当前位置：首页 > Java

java 如何加密

2026-02-04 17:53:23Java

加密方法一：使用Java内置的MessageDigest类进行哈希加密

哈希加密适用于密码存储等场景，常见算法包括MD5、SHA-1、SHA-256等。以下示例展示SHA-256加密：

java 如何加密

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

public class HashExample {
    public static String encryptSHA256(String input) throws NoSuchAlgorithmException {
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        byte[] hash = digest.digest(input.getBytes());
        StringBuilder hexString = new StringBuilder();
        for (byte b : hash) {
            hexString.append(String.format("%02x", b));
        }
        return hexString.toString();
    }
}

加密方法二：使用对称加密（AES）

AES加密需要密钥，适用于数据加密传输或存储。以下是AES加密和解密的示例：

java 如何加密

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

public class AESExample {
    public static SecretKey generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
        keyGenerator.init(256); // 密钥长度
        return keyGenerator.generateKey();
    }

    public static String encrypt(String input, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedBytes = cipher.doFinal(input.getBytes());
        return Base64.getEncoder().encodeToString(encryptedBytes);
    }

    public static String decrypt(String encryptedInput, SecretKey key) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decodedBytes = Base64.getDecoder().decode(encryptedInput);
        byte[] decryptedBytes = cipher.doFinal(decodedBytes);
        return new String(decryptedBytes);
    }
}

加密方法三：使用非对称加密（RSA）

RSA适用于密钥交换或数字签名。以下是生成密钥对及加密解密的示例：

import javax.crypto.Cipher;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.util.Base64;

public class RSAExample {
    public static KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048); // 密钥长度
        return keyPairGenerator.generateKeyPair();
    }

    public static String encrypt(String input, java.security.PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] encryptedBytes = cipher.doFinal(input.getBytes());
        return Base64.getEncoder().encodeToString(encryptedBytes);
    }

    public static String decrypt(String encryptedInput, java.security.PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] decodedBytes = Base64.getDecoder().decode(encryptedInput);
        byte[] decryptedBytes = cipher.doFinal(decodedBytes);
        return new String(decryptedBytes);
    }
}

加密方法四：使用BCrypt进行密码哈希

BCrypt适合密码存储，自动加盐且抗彩虹表攻击。需引入依赖（如org.mindrot:jbcrypt）：

import org.mindrot.jbcrypt.BCrypt;

public class BCryptExample {
    public static String hashPassword(String plainTextPassword) {
        return BCrypt.hashpw(plainTextPassword, BCrypt.gensalt());
    }

    public static boolean checkPassword(String plainTextPassword, String hashedPassword) {
        return BCrypt.checkpw(plainTextPassword, hashedPassword);
    }
}