简单的Java AES加密/解密示例

What's wrong with the following example?

以下示例有什么问题？

The problem is that the first part of the decrypted string is nonsense. However, the rest is fine, I get...

问题是解密字符串的第一部分是无意义的。但是，剩下的很好，我明白了......

Result: `£eB6O�geS��i are you? Have a nice day.

@Test
public void testEncrypt() {
  try {
    String s = "Hello there. How are you? Have a nice day.";

    // Generate key
    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    kgen.init(128);
    SecretKey aesKey = kgen.generateKey();

    // Encrypt cipher
    Cipher encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    encryptCipher.init(Cipher.ENCRYPT_MODE, aesKey);

    // Encrypt
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    CipherOutputStream cipherOutputStream = new CipherOutputStream(outputStream, encryptCipher);
    cipherOutputStream.write(s.getBytes());
    cipherOutputStream.flush();
    cipherOutputStream.close();
    byte[] encryptedBytes = outputStream.toByteArray();

    // Decrypt cipher
    Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    IvParameterSpec ivParameterSpec = new IvParameterSpec(aesKey.getEncoded());
    decryptCipher.init(Cipher.DECRYPT_MODE, aesKey, ivParameterSpec);

    // Decrypt
    outputStream = new ByteArrayOutputStream();
    ByteArrayInputStream inStream = new ByteArrayInputStream(encryptedBytes);
    CipherInputStream cipherInputStream = new CipherInputStream(inStream, decryptCipher);
    byte[] buf = new byte[1024];
    int bytesRead;
    while ((bytesRead = cipherInputStream.read(buf)) >= 0) {
        outputStream.write(buf, 0, bytesRead);
    }

    System.out.println("Result: " + new String(outputStream.toByteArray()));

  } 
  catch (Exception ex) {
    ex.printStackTrace();
  }
}

6 个解决方案

#1

Lot of people including myself face lot of issues in making this work due to missing some information like, forgetting to convert to Base64, initialization vectors, character set, etc. So I thought of making a fully functional code.

由于缺少一些信息，例如忘记转换为Base64，初始化向量，字符集等等，包括我自己在内的很多人在完成这项工作时面临很多问题。所以我想到制作一个功能齐全的代码。

Hope this will be useful to you all: To compile you need additional Apache Commons Codec jar, which is available here: http://commons.apache.org/proper/commons-codec/download_codec.cgi

希望这对大家都有用：要编译，你需要额外的Apache Commons Codec jar，可以在这里找到：http：//commons.apache.org/proper/commons-codec/download_codec.cgi

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

public class Encryptor {
    public static String encrypt(String key, String initVector, String value) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);

            byte[] encrypted = cipher.doFinal(value.getBytes());
            System.out.println("encrypted string: "
                    + Base64.encodeBase64String(encrypted));

            return Base64.encodeBase64String(encrypted);
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return null;
    }

    public static String decrypt(String key, String initVector, String encrypted) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);

            byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));

            return new String(original);
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return null;
    }

    public static void main(String[] args) {
        String key = "Bar12345Bar12345"; // 128 bit key
        String initVector = "RandomInitVector"; // 16 bytes IV

        System.out.println(decrypt(key, initVector,
                encrypt(key, initVector, "Hello World")));
    }
}

#2

Here a solution without Apache Commons Codec's Base64:

这里没有Apache Commons Codec的Base64的解决方案：

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public class AdvancedEncryptionStandard
{
    private byte[] key;

    private static final String ALGORITHM = "AES";

    public AdvancedEncryptionStandard(byte[] key)
    {
        this.key = key;
    }

    /**
     * Encrypts the given plain text
     *
     * @param plainText The plain text to encrypt
     */
    public byte[] encrypt(byte[] plainText) throws Exception
    {
        SecretKeySpec secretKey = new SecretKeySpec(key, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);

        return cipher.doFinal(plainText);
    }

    /**
     * Decrypts the given byte array
     *
     * @param cipherText The data to decrypt
     */
    public byte[] decrypt(byte[] cipherText) throws Exception
    {
        SecretKeySpec secretKey = new SecretKeySpec(key, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);

        return cipher.doFinal(cipherText);
    }
}

Usage example:

用法示例：

byte[] encryptionKey = "MZygpewJsCpRrfOr".getBytes(StandardCharsets.UTF_8);
byte[] plainText = "Hello world!".getBytes(StandardCharsets.UTF_8);
AdvancedEncryptionStandard advancedEncryptionStandard = new AdvancedEncryptionStandard(
        encryptionKey);
byte[] cipherText = advancedEncryptionStandard.encrypt(plainText);
byte[] decryptedCipherText = advancedEncryptionStandard.decrypt(cipherText);

System.out.println(new String(plainText));
System.out.println(new String(cipherText));
System.out.println(new String(decryptedCipherText));

Prints:

打印：

Hello world!
դ;��LA+�ߙb*
Hello world!

