Invalid or corrupted pad block about encrypt

[leocavalcante]

Sorry the delay.
Added the option to use AES without padding, just give a null value to it:

Encrypter(AES(key, iv, mode: AESMode.ecb, padding: null))

Does it helps?

[preetshah21699]

I understand that there is a fix. But the fix isn't backwards compatible. How is someone supposed to use an encryption tool/package if there is no guaratee that they will be able to decrypt the data in the future. I understand that there must have been a bug fix or something that required you to make this change. But the basic functioning of the package should remaing the same and it should be backwards compatible.

[leocavalcante]

Hi, folks
Please, just replace IV.fromLength(16) by IV.allZerosOfLength(16).
As saw in #314
Remember that it is not cryptography safe

[preetshah21699]

I am facing this issue right now with the version 5.0.3.

However, when I was using version 5.0.1, it didn't have this issue. So, now I have data already encrypted and stored on the server with the defaault padding values.

I believe, the default mode was sic and padding PKCS7.

aes1Key = Key.fromUtf8(aes1Text);
aesKey = Key.fromUtf8(aesText);
aes1Encrypter = Encrypter(AES(aes1Key));
aesEncrypter = Encrypter(AES(aesKey));

If I use null for padding, it works. But it cannot decrypt my old data properly that was encrypted using the older library.

[alfatlaloc]

Same issue here, version 5.0.3 just cant decrypt, thankfully the app is not in production yet

[leocavalcante]

You need the proper key and iv values to decode...

[chinabrant]

static List<int> aes128Encode(String params) {
    final key = Key.fromUtf8('15helloTCJTALK20'); 
    final iv = IV.fromLength(16);
    final encrypter = Encrypter(AES(key, iv, mode: AESMode.ecb));

    final encrypted = encrypter.encrypt(params);
    final result = encrypter.decrypt(encrypted);
    print('params: $params');
    print('result: $result');

    return encrypted.bytes;
  }

  static List<int> aes128Decode(List<int> data) {
    final key = Key.fromUtf8('15helloTCJTALK20');
    final iv = IV.fromLength(16);
    final encrypter = Encrypter(AES(key, iv, mode: AESMode.ecb));

    final encrypted = Encrypted(Uint8List.fromList(data)); 

    return encrypter.decrypt(encrypted).runes.toList();
  }

Use aes128Encode function, i can get the right answer.

AES(this.key, this.iv, {this.mode = AESMode.sic})
      : _cipher = PaddedBlockCipher('AES/${_modes[mode]}/PKCS7'),
        _params = PaddedBlockCipherParameters(
          mode == AESMode.ecb
              ? KeyParameter(key.bytes)
              : ParametersWithIV<KeyParameter>(
                  KeyParameter(key.bytes), iv.bytes),
          null,
        );

Look at aes class define, when the mode is AESMode.ecb, the iv parameter is no use.

[leocavalcante]

Your code looks fine here:

import 'package:encrypt/encrypt.dart';
import 'dart:typed_data';

class Encoder {
  static List<int> aes128Encode(String params) {
    final key = Key.fromUtf8('15helloTCJTALK20');
    final iv = IV.fromLength(16);
    final encrypter = Encrypter(AES(key, iv, mode: AESMode.ecb));

    final encrypted = encrypter.encrypt(params);
    final result = encrypter.decrypt(encrypted);
    print('params: $params');
    print('result: $result');

    return encrypted.bytes;
  }

  static List<int> aes128Decode(List<int> data) {
    final key = Key.fromUtf8('15helloTCJTALK20');
    final iv = IV.fromLength(16);
    final encrypter = Encrypter(AES(key, iv, mode: AESMode.ecb));

    final encrypted = Encrypted(Uint8List.fromList(data));

    return encrypter.decrypt(encrypted).runes.toList();
  }
}

void main() {
  final text = 'Lorem Ipsum';
  final encoded = Encoder.aes128Encode(text);

  print(encoded);

  final decoded = Encoder.aes128Decode(encoded);

  print(decoded);
}

encrypt_issu30~ dart .\bin\main.dart
params: Lorem Ipsum
result: Lorem Ipsum
[193, 56, 172, 130, 112, 33, 0, 154, 30, 140, 46, 16, 54, 73, 41, 239]
[76, 111, 114, 101, 109, 32, 73, 112, 115, 117, 109]

I'm missing something?

[chinabrant]

I know why, the server data don't need the pkcs7padding to decrypt. So what should i do.

