Encrypt in php and decrypt in Dart(flutter) about encrypt

[HimanshuSaikia]

Bro, checkout encryptBytes and decryptBytes: https://pub.dev/documentation/encrypt/latest/encrypt/Encrypter/encryptBytes.html ;)

BRO, YOU ARE AMAZING. Thank you so much for the much needed support. I owe you.
Finally I did the php encryption and dart decryption successfully for a video file.
There was a slight trick though, and that was, openssl_encrypt() does a base64 encoding to the final output which is then saved to the file. So, in dart, before passing to decryptBytes we need to do a base64 decoding first for the string in the encrypted file. I am providing my code open here. Thanks once again Leo Cavalcante.

PHP Encryption code
I am using the following key and iv in php.
$key='FCAcEA0HBAoRGyALBQIeCAcaDxYWEQQPBxcXHgAFDgY=';
$iv='DB4gHxkcBQkKCxoRGBkaFA==';

The encryption& decryption functions:

function encryptFile($encKey, $encIV, $inPath, $outPath) {
        $sourceFile=file_get_contents($inPath);
        $key = base64_decode($encKey);
        $iv = base64_decode($encIV);
        $path_parts = pathinfo($inPath);
        $fileName=$path_parts['filename'];
        $outFile=$outPath.$fileName.'.himu';
        $encrypter = 'aes-256-cbc';
        $encryptedString = openssl_encrypt($sourceFile, $encrypter, $key, 0, $iv);
        if(file_put_contents($outFile, $encryptedString)!= false) return 1;
        else return 0;
    }

PHP Decryption

function decryptFile($encKey, $encIV, $inPath, $outPath) {
        $encryptedString=file_get_contents($inPath);
        $key = base64_decode($encKey);
        $iv = base64_decode($encIV);
	$path_parts = pathinfo($inPath);
        $fileName=$path_parts['filename'];
        $outFile=$outPath.$fileName.'.mp4';
        $encrypter = 'aes-256-cbc';
        $decrypted = openssl_decrypt($encryptedString, $encrypter, $key, 0, $iv);
        if(file_put_contents($outFile, $decrypted)!= false) return 1;
        else return 0;
    }

DART Decryption
import 'package:encrypt/encrypt.dart' as enc;
import 'package:path/path.dart' as p;
import 'dart:async';
import 'dart:io';

Future<String> decryptFile(filePath) async{  //'filePath' contains the php encrypted video file.
    var encodedKey = 'FCAcEA0HBAoRGyALBQIeCAcaDxYWEQQPBxcXHgAFDgY=';
    var encodedIv = 'DB4gHxkcBQkKCxoRGBkaFA==';
    var encryptedBase64EncodedString = new File(filePath).readAsStringSync();
    var decoded = base64.decode(encryptedBase64EncodedString);
    final key1 = enc.Key.fromBase64(encodedKey);
    final iv = enc.IV.fromBase64(encodedIv);
    final encrypter = enc.Encrypter(enc.AES(key1, mode: enc.AESMode.cbc));
    final decrypted = encrypter.decryptBytes(enc.Encrypted(decoded), iv: iv);
    final filename = '${p.basenameWithoutExtension(filePath)}.mp4';
    final directoryName=p.dirname(filePath);
    final newFilePath=p.join(directoryName, filename);
    var newFile = new File(newFilePath);
    await newFile.writeAsBytes(decrypted);
    return newFilePath;
  }

[leocavalcante]

Hi @mmojbo
Is your decrypted string {"opr":1}?
Try:

final key = Key.fromUtf8('&5P483usHDhA32JUj55@CdcrbupasysB');
final encrypter = Encrypter(AES(key, mode: AESMode.cbc));
print(encrypter.decrypt64('k2EfYozdaJudTbKjPj2WmQ==', iv: IV.fromLength(16)));

[mmojbo]

can anyone help me?
@yapcwed @shutup @Jethro87 @benittopremkumar @hasimyerlikaya

[mmojbo]

Thank you so much, Leo, it's working!

[joumduk]

Can you share how to encrypt data in php ?

[leocavalcante]

@joumduk see if this helps #87 (comment)

[HimanshuSaikia]

Please help/guide me to decrypt an encrypted mp4 file in dart. The file was encrypted using PHP OpenSSL encrypt with AES-256-CBC mode.

[leocavalcante]

Hi @HimanshuSaikia, it will be like in #87 (comment) but instead of using a argument from the command line input, you should use Dart's IO File reader.

[sandeepsoni25]

how can i encrypt/decrypt my pdf file?

[leocavalcante]

@sandeepsoni25 load the file as bytes and use encrypt bytes.

[HimanshuSaikia]

Hi @HimanshuSaikia, it will be like in #87 (comment) but instead of using a argument from the command line input, you should use Dart's IO File reader.

Thanks a lot for your instant reply. So, according to your logic, I successfully encrypted a file in php, decrypted the file in php too. Although text decryption is working in dart, But when i try to decrypt a video file in dart, it's not working. The output file is not recognised as any format by the player. also the file size is larger than the original as well as the encrypted file.
The source mp4 file was 253kb
The encrypted file was 337kb
The dart decrypted mp4 file was 448 kb and not read by the player
PHP decryption is working fine and generates a 253kb mp4 file.
Simple text decryption in Dart and output to a text file is working fine.

