Java 中基于 AES-256 密码的 Encryption/Decryption

AES-256 Password Based Encryption/Decryption in Java

我在 Java 中找到了实施 AES encryption/decryption 的指南,并在将其放入我自己的解决方案时尝试理解每一行。但是,我并不完全理解它,因此遇到了问题。最终目标是基于 encryption/decryption 的密码。我读过其他 articles/Whosebug 的帖子,但大多数都没有提供足够的解释(我在 Java 中对加密很陌生)

我现在的主要问题是即使我设置 byte[] saltBytes = "Hello".getBytes(); 最后我仍然得到不同的 Base64 结果(char[] password 每次都是随机的,但我读到以 char[] 形式保留密码更安全。我的另一个问题是当程序到达 decrypt(),我在 byte[] saltBytes = salt.getBytes("UTF-8");

提前谢谢你能给我的任何help/advice。

有问题的代码:

import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

public class EncryptionDecryption {

    private static String salt;
    private static int iterations = 65536  ;
    private static int keySize = 256;
    private static byte[] ivBytes;

    public static void main(String []args) throws Exception {

        char[] message = "PasswordToEncrypt".toCharArray();
        System.out.println("Message: " + message.toString());
        System.out.println("Encrypted: " + encrypt(message));
        System.out.println("Decrypted: " + decrypt(encrypt(message).toCharArray()));
    }

    public static String encrypt(char[] plaintext) throws Exception {

        salt = getSalt();
        byte[] saltBytes = salt.getBytes();

        SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
        SecretKey secretKey = skf.generateSecret(spec);
        SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
        AlgorithmParameters params = cipher.getParameters();
        ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
        byte[] encryptedTextBytes = cipher.doFinal(plaintext.toString().getBytes("UTF-8"));

        return DatatypeConverter.printBase64Binary(encryptedTextBytes);
    }

    public static String decrypt(char[] encryptedText) throws Exception {

        byte[] saltBytes = salt.getBytes("UTF-8");
        byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(encryptedText.toString());

        SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        PBEKeySpec spec = new PBEKeySpec(encryptedText, saltBytes, iterations, keySize);
        SecretKey secretkey = skf.generateSecret(spec);
        SecretKeySpec secretSpec = new SecretKeySpec(secretkey.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));

        byte[] decryptedTextBytes = null;

        try {
            decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
        }   catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        }   catch (BadPaddingException e) {
            e.printStackTrace();
        }

        return decryptedTextBytes.toString();

    }

    public static String getSalt() throws Exception {

        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
        byte[] salt = new byte[20];
        sr.nextBytes(salt);
        return salt.toString();
    }
}

我认为你犯了两个错误:)

我已经更正了您的示例代码以使其正常工作:

import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

public class EncryptionDecryption {

    private static String salt;
    private static int iterations = 65536  ;
    private static int keySize = 256;
    private static byte[] ivBytes;

    private static SecretKey secretKey;

    public static void main(String []args) throws Exception {

        salt = getSalt();

        char[] message = "PasswordToEncrypt".toCharArray();
        System.out.println("Message: " + String.valueOf(message));
        System.out.println("Encrypted: " + encrypt(message));
        System.out.println("Decrypted: " + decrypt(encrypt(message).toCharArray()));
    }

    public static String encrypt(char[] plaintext) throws Exception {
        byte[] saltBytes = salt.getBytes();

        SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
        secretKey = skf.generateSecret(spec);
        SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
        AlgorithmParameters params = cipher.getParameters();
        ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
        byte[] encryptedTextBytes = cipher.doFinal(String.valueOf(plaintext).getBytes("UTF-8"));

        return DatatypeConverter.printBase64Binary(encryptedTextBytes);
    }

    public static String decrypt(char[] encryptedText) throws Exception {

        System.out.println(encryptedText);

        byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(new String(encryptedText));
        SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));

        byte[] decryptedTextBytes = null;

        try {
            decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
        }   catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        }   catch (BadPaddingException e) {
            e.printStackTrace();
        }

        return new String(decryptedTextBytes);

    }

    public static String getSalt() throws Exception {

        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
        byte[] salt = new byte[20];
        sr.nextBytes(salt);
        return new String(salt);
    }
}

第一个错误是你生成了 2 个不同的盐(当使用加密方法时),所以 encrypted/decrypted 日志是不同的(逻辑上,但解密仍然有效,因为你在加密后直接调用解密).

第二个错误是密钥错误。您需要在加密时生成密钥,而不是解密。更简单地说,就好像我在用密码 "encrypt" 加密,而你试图用密码 "decrypt".

解密它

我建议您在启动时生成所有随机的东西(例如私钥、salt 等)。但请注意,当您停止应用程序时,除非获得完全相同的随机内容,否则您将无法解密旧内容。

希望我有所帮助:)

此致,