#3

Looks to me like you are not dealing properly with your Initialization Vector (IV). It's been a long time since I last read about AES, IVs and block chaining, but your line

在我看来，你没有正确处理初始化矢量（IV）。自从我上次阅读有关AES，IV和块链接以来，已经有很长一段时间了

IvParameterSpec ivParameterSpec = new IvParameterSpec(aesKey.getEncoded());

does not seem to be OK. In the case of AES, you can think of the initialization vector as the "initial state" of a cipher instance, and this state is a bit of information that you can not get from your key but from the actual computation of the encrypting cipher. (One could argue that if the IV could be extracted from the key, then it would be of no use, as the key is already given to the cipher instance during its init phase).

似乎不太好。在AES的情况下，您可以将初始化向量视为密码实例的“初始状态”，并且此状态是您无法从密钥获得的一些信息，而是来自加密密码的实际计算。 （有人可能会争辩说，如果IV可以从密钥中提取出来，那么它就没有用了，因为密钥已经在密钥实例的初始阶段给出了）。

Therefore, you should get the IV as a byte[] from the cipher instance at the end of your encryption

因此，您应该在加密结束时从密码实例获取IV作为byte []

  cipherOutputStream.close();
  byte[] iv = encryptCipher.getIV();

and you should initialize your Cipher in DECRYPT_MODE with this byte[] :

你应该使用这个byte []在DECRYPT_MODE中初始化你的密码：

  IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);

Then, your decryption should be OK. Hope this helps.

然后，你的解密应该没问题。希望这可以帮助。

#4

The IV that your using for decryption is incorrect. Replace this code

您用于解密的IV不正确。替换此代码

//Decrypt cipher
Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
IvParameterSpec ivParameterSpec = new IvParameterSpec(aesKey.getEncoded());
decryptCipher.init(Cipher.DECRYPT_MODE, aesKey, ivParameterSpec);

With this code

有了这段代码

//Decrypt cipher
Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
IvParameterSpec ivParameterSpec = new IvParameterSpec(encryptCipher.getIV());
decryptCipher.init(Cipher.DECRYPT_MODE, aesKey, ivParameterSpec);

And that should solve your problem.

这应该可以解决你的问题。

---

Below includes an example of a simple AES class in Java. I do not recommend using this class in production environments, as it may not account for all of the specific needs of your application.

下面包含Java中简单AES类的示例。我不建议在生产环境中使用此类，因为它可能无法满足应用程序的所有特定需求。

import java.nio.charset.StandardCharsets;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

public class AES 
{
    public static byte[] encrypt(final byte[] keyBytes, final byte[] ivBytes, final byte[] messageBytes) throws InvalidKeyException, InvalidAlgorithmParameterException
    {       
        return AES.transform(Cipher.ENCRYPT_MODE, keyBytes, ivBytes, messageBytes);
    }

    public static byte[] decrypt(final byte[] keyBytes, final byte[] ivBytes, final byte[] messageBytes) throws InvalidKeyException, InvalidAlgorithmParameterException
    {       
        return AES.transform(Cipher.DECRYPT_MODE, keyBytes, ivBytes, messageBytes);
    }

    private static byte[] transform(final int mode, final byte[] keyBytes, final byte[] ivBytes, final byte[] messageBytes) throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        final SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
        final IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
        byte[] transformedBytes = null;

        try
        {
            final Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding");

            cipher.init(mode, keySpec, ivSpec);

            transformedBytes = cipher.doFinal(messageBytes);
        }        
        catch (NoSuchAlgorithmException | NoSuchPaddingException | IllegalBlockSizeException | BadPaddingException e) 
        {
            e.printStackTrace();
        }
        return transformedBytes;
    }

    public static void main(final String[] args) throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        //Retrieved from a protected local file.
        //Do not hard-code and do not version control.
        final String base64Key = "ABEiM0RVZneImaq7zN3u/w==";