PaddedBlockCipher('AES/${_modes[mode]}/PKCS7'),

[chinabrant]

This is the encrypt function at client.

- (NSData *)AES128EncryptWithKey:(NSString *)key {
	// 'key' should be 128 bytes for AES128, will be null-padded otherwise
	char keyPtr[kCCKeySizeAES128+1]; // room for terminator (unused)
	bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
	
	// fetch key data
	[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
	
	NSUInteger dataLength = [self length];
	
	//See the doc: For block ciphers, the output size will always be less than or 
	//equal to the input size plus the size of one block.
	//That's why we need to add the size of one block here
	size_t bufferSize = dataLength + kCCBlockSizeAES128;
	void *buffer = malloc(bufferSize);
	
	size_t numBytesEncrypted = 0;
	CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding + kCCOptionECBMode,
										  keyPtr, kCCKeySizeAES128,
										  NULL /* initialization vector (optional) */,
										  [self bytes], dataLength, /* input */
										  buffer, bufferSize, /* output */
										  &numBytesEncrypted);
    
	if (cryptStatus == kCCSuccess) {
		//the returned NSData takes ownership of the buffer and will free it on deallocation
		return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
	}
	
	free(buffer); //free the buffer;
	return nil;
}

This is the decrypt function.

- (NSData *)AES128DecryptHttpWithKey: (NSString *)key {
    // 'key' should be 16 bytes for AES128, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES128+1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
    
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSUInteger dataLength = [self length];
    
    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    
    size_t numBytesDecrypted = 0;
    
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionECBMode,
                                          keyPtr, kCCKeySizeAES128,
                                          NULL /* initialization vector (optional) */,
                                          [self bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesDecrypted);
    
    if (cryptStatus == kCCSuccess) {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
    
    free(buffer); //free the buffer;
    return nil;
}

In the two function, the third parameter is different at CCCrypt invoke.

[chinabrant]

thanks

[YDJSZY]

I have the same error, what's the reason ?

[KonKri]

It worked, I was working on a message I had received encrypted with AES 128 ECB, and I had the same issue! Can you add it to the documentation?. Thanks anyways!!

[leocavalcante]

It is already there https://github.com/leocavalcante/encrypt#nozero-padding

[ismaeldmlv]

I am facing this issue right now with the version 5.0.3.

However, when I was using version 5.0.1, it didn't have this issue. So, now I have data already encrypted and stored on the server with the defaault padding values.

I believe, the default mode was sic and padding PKCS7.

aes1Key = Key.fromUtf8(aes1Text);
aesKey = Key.fromUtf8(aesText);
aes1Encrypter = Encrypter(AES(aes1Key));
aesEncrypter = Encrypter(AES(aesKey));

If I use null for padding, it works. But it cannot decrypt my old data properly that was encrypted using the older library.

same bug on update to 5.0.3...
i fixed changing:
final iv = IV.fromLength(16);
to:
final iv = IV.fromUtf8('KeyWith16CharsHere');
but of course it not work for decrypt data encrypted by version 5.0.1 because we change the IV.

[oliverbytes]

Same issue here as well

[alfonsotesone]

Same problem here with 5.0.3

[emadal95]

I am having the same problem. Data already encrypted is not decrypting anymore. This is a huge issue, is anything being done to fix this?

UPDATE:
for anyone with this problem still and not able to decrypt old data, the old IV string created with IV.fromLength() (in base64 below) was AAAAAAAAAAAAAAAAAAAAAA==
substitute your IV.fromLength(16) with IV.fromBase64('AAAAAAAAAAAAAAAAAAAAAA=='). this should let you at least decrypt the old password so you can now adjust to the new package encryption

[ghazalcomputer]

I have the same problem
Why did you close the issue?
Please check again
There is the same problem again

[alfatlaloc]

Hey, i found a solution. I don´t know how good it is but . . .

My use case is that i need new key and IV every login, except for some cases but almost every time is like that.

I made a function that creates a random String from the characters bellow.

String _generateRandom(int length) {
    const String allowedChars =
        'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    final random = Random();
    final buffer = StringBuffer();
    for (var i = 0; i < length; i++) {
      final charIndex = random.nextInt(allowedChars.length);
      buffer.write(allowedChars[charIndex]);
    }
    return buffer.toString();
  }

And i just use the generated values

      final encrypter =
          Encrypter(AES(Key.fromUtf8(secret.key)));
      final encrypted = encrypter.encrypt(original, iv: IV.fromUtf8(secret.iv));