Android 安卓AES解密文件：BadPaddingException:EVP\u CipherFinal\u ex

我最近正在研究文件加密/解密

BadPaddingException:EVP_CipherFinal_ex:总是在我尝试使用相同密钥解密文件时发生

代码片段将发布在下面

我做错什么了吗

谢谢你的帮助

加密

public static void encryptFile() {
    File file = new File(Environment.getExternalStorageDirectory().getPath() + "/" + TARGET_FILE);

    FileInputStream fileInputStream;
    FileOutputStream fileOutputStream;

    byte[] buffer = new byte[1024 * 8];

    IvParameterSpec ivParameterSpec = new IvParameterSpec("1234567890123456".getBytes());

    byte[] key = "only for testing".getBytes();
    MessageDigest sha;
    try {
        sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    key = Arrays.copyOf(key, 16); // use only first 128 bit

    SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");

    try {
        fileInputStream = new FileInputStream(file);
        fileOutputStream = new FileOutputStream(Environment.getExternalStorageDirectory().getPath() + "/" + ENCRYPT_FILE);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);

        //CipherOutputStream cipherOutputStream = new CipherOutputStream(fileOutputStream, cipher);

        int read;

        while ((read = fileInputStream.read(buffer)) > 0) {
            Log.i(TAG, "encrypt read= " + read);

            byte[] encryptedData = cipher.doFinal(buffer);
            if (encryptedData != null) {
                Log.i(TAG, "encrypted size= " + encryptedData.length);
                fileOutputStream.write(encryptedData, 0, read);
            }

            //cipherOutputStream.write(buffer, 0, buffer.length);
        }
        //cipherOutputStream.flush();
        //cipherOutputStream.close();
        fileInputStream.close();
        fileOutputStream.close();

    } catch (IOException | NoSuchAlgorithmException | NoSuchPaddingException
            | IllegalBlockSizeException | BadPaddingException
            | InvalidAlgorithmParameterException | InvalidKeyException e) {
        e.printStackTrace();
    }
}

解密

public static void decryptFile() {
    File file = new File(Environment.getExternalStorageDirectory().getPath() + "/" + ENCRYPT_FILE);

    FileInputStream fileInputStream;
    FileOutputStream fileOutputStream;

    byte[] buffer = new byte[1024 * 8];

    IvParameterSpec ivParameterSpec = new IvParameterSpec("1234567890123456".getBytes());

    byte[] key = "only for testing".getBytes();
    MessageDigest sha;
    try {
        sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    key = Arrays.copyOf(key, 16); // use only first 128 bit

    SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");

    try {
        fileInputStream = new FileInputStream(file);
        fileOutputStream = new FileOutputStream(Environment.getExternalStorageDirectory().getPath() + "/" + DECRYPT_FILE);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);

        //CipherInputStream cipherInputStream = new CipherInputStream(fileInputStream, cipher);

        int read;

        while ((read = fileInputStream.read(buffer)) > 0) {
            Log.i(TAG, "decrypt read= " + read);

            byte[] decryptedData = cipher.doFinal(buffer);
            if (decryptedData != null) {
                Log.i(TAG, "decrypted size= " + decryptedData.length);
                fileOutputStream.write(decryptedData, 0, read);
            }

            //fileOutputStream.write(buffer, 0, buffer.length);
        }
        fileOutputStream.flush();
        fileOutputStream.close();
        //cipherInputStream.close();
        fileInputStream.close();

    } catch (IOException | NoSuchAlgorithmException | NoSuchPaddingException
            | IllegalBlockSizeException | BadPaddingException
            | InvalidAlgorithmParameterException | InvalidKeyException e) {
        e.printStackTrace();
    }
}

顺便说一句：当我使用CipherInputStream/CipherOutStream时，它会正常工作。我想知道是否可以只使用FileInputStream/FileOutputStream？多谢各位

编辑： 加密函数会将字节数组放大约16个字节，我已尝试增加解密的缓冲区大小，但仍然无法使其工作

byte[] buffer = new byte[1024 * 8 + 16];

日志：

I/##：解密读取=8208

javax.crypto.BadPaddingException:EVP\u CipherFinal\u ex

在com.android.org.conscrypt.NativeCrypto.EVP_CipherFinal_ex（本机方法）

访问com.android.org.conscrypt.OpenSSLCipher.doFinalInternal（OpenSSLCipher.java:430）

位于com.android.org.conscrypt.OpenSSLCipher.engineDoFinal（OpenSSLCipher.java:466）

位于javax.crypto.Cipher.doFinal（Cipher.java:1340）

位于CryptoHelper.decryptohelper文件（CryptoHelper.java:128）

编辑了根据#Robert的答案，为遇到与我相同问题的人更新代码

加密：

int read;

        while ((read = fileInputStream.read(buffer)) > 0) {
            Log.i(TAG, "encrypt read= " + read);
            byte[] encryptedData = cipher.update(buffer, 0, read);
            //byte[] encryptedData = cipher.doFinal(buffer);
            if (encryptedData != null) {
                Log.i(TAG, "encrypted size= " + encryptedData.length);
                fileOutputStream.write(encryptedData, 0, encryptedData.length);
            }

            //cipherOutputStream.write(buffer, 0, buffer.length);
        }
        byte[] finals = cipher.doFinal();
        Log.i(TAG, "encrypted finals = " + finals.length);
        fileOutputStream.write(finals, 0, finals.length);

解密：

int read;

        while ((read = fileInputStream.read(buffer)) > 0) {
            Log.i(TAG, "decrypt read= " + read);

            //byte[] decryptedData = cipher.doFinal(buffer);
            byte[] decryptedData = cipher.update(buffer, 0, read);
            if (decryptedData != null) {
                Log.i(TAG, "decrypted size= " + decryptedData.length);
                fileOutputStream.write(decryptedData, 0, decryptedData.length);
            }

            //fileOutputStream.write(buffer, 0, buffer.length);
        }
        byte[] finals = cipher.doFinal();
        Log.i(TAG, "decrypted finals = " + finals.length);
        fileOutputStream.write(finals, 0, finals.length);

---

再次感谢Robert的帮助。

您的问题是，您总是为每个错误的数据块调用

cipher.doFinal（）

，因为每个数据块都将被填充

如果您正在对数据块进行加密/解密，请使用

cipher.update（…）

并在处理最后一个数据块后只调用

cipher.doFinal（）

一次

---

更简单的方法是使用CipherInputStream/CipherOutputStream-它完全符合我为您描述的功能（关闭流时调用doFinal）。

您的问题是，您总是为每个错误的数据块调用

cipher.doFinal（）

，因为每个数据块都将被填充

如果您正在对数据块进行加密/解密，请使用

cipher.update（…）

并在处理最后一个数据块后只调用

cipher.doFinal（）

一次

---

更简单的方法是使用CipherInputStream/CipherOutputStream——它完全符合我为您描述的内容（关闭流时会调用doFinal）。

我按照您的答案编辑了代码。现在可以了。非常感谢你的帮助。你救了我一天。我按照你的答案编辑了代码。现在可以了。非常感谢你的帮助。你救了我一天。