问题：

使用AES加密和解密图像的正确方法

夏侯臻

2023-03-14

编辑：：：问题中的代码起作用，但一旦图像被相机拍摄，返回活动需要大约10秒的时间。我放弃了这种做法，使用Facebook的隐藏库来加密和解密图像。链接到Facebook的解决方案：Facebook隐藏-图像加密和解密

所以，我正在努力解决这个问题。我遵循下面的问题，正如SO上的大多数人所建议的那样（但这段代码展示了如何加密字符串）。有人能帮我加密和解密图像吗？问题中的代码是否适用于图像？

链接到问题：Java 256位AES基于密码的加密

以下是我到现在为止所做的：

//用于存储iv和密码的全局数组列表

static ArrayList<byte[]> ivandcipher = new ArrayList<byte[]>();

public static SecretKey generateKey() throws NoSuchAlgorithmException {

    char[] password = { 'a', 'b', 'c', 'd', 'e' };
    byte[] salt = { 1, 2, 3, 4, 5 };

    SecretKeyFactory factory = SecretKeyFactory
            .getInstance("PBKDF2WithHmacSHA1");
    KeySpec spec = new PBEKeySpec(password, salt, 65536, 256);
    SecretKey tmp = null;
    try {
        tmp = factory.generateSecret(spec);
    } catch (InvalidKeySpecException e) {
        e.printStackTrace();
    }

    yourKey = new SecretKeySpec(tmp.getEncoded(), "AES");

    return yourKey;
}

public static ArrayList<byte[]> encodeFile(SecretKey yourKey, byte[] fileData)
        throws Exception {

    byte[] encrypted = null;

    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, yourKey);
    AlgorithmParameters params = cipher.getParameters();
    byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
    encrypted = cipher.doFinal(fileData);   

    ivandcipher.clear();
    ivandcipher.add(iv);
    ivandcipher.add(encrypted);

    return ivandcipher;
}

private Bitmap decodeFile(String filename) {

    try {
        yourKey = generateKey();
    } catch (NoSuchAlgorithmException e1) {
        e1.printStackTrace();
    }

    try {
        byte[] decodedData = decodeFile(yourKey, readFile(filename));
        Bitmap bitmap = bytesToBitmap(decodedData);

        return bitmap;
    } catch (Exception e) {
        e.printStackTrace();
    }

    return null;
}

//重载decodeFile方法

public static byte[] decodeFile(SecretKey yourKey, byte[] fileData)
        throws Exception {

    byte[] decrypted = null;
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, yourKey, new IvParameterSpec(ivandcipher.get(0)));
    decrypted = cipher.doFinal(fileData);
    return decrypted;
}

我想问题出在FileData[]上，我无法正确加密和解密。对于上面链接的答案中所示的字符串，

byte[]ciphertext=cipher.doFinal（“Hello,World！”.GetBytes（“UTF-8”））；

龚睿

2023-03-14

可以使用Java库轻松地加密和解密图像。我向您展示两种不同的代码，使用两种不同的加密和解密方法。下面的代码也可以扩展到用于pdf文件。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.Key;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

public class ImageEncDec {

    public static byte[] getFile() {

        File f = new File("/home/bridgeit/Desktop/Olympics.jpg");
        InputStream is = null;
        try {
            is = new FileInputStream(f);
        } catch (FileNotFoundException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }
        byte[] content = null;
        try {
            content = new byte[is.available()];
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        try {
            is.read(content);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return content;
    }

    public static byte[] encryptPdfFile(Key key, byte[] content) {
        Cipher cipher;
        byte[] encrypted = null;
        try {
            cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            encrypted = cipher.doFinal(content);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return encrypted;

    }

    public static byte[] decryptPdfFile(Key key, byte[] textCryp) {
        Cipher cipher;
        byte[] decrypted = null;
        try {
            cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key);
            decrypted = cipher.doFinal(textCryp);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return decrypted;
    }

    public static void saveFile(byte[] bytes) throws IOException {

        FileOutputStream fos = new FileOutputStream("/home/bridgeit/Desktop/Olympics-new.jpg");
        fos.write(bytes);
        fos.close();

    }

    public static void main(String args[])
            throws NoSuchAlgorithmException, InstantiationException, IllegalAccessException, IOException {

        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
        keyGenerator.init(128);
        Key key = keyGenerator.generateKey();
        System.out.println(key);

        byte[] content = getFile();
        System.out.println(content);

        byte[] encrypted = encryptPdfFile(key, content);
        System.out.println(encrypted);

        byte[] decrypted = decryptPdfFile(key, encrypted);
        System.out.println(decrypted);

        saveFile(decrypted);
        System.out.println("Done");

    }

}

`这是第二个生成相同输出的代码，只是一次又一次地生成相同的密钥。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

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

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

public class Trial {

    public static byte[] getFile() {

        File f = new File("/home/bridgeit/Desktop/Olympics.jpg");
        InputStream is = null;
        try {
            is = new FileInputStream(f);
        } catch (FileNotFoundException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }
        byte[] content = null;
        try {
            content = new byte[is.available()];
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        try {
            is.read(content);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return content;
    }

    public static byte[] encryptPdfFile(SecretKey secretKey, byte[] content) {
        Cipher cipher;
        byte[] encrypted = null;
        try {
            cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");

            cipher.init(Cipher.ENCRYPT_MODE, secretKey);

            encrypted = Base64.encodeBase64(cipher.doFinal(content));

        } catch (Exception e) {

            System.out.println("Error while encrypting: " + e.toString());
        }
        return encrypted;

    }

    public static byte[] decryptPdfFile(SecretKey secretKey, byte[] textCryp) {
        Cipher cipher;
        byte[] decrypted = null;
        try {
            cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");

            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            decrypted = cipher.doFinal(Base64.decodeBase64(textCryp));

        } catch (Exception e) {

            System.out.println("Error while decrypting: " + e.toString());
        }
        return decrypted;
    }

    public static void saveFile(byte[] bytes) throws IOException {

        FileOutputStream fos = new FileOutputStream("/home/bridgeit/Desktop/Olympics-new.jpg");
        fos.write(bytes);
        fos.close();

    }

    public static void main(String args[])
            throws NoSuchAlgorithmException, InstantiationException, IllegalAccessException, IOException {

        SecretKeySpec secretKey;
        byte[] key;
        String myKey = "ThisIsAStrongPasswordForEncryptionAndDecryption";

        MessageDigest sha = null;
        key = myKey.getBytes("UTF-8");
        System.out.println(key.length);
        sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
        key = Arrays.copyOf(key, 16); // use only first 128 bit
        System.out.println(key.length);
        System.out.println(new String(key, "UTF-8"));
        secretKey = new SecretKeySpec(key, "AES");

        byte[] content = getFile();
        System.out.println(content);

        byte[] encrypted = encryptPdfFile(secretKey, content);
        System.out.println(encrypted);

        byte[] decrypted = decryptPdfFile(secretKey, encrypted);
        System.out.println(decrypted);

        saveFile(decrypted);
        System.out.println("Done");

    }

}

使用AES加密和解密图像的正确方法

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