Question

我已经使用了一些用于加密用户名和密码的代码并在文件中写入但是当我想要恢复这些值时，我没有得到原始值，我从文件中读取时会出现异常。我的代码是给出的。以下

public class Storage 
{
    private final byte[] salt = {
            ( byte )0xf5, ( byte )0x33, ( byte )0x01, ( byte )0x2a,
            ( byte )0xb2, ( byte )0xcc, ( byte )0xe4, ( byte )0x7f
            };
        private int iterationCount = 100;

        public void encryptAndWriteToFile(String host,String user,String pw,boolean flag)
        {
            String usr=host+","+user+","+pw+","+Boolean.toString(flag);
            Cipher cipher = null;
            try 
            {
                PBEKeySpec keySpec =new PBEKeySpec(usr.toCharArray());
                SecretKeyFactory keyFactory =SecretKeyFactory.getInstance( "PBEWithMD5AndDES" );
                SecretKey secretKey = keyFactory.generateSecret( keySpec );
                PBEParameterSpec parameterSpec =new PBEParameterSpec( salt, iterationCount );
                cipher = Cipher.getInstance( "PBEWithMD5AndDES" );
                cipher.init( Cipher.ENCRYPT_MODE, secretKey,parameterSpec );
            }catch ( NoSuchAlgorithmException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidKeySpecException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidKeyException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( NoSuchPaddingException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidAlgorithmParameterException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            byte[] outputArray = null;
            try 
            {
                outputArray = usr.getBytes( "ISO-8859-1" );
            }catch (UnsupportedEncodingException ex) 
            {
                        Logger.getLogger(Storage.class.getName()).log(Level.SEVERE, null, ex);
            }
            File sdCard=Environment.getExternalStorageDirectory();//+"/userData.txt";
            String user_credentails=sdCard.getName()+"/userData.txt";
            File file = new File(user_credentails);
            Log.d(user_credentails, "is input file ");
            FileOutputStream fileOutputStream = null;
            try
            {
                fileOutputStream = new FileOutputStream( file );
            }catch ( IOException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            CipherOutputStream out =new CipherOutputStream( fileOutputStream, cipher );
            try
            {
                out.write( outputArray );
                out.flush();
                out.close();
            }catch ( IOException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            Vector fileBytes = new Vector();
            try 
            {
                FileInputStream in = new FileInputStream( file );
                byte contents;
                while ( in.available() > 0 ) {
                contents = ( byte )in.read();
                fileBytes.add( new Byte( contents ) );
                }
                in.close();
            }catch ( IOException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            byte[] encryptedText = new byte[ fileBytes.size() ];
            for ( int i = 0; i < fileBytes.size(); i++ ) 
            {
                encryptedText[ i ] =
                ( ( Byte ) fileBytes.elementAt( i ) ).byteValue();
            }
        }
        public String[] readFromFileAndDecrypt(boolean state)
        {
            Vector fileBytes = new Vector();
            String pw = "123";
            String fileName = "security.txt";
            String usr="10.0.2.2"+","+"haider"+","+pw+","+Boolean.toString(state);
            Cipher cipher = null;
            try 
            {
                PBEKeySpec keySpec =new PBEKeySpec(usr.toCharArray());
                SecretKeyFactory keyFactory =SecretKeyFactory.getInstance( "PBEWithMD5AndDES" );
                SecretKey secretKey = keyFactory.generateSecret( keySpec );
                PBEParameterSpec parameterSpec =new PBEParameterSpec( salt, iterationCount );
                cipher = Cipher.getInstance( "PBEWithMD5AndDES" );

                cipher.init( Cipher.DECRYPT_MODE, secretKey,parameterSpec );
            }catch ( NoSuchAlgorithmException exception ) 
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidKeySpecException exception ) 
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidKeyException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( NoSuchPaddingException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }catch ( InvalidAlgorithmParameterException exception )
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            try 
            {
                File sdCard=Environment.getExternalStorageDirectory();
                String user_credentails=sdCard.getAbsolutePath()+"/userData.txt";
                Log.d(user_credentails, " is file name and path");
                File file = new File(user_credentails);
                FileInputStream fileInputStream =new FileInputStream( file );
                CipherInputStream in =new CipherInputStream( fileInputStream, cipher );
                byte contents = ( byte ) in.read();
                Log.d(Byte.toString(contents),"  is line");//.out.println("\n"+contents+"\n");
                while ( contents != -1 ) 
                {
                    fileBytes.add( new Byte( contents ) );
                    contents = ( byte ) in.read();
                }
                in.close();
            }catch ( IOException exception ) 
            {
                exception.printStackTrace();
                System.exit( 1 );
            }
            byte[] decryptedText = new byte[ fileBytes.size() ];
            for( int i = 0; i < fileBytes.size(); i++ ) 
            {
                 decryptedText[ i ] =( ( Byte )fileBytes.elementAt( i ) ).byteValue();
            }
            Log.d(new String(decryptedText)," is data");
            String uUser=new String( decryptedText );
            String[] delims=uUser.split(",");
            return delims;
        }

}

Answer 1

合理的方法是在首次启动应用程序时生成真正随机的AES密钥

See this

Answer 2

通常，如果您要存储帐户凭据，则应使用Android AccountManager：

http://developer.android.com/reference/android/accounts/AccountManager.html

如何在android中加密用户名和密码

2 个答案: