在Android上使用AES加密文件

Question

因此，我正在为自己开发一个个人项目，并且正在尝试加密手机上的文件。这些文件可以是任何文件，例如文档，照片等。现在，我正在尝试使其正常运行。每当我运行加密时，它似乎都可以正常工作并加密文件。当我运行解密时，有时它可以工作，而其他时候则不起作用。当它失败时，我通常会收到“在确定密码时出错，填充块已损坏”错误。我也没有使用不同的测试文件，所以它不像某些文件可以工作，而其他文件则不能。我每次都尝试相同的两个文件。

public static void encryptfile(String path,String Pass) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    FileInputStream fis = new FileInputStream(path);
    FileOutputStream fos = new FileOutputStream(path.concat(".crypt"));
    byte[] key = (salt + Pass).getBytes("UTF-8");
    MessageDigest sha = MessageDigest.getInstance("SHA-1");
    key = sha.digest(key);
    key = Arrays.copyOf(key,16);
    SecretKeySpec sks = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, sks);
    CipherOutputStream cos = new CipherOutputStream(fos, cipher);
    int b;
    byte[] d = new byte[8];
    while((b = fis.read(d)) != -1) {
        cos.write(d, 0, b);
    }
    cos.flush();
    cos.close();
    fis.close();
}

public static void decrypt(String path,String Pass) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    FileInputStream fis = new FileInputStream(path);
    FileOutputStream fos = new FileOutputStream(path.replace(".crypt",""));
    byte[] key = (salt + Pass).getBytes("UTF-8");
    MessageDigest sha = MessageDigest.getInstance("SHA-1");
    key = sha.digest(key);
    key = Arrays.copyOf(key,16);
    SecretKeySpec sks = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, sks);
    CipherInputStream cis = new CipherInputStream(fis, cipher);
    int b;
    byte[] d = new byte[8];
    while((b = cis.read(d)) != -1) {
        fos.write(d, 0, b);
    }
    fos.flush();
    fos.close();
    cis.close();
}

目前，Salt和密码是静态的，并且出于测试目的不会更改。仍然有大约一半的时间出错。

有谁知道为什么会这样吗？我一直在搜索，发现了一些可以尝试的方法，但都无济于事。
更新！

人们说得对，那是盐。当我除去盐时，问题就解决了……再多挖一点，原来是salt +
Pass是问题所在，但是因为salt是字节[]，而Pass是字符串。我将salt更改为String，然后使用salt.concat（Pass），问题解决了！

Answer 1

也许我缺少了一些东西，但就我而言，它可以正常工作。您能否仅通过更改fileToBeCrypted，fileToBeDecrypted和fileDecryptedOutput变量来尝试以下类？

package test;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

public class TestCrypt{

    private static final String salt = "t784";
    private static final String cryptPassword = "873147cbn9x5'2 79'79314";
    private static final String fileToBeCrypted = "c:\\Temp\\sampleFile.conf";
    private static final String fileToBeDecrypted = "c:\\Temp\\sampleFile.conf.crypt";
    private static final String fileDecryptedOutput = "c:\\Temp\\sampleFile.conf.decrypted";

    public static void main(String[] args) throws Exception
    {
        for (int i=0; i<100; i++)
        {
            encryptfile(fileToBeCrypted, cryptPassword);
            decrypt(fileToBeDecrypted, cryptPassword, fileDecryptedOutput);
            System.out.println(i);
        }
    }

    public static void encryptfile(String path,String password) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
        FileInputStream fis = new FileInputStream(path);
        FileOutputStream fos = new FileOutputStream(path.concat(".crypt"));
        byte[] key = (salt + password).getBytes("UTF-8");
        MessageDigest sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
        key = Arrays.copyOf(key,16);
        SecretKeySpec sks = new SecretKeySpec(key, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, sks);
        CipherOutputStream cos = new CipherOutputStream(fos, cipher);
        int b;
        byte[] d = new byte[8];
        while((b = fis.read(d)) != -1) {
            cos.write(d, 0, b);
        }
        cos.flush();
        cos.close();
        fis.close();
    }

    public static void decrypt(String path,String password, String outPath) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
        FileInputStream fis = new FileInputStream(path);
        FileOutputStream fos = new FileOutputStream(outPath);
        byte[] key = (salt + password).getBytes("UTF-8");
        MessageDigest sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
        key = Arrays.copyOf(key,16);
        SecretKeySpec sks = new SecretKeySpec(key, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, sks);
        CipherInputStream cis = new CipherInputStream(fis, cipher);
        int b;
        byte[] d = new byte[8];
        while((b = cis.read(d)) != -1) {
            fos.write(d, 0, b);
        }
        fos.flush();
        fos.close();
        cis.close();
    }

}

我可以多次迭代而不会出错！我正在使用Oracle JDK 1.8，但在1.7兼容模式下运行。

希望这可以帮助你。