2. 加密算法基礎(chǔ)分類

2.1 哈希算法

特點(diǎn)：?jiǎn)蜗虿豢赡妫潭ㄩL(zhǎng)度輸出
用途：數(shù)據(jù)完整性驗(yàn)證、密碼存儲(chǔ)
代表算法：MD5、SHA-1、SHA-256、SHA-512

2.2 對(duì)稱加密算法

特點(diǎn)：加密解密使用相同密鑰
優(yōu)勢(shì)：速度快，適合大數(shù)據(jù)量加密
代表算法：AES、DES、3DES、RC4

2.3 非對(duì)稱加密算法

特點(diǎn)：公鑰加密，私鑰解密
優(yōu)勢(shì)：安全性高，解決密鑰分發(fā)問(wèn)題
代表算法：RSA、ECC、DSA

2.4 消息認(rèn)證碼（MAC）

特點(diǎn)：帶密鑰的哈希函數(shù)
用途：驗(yàn)證消息完整性和來(lái)源
代表算法：HMAC

3. 哈希算法

3.1 原理與特點(diǎn)

Hash（摘要）：將任意長(zhǎng)度的數(shù)據(jù)“壓縮”成定長(zhǎng)的輸出，常用于數(shù)據(jù)完整性校驗(yàn)。
不可逆：無(wú)法從摘要反向推算原文；對(duì)抗碰撞攻擊（不同輸入產(chǎn)生相同輸出）是設(shè)計(jì)目標(biāo)之一。

3.2 Java 示例

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class HashUtils {

    public static String hash(String input, String algorithm) {
        try {
            MessageDigest md = MessageDigest.getInstance(algorithm);
            byte[] digest = md.digest(input.getBytes());
            // 轉(zhuǎn)為十六進(jìn)制
            StringBuilder sb = new StringBuilder();
            for (byte b : digest) {
                sb.append(String.format("%02x", b & 0xff));
            }
            return sb.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("Unknown algorithm: " + algorithm, e);
        }
    }

    // 測(cè)試主函數(shù)
    public static void main(String[] args) {
        String text = "HelloWorld";
        System.out.println("MD5:    " + hash(text, "MD5"));
        System.out.println("SHA-1:  " + hash(text, "SHA-1"));
        System.out.println("SHA-256:" + hash(text, "SHA-256"));
    }
}

運(yùn)行后，你將看到三種摘要值，驗(yàn)證不同算法的輸出長(zhǎng)度和差異。

4. 對(duì)稱加密算法

對(duì)稱加密使用同一個(gè)密鑰進(jìn)行加解密，速度快，適合大數(shù)據(jù)量場(chǎng)景。

由于 DES 已較為過(guò)時(shí)，不推薦在新項(xiàng)目中使用，這里就不做DES介紹了，下面主要講解一下AES

2.1 AES（Advanced Encryption Standard）

密鑰長(zhǎng)度：128/192/256 位
模式：ECB（電子密碼本）、CBC（密碼分組鏈接）等；CBC 更安全但需 IV

2.2 AES 示例

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import java.util.Base64;

public class AESUtils {

    // 生成 AES 密鑰
    public static SecretKey genKey(int keySize) throws Exception {
        KeyGenerator kg = KeyGenerator.getInstance("AES");
        kg.init(keySize);
        return kg.generateKey();
    }

    // 加密
    public static String encrypt(String plaintext, SecretKey key, IvParameterSpec iv) throws Exception {
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, iv);
        byte[] encrypted = cipher.doFinal(plaintext.getBytes());
        return Base64.getEncoder().encodeToString(encrypted);
    }

    // 解密
    public static String decrypt(String ciphertext, SecretKey key, IvParameterSpec iv) throws Exception {
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, key, iv);
        byte[] decoded = Base64.getDecoder().decode(ciphertext);
        byte[] decrypted = cipher.doFinal(decoded);
        return new String(decrypted);
    }

    public static void main(String[] args) throws Exception {
        String text = "SecretMessage";
        SecretKey key = genKey(128);
        // 隨機(jī) IV，也可使用固定 IV（不推薦）
        byte[] ivBytes = new byte[16];
        System.arraycopy("RandomInitVector".getBytes(), 0, ivBytes, 0, 16);
        IvParameterSpec iv = new IvParameterSpec(ivBytes);

        String cipherText = encrypt(text, key, iv);
        String plainText = decrypt(cipherText, key, iv);

        System.out.println("原文: " + text);
        System.out.println("加密: " + cipherText);
        System.out.println("解密: " + plainText);
    }
}

5. 非對(duì)稱加密算法

5.1 RSA算法

算法特點(diǎn)：

基于大數(shù)分解難題
密鑰長(zhǎng)度：1024-4096位
用途：數(shù)字簽名、密鑰交換

import javax.crypto.Cipher;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class RSAExample {
    public static void main(String[] args) throws Exception {
        String plainText = "Java非對(duì)稱加密算法";
        
        // 生成密鑰對(duì)
        KeyPair keyPair = generateRSAKeyPair();
        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();
        
        // 公鑰加密
        byte[] cipherText = encryptRSA(plainText, publicKey);
        System.out.println("RSA加密結(jié)果: " + Base64.getEncoder().encodeToString(cipherText));
        
        // 私鑰解密
        String decryptedText = decryptRSA(cipherText, privateKey);
        System.out.println("RSA解密結(jié)果: " + decryptedText);
        
