improved cbc performance

[Medosopher]

The sublist commands only had their start argument set and at each iteration they take a sublist from the start all the way to the end. Now while that's trivial in small texts, it becomes a significant burden once the size and iteration goes up. for instance once the byte length goes from 400,000 to 800,000 the time takes goes from 2 seconds to 12 seconds and once we go above 1 million it just goes up even more exponentially. You can try the following code snippet which yields these results to prove this point: Encrypted string, length: 400000, encrypted-length:400016, lasted 0:00:01.949904 Encrypted string, length: 800000, encrypted-length:800016, lasted 0:00:12.915183 Encrypted string, length: 1600000, encrypted-length:1600016, lasted 0:01:10.960904 which becomes the following results following this fix: Encrypted string, length: 400000, encrypted-length:400016, lasted 0:00:00.051635 Encrypted string, length: 800000, encrypted-length:800016, lasted 0:00:00.042980 Encrypted string, length: 1600000, encrypted-length:1600016, lasted 0:00:00.084371

On a further note, are you still looking for someone to take over the maintenance of this module?

here's the code that produces the log :

import 'package:encrypt