        //Retrieved from a protected database.
        //Do not hard-code and do not version control.
        final String shadowEntry = "AAECAwQFBgcICQoLDA0ODw==:ZtrkahwcMzTu7e/WuJ3AZmF09DE=";

        //Extract the iv and the ciphertext from the shadow entry.
        final String[] shadowData = shadowEntry.split(":");        
        final String base64Iv = shadowData[0];
        final String base64Ciphertext = shadowData[1];

        //Convert to raw bytes.
        final byte[] keyBytes = Base64.getDecoder().decode(base64Key);
        final byte[] ivBytes = Base64.getDecoder().decode(base64Iv);
        final byte[] encryptedBytes = Base64.getDecoder().decode(base64Ciphertext);

        //Decrypt data and do something with it.
        final byte[] decryptedBytes = AES.decrypt(keyBytes, ivBytes, encryptedBytes);

        //Use non-blocking SecureRandom implementation for the new IV.
        final SecureRandom secureRandom = new SecureRandom();

        //Generate a new IV.
        secureRandom.nextBytes(ivBytes);

        //At this point instead of printing to the screen, 
        //one should replace the old shadow entry with the new one.
        System.out.println("Old Shadow Entry      = " + shadowEntry);
        System.out.println("Decrytped Shadow Data = " + new String(decryptedBytes, StandardCharsets.UTF_8));
        System.out.println("New Shadow Entry      = " + Base64.getEncoder().encodeToString(ivBytes) + ":" + Base64.getEncoder().encodeToString(AES.encrypt(keyBytes, ivBytes, decryptedBytes)));
    }
}

Note that AES has nothing to do with encoding, which is why I chose to handle it separately and without the need of any third party libraries.

请注意，AES与编码无关，这就是我选择单独处理它而不需要任何第三方库的原因。

#5

It's often the good idea to rely on standard library provided solution:

依靠标准库提供的解决方案通常是个好主意：

private static void *15554296()
    throws
        NoSuchAlgorithmException, NoSuchPaddingException,        
        InvalidKeyException, IllegalBlockSizeException,
        BadPaddingException
{

    // prepare key
    KeyGenerator keygen = KeyGenerator.getInstance("AES");
    SecretKey aesKey = keygen.generateKey();
    String aesKeyForFutureUse = Base64.getEncoder().encodeToString(
            aesKey.getEncoded()
    );

    // cipher engine
    Cipher aesCipher = Cipher.getInstance("AES/ECB/PKCS5Padding");

    // cipher input
    aesCipher.init(Cipher.ENCRYPT_MODE, aesKey);
    byte[] clearTextBuff = "Text to encode".getBytes();
    byte[] cipherTextBuff = aesCipher.doFinal(clearTextBuff);

    // recreate key
    byte[] aesKeyBuff = Base64.getDecoder().decode(aesKeyForFutureUse);
    SecretKey aesDecryptKey = new SecretKeySpec(aesKeyBuff, "AES");

    // decipher input
    aesCipher.init(Cipher.DECRYPT_MODE, aesDecryptKey);
    byte[] decipheredBuff = aesCipher.doFinal(cipherTextBuff);
    System.out.println(new String(decipheredBuff));
}

This prints "Text to encode".

这将打印“要编码的文本”。

Solution is based on Java Cryptography Architecture Reference Guide and https://*.com/a/20591539/146745 answer.

解决方案基于Java Cryptography Architecture Reference Guide和https://*.com/a/20591539/146745 answer。

#6

Online Editor Runnable version:-

在线编辑器Runnable版本： -

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
//import org.apache.commons.codec.binary.Base64;
import java.util.Base64;

public class Encryptor {
    public static String encrypt(String key, String initVector, String value) {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));

            SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);

            byte[] encrypted = cipher.doFinal(value.getBytes());

            //System.out.println("encrypted string: "
              //      + Base64.encodeBase64String(encrypted));

            //return Base64.encodeBase64String(encrypted);
            String s = new String(Base64.getEncoder().encode(encrypted));
            return s;
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

    public static String decrypt(String key, String initVector, String encrypted) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);

            byte[] original = cipher.doFinal(Base64.getDecoder().decode(encrypted));

            return new String(original);
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return null;
    }

    public static void main(String[] args) {
        String key = "Bar12345Bar12345"; // 128 bit key
        String initVector = "RandomInitVector"; // 16 bytes IV

        System.out.println(encrypt(key, initVector, "Hello World"));
        System.out.println(decrypt(key, initVector, encrypt(key, initVector, "Hello World")));
    }
}