        // 數(shù)字簽名示例
        byte[] signature = signData(plainText, privateKey);
        boolean isValid = verifySignature(plainText, signature, publicKey);
        System.out.println("簽名驗(yàn)證結(jié)果: " + isValid);
    }

    public static KeyPair generateRSAKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048); // 密鑰長(zhǎng)度
        return keyPairGenerator.generateKeyPair();
    }

    public static byte[] encryptRSA(String plainText, PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
    }

    public static String decryptRSA(byte[] cipherText, PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] decryptedBytes = cipher.doFinal(cipherText);
        return new String(decryptedBytes, StandardCharsets.UTF_8);
    }

    public static byte[] signData(String data, PrivateKey privateKey) throws Exception {
        Signature signature = Signature.getInstance("SHA256withRSA");
        signature.initSign(privateKey);
        signature.update(data.getBytes(StandardCharsets.UTF_8));
        return signature.sign();
    }

    public static boolean verifySignature(String data, byte[] signatureBytes, PublicKey publicKey) throws Exception {
        Signature signature = Signature.getInstance("SHA256withRSA");
        signature.initVerify(publicKey);
        signature.update(data.getBytes(StandardCharsets.UTF_8));
        return signature.verify(signatureBytes);
    }
}

5.2 ECC（橢圓曲線加密）

算法特點(diǎn)：

同等安全強(qiáng)度下密鑰更短
計(jì)算效率高
適合移動(dòng)設(shè)備

import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class ECCExample {
    public static void main(String[] args) throws Exception {
        String plainText = "Java橢圓曲線加密";
        
        // 生成密鑰對(duì)
        KeyPair keyPair = generateECCKeyPair();
        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();
        
        // 密鑰序列化/反序列化演示
        String pubKeyStr = Base64.getEncoder().encodeToString(publicKey.getEncoded());
        String priKeyStr = Base64.getEncoder().encodeToString(privateKey.getEncoded());
        
        // 從字符串恢復(fù)密鑰
        PublicKey restoredPubKey = restoreECCPublicKey(pubKeyStr);
        PrivateKey restoredPriKey = restoreECCPrivateKey(priKeyStr);
        
        // 數(shù)字簽名
        byte[] signature = signDataECC(plainText, restoredPriKey);
        boolean isValid = verifySignatureECC(plainText, signature, restoredPubKey);
        System.out.println("ECC簽名驗(yàn)證結(jié)果: " + isValid);
    }

    public static KeyPair generateECCKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC");
        keyPairGenerator.initialize(256); // 密鑰長(zhǎng)度
        return keyPairGenerator.generateKeyPair();
    }

    public static PublicKey restoreECCPublicKey(String keyStr) throws Exception {
        byte[] keyBytes = Base64.getDecoder().decode(keyStr);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("EC");
        return keyFactory.generatePublic(keySpec);
    }

    public static PrivateKey restoreECCPrivateKey(String keyStr) throws Exception {
        byte[] keyBytes = Base64.getDecoder().decode(keyStr);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("EC");
        return keyFactory.generatePrivate(keySpec);
    }

    public static byte[] signDataECC(String data, PrivateKey privateKey) throws Exception {
        Signature signature = Signature.getInstance("SHA256withECDSA");
        signature.initSign(privateKey);
        signature.update(data.getBytes(StandardCharsets.UTF_8));
        return signature.sign();
    }

    public static boolean verifySignatureECC(String data, byte[] signatureBytes, PublicKey publicKey) throws Exception {
        Signature signature = Signature.getInstance("SHA256withECDSA");
        signature.initVerify(publicKey);
        signature.update(data.getBytes(StandardCharsets.UTF_8));
        return signature.verify(signatureBytes);
    }
}

6. 消息認(rèn)證碼（HMAC）

HMAC 用于驗(yàn)證數(shù)據(jù)完整性及認(rèn)證，結(jié)合了 Hash 與密鑰。

算法特點(diǎn)：

輸入：密鑰 + 消息 → 通過(guò) Hash 計(jì)算，輸出固定長(zhǎng)度摘要。
常見(jiàn)算法：HmacMD5、HmacSHA1、HmacSHA256

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

public class HMACExample {
    public static void main(String[] args) throws Exception {
        String message = "重要業(yè)務(wù)數(shù)據(jù)";
        String secretKey = "MySecretKey123";
        
        // 計(jì)算HMAC
        String hmac = calculateHMAC(message, secretKey);
        System.out.println("HMAC-SHA256: " + hmac);
        
        // 驗(yàn)證消息完整性
        String receivedMessage = "重要業(yè)務(wù)數(shù)據(jù)";
        String receivedHmac = calculateHMAC(receivedMessage, secretKey);
        System.out.println("HMAC驗(yàn)證結(jié)果: " + hmac.equals(receivedHmac));
    }

    public static String calculateHMAC(String data, String key) 
            throws NoSuchAlgorithmException, InvalidKeyException {
        Mac sha256Hmac = Mac.getInstance("HmacSHA256");
        SecretKeySpec secretKey = new SecretKeySpec(
            key.getBytes(StandardCharsets.UTF_8), 
            "HmacSHA256"
        );
        sha256Hmac.init(secretKey);
        byte[] hmacBytes = sha256Hmac.doFinal(data.getBytes(StandardCharsets.UTF_8));
        return Base64.getEncoder().encodeToString(hmacBytes);
    }
}