I kept same Key as yours
I kept same IV as yours

My decryption code is:
//***********************
import 'package:encrypt/encrypt.dart' as enc;
import 'package:path/path.dart' as p;
import 'dart:async';
import 'dart:io';
//**********************

Future<String> decryptFile(filePath) async{  //'filePath' contains the php encrypted video file.
    var encodedKey = 'FCAcEA0HBAoRGyALBQIeCAcaDxYWEQQPBxcXHgAFDgY=';
    var encodedIv = 'DB4gHxkcBQkKCxoRGBkaFA==';
    var text = new File(filePath).readAsStringSync();
    final key1 = enc.Key.fromBase64(encodedKey);
    final iv = enc.IV.fromBase64(encodedIv);
    final encrypter = enc.Encrypter(enc.AES(key1, mode: enc.AESMode.cbc));
    final decrypted = encrypter.decrypt(enc.Encrypted.fromBase64(text), iv: iv);
    final filename = '${p.basenameWithoutExtension(filePath)}.mp4';
    final directoryName=p.dirname(filePath);
    final newFilePath=p.join(directoryName, filename);
    List<int> bytes = utf8.encode(decrypted);print(bytes);
    var newFile = new File(newFilePath);
    await newFile.writeAsBytes(bytes);
    return newFilePath;
  }

My working file encryption and decryption code in PHP is:

function encryptFile($encKey, $encIV, $inPath, $outPath) {
        $text=file_get_contents($inPath);
        $key = base64_decode($encKey);
        $iv = base64_decode($encIV);
        $path_parts = pathinfo($inPath);
        $fileName=$path_parts['filename'];
        $outFile=$outPath.$fileName.'.himu';
        $encrypter = 'aes-256-cbc';
        $encrypted = openssl_encrypt($text, $encrypter, $key, 0, $iv);
        if(file_put_contents($outFile,$encrypted)!= false) return 1;
        else return 0;
    }

function decryptFile($encKey, $encIV, $inPath, $outPath) {
        $text=file_get_contents($inPath);
        $key = base64_decode($encKey);
        $iv = base64_decode($encIV);
	$path_parts = pathinfo($inPath);
        $fileName=$path_parts['filename'];
        $outFile=$outPath.$fileName.'.mp4';
        $encrypter = 'aes-256-cbc';
        $decrypted = openssl_decrypt($text, $encrypter, $key, 0, $iv);
        if(file_put_contents($outFile,$decrypted)!= false) return 1;
        else return 0;
    }

Can you Please help me out of this problem. I am badly stuck

[leocavalcante]

@HimanshuSaikia
Read the file as binary and do not pass its content through base 64 decoding (i.e.: enc.Encrypted.fromBase64(text)) it's not saved as base 64, its plain binary.

[HimanshuSaikia]

@HimanshuSaikia
Read the file as binary and do not pass its content through base 64 decoding (i.e.: enc.Encrypted.fromBase64(text)) it's not saved as base 64, its plain binary.

Bro, But decrypt function encrypter.decrypt() returns a string!!
Also, the function is not running on passing a byte array.

[leocavalcante]

Bro, checkout encryptBytes and decryptBytes: https://pub.dev/documentation/encrypt/latest/encrypt/Encrypter/encryptBytes.html ;)

[armandohackcode]

@HimanshuSaikia thanks, it worked very well for me, I used it as a base to make my function to decrypt a text based on the same encryption logic done with php and Lumen

 import 'dart:convert';
 import 'package:encrypt/encrypt.dart' as enc;
 import 'dart:async';
 import 'package:php_serializer/php_serializer.dart';

 Future<String> decryptInfo(String data) async {
       var encodedKey = 'FCAcEA0HBAoRGyALBQIeCAcaDxYWEQQPBxcXH****** example';
       var decoded = base64.decode(data);
      var payload = json.decode(String.fromCharCodes(decoded));
      String encodedIv = payload["iv"]?? "";
      String value = payload["value"] ?? "";
      print(decoded);
      print(payload);
      print (encodedIv);
      final key1 = enc.Key.fromBase64(encodedKey);
      final iv = enc.IV.fromBase64(encodedIv);
     final encrypter = enc.Encrypter(enc.AES(key1, mode: enc.AESMode.cbc));
     final decrypted = encrypter.decrypt(enc.Encrypted.fromBase64(value), iv: iv);
     print(phpDeserialize(decrypted));
   return decrypted;
  } 

[udoy-touhid]

@leocavalcante @HimanshuSaikia
Kudos to both you guys. This thread has really been helpful and save me after quite some headache.

[udoy-touhid]

@HimanshuSaikia I'm just confused in one line.

$encrypted = openssl_encrypt($text, $encrypter, $key, 0, $iv);

if $encrypted contains only binary data, why we need to base64 decode it first on dart?

encryptedBase64EncodedString = new File(filePath).readAsStringSync();
var decoded = base64.decode(encryptedBase64EncodedString);

Could you please clarify?

[Vidwath23]

Hii @HimanshuSaikia

can you please share a complete code it helps me a lot

[mohamaddoost]

hi, can anyone explain that how can encode in flutter and decode in php?