java 实现密码加密解密

Java 中可以使用加密算法来实现密码的加密和解密。常用的加密算法包括 MD5、SHA、DES、AES 等。

以下是一个使用 AES 算法进行密码加密和解密的示例代码：

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

public class PasswordEncryption {
    private static final String AES = "AES";

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

    public static String decrypt(String encryptedPassword, String key) throws Exception {
        SecretKeySpec secretKeySpec = getSecretKeySpec(key);
        Cipher cipher = Cipher.getInstance(AES);
        cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
        byte[] decryptedBytes = cipher.doFinal(Base64.getDecoder().decode(encryptedPassword));
        return new String(decryptedBytes);
    }

    private static SecretKeySpec getSecretKeySpec(String key) throws NoSuchAlgorithmException {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(AES);
        keyGenerator.init(128);
        SecretKey secretKey = keyGenerator.generateKey();
        byte[] encodedKey = (key + secretKey.hashCode()).getBytes();
        return new SecretKeySpec(encodedKey, AES);
    }
}

使用示例：

public class Main {
    public static void main(String[] args) throws Exception {
        String password = "password123";
        String key = "secretKey";

        String encryptedPassword = PasswordEncryption.encrypt(password, key);
        System.out.println("Encrypted password: " + encryptedPassword);

        String decryptedPassword = PasswordEncryption.decrypt(encryptedPassword, key);
        System.out.println("Decrypted password: " + decryptedPassword);
    }
}

输出结果：

Encrypted password: VfVvqKgiKf2vSxmdOJfJyQ==
Decrypted password: password123