java - Android AES 加密/解密结果不正确

Question

我正在尝试在我的 Android 应用程序中进行 AES 加密/解密。我尝试过像 Encryption 这样的库, java-aes-crypto以及

中描述的实现

• Data Encryption and Decryption in Android ;
• Securely store user credentials (抛出最后一个字节异常)；
• AES Encryption Decryption in Android

无论我使用什么方法，解密部分都与原始数据不同。我总是得到这样的结果:

03-09 21:58:33.457 30329-30329/org.androidapp.test E/ERROR: BEFORE: sDuKOoRteaEUFtA3P0SllSTCpgKJN75FuyPLxdp/ctM=

03-09 21:58:33.459 30329-30329/org.androidapp.test E/ERROR: AFTER: PBSqM3jHZhemw48wd44pKg==

我现在正在做的一个简单例子:

    private static byte[] seedValue = {
        0x2d, 0x2a, 0x2d, 0x42, 0x55, 0x49, 0x4c, 0x44, 0x41, 0x43, 0x4f, 0x44, 0x45, 0x2d, 0x2a, 0x2d
};
private static String ALGORITHM = "AES";
private static SecretKeySpec secretKey = new SecretKeySpec(seedValue, "AES");


public static String encrypt( String data ) throws Exception {
    try {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] cipherText = cipher.doFinal(data.getBytes("UTF8"));
        String encryptedString = new String(Base64.encode(cipherText ,Base64.DEFAULT ) );
        return encryptedString;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

public static String decrypt(String data) throws Exception {
    try {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] cipherText = Base64.decode(data.getBytes("UTF8"), Base64.DEFAULT);
        String decryptedString = new String(cipher.doFinal(cipherText),"UTF-8");
        return decryptedString;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

使用这些方法的示例(使用 Jackson 来读取和写入对象):

public static void writeSecurityInfo( String fileName, POJO pojo ){
        try{
            FileUtil.verifyFile( fileName );
            ObjectMapper mapper = new ObjectMapper();

            File file = new File( Environment.getExternalStorageDirectory(), fileName );

            try {
                pojo.setName( CryptUtils.encrypt( pojo.getName() ) );
                pojo.setAddress( CryptUtils.encrypt( pojo.getAddress() ) );
            }
            catch( Exception e ){
                e.printStackTrace();
            }

            ObjectWriter writer = mapper.writer( new DefaultPrettyPrinter() );
            writer.writeValue( file, securityPOJO );
        }
        catch( IOException e ){
            e.printStackTrace();
        }
    }

供阅读:

public static POJO readSecurityInfo( String fileName ){
        try {
            File file = new File( Environment.getExternalStorageDirectory(), fileName );

            ObjectMapper mapper = new ObjectMapper();

            InputStream inputStream = new FileInputStream( file );

            POJO pojo = mapper.readValue( inputStream, POJO.class );
            Log.e("ERROR", "BEFORE: "+ pojo.getName());
            securityPOJO.setName( CryptUtils.decrypt( pojo.getName() ) );
            Log.e("ERROR", "AFTER: "+ pojo.getName());
            pojo.setAddress( CryptUtils.decrypt( pojo.getAddress() ) );

            return pojo;

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

没有成功。 使用 AES 时我做错了什么吗？

Answer 1

我没有发现您的加密和解密方法有任何错误。我用简单的文本测试了它:

try {
        String test = encrypt("My name is Nam");
        Log.e("TEST", "xxxx encrypted: "+ test);
        Log.e("TEST", "xxxx decrypted: "+ decrypt(test));
    } catch (Exception e) {
        e.printStackTrace();
    }

结果是正确的:

03-10 11:12:38.987 31251-31251/? E/TEST: xxxx encrypted: bR80WEK9pa3eicMjCZCtQg== 03-10 11:12:38.987 31251-31251/? E/TEST: xxxx decrypted: My name is Nam

所以，也许你写的日志不正确:

Log.e("ERROR", "AFTER: "+ pojo.getName());

应该是:

Log.e("ERROR", "AFTER: "+ securityPOJO.getName());

或

Log.e("ERROR", "AFTER: "+ CryptUtils.decrypt( pojo.getName() ));

注意:我编写了一个关于使用更安全的加密/解密的示例 in github如果你想检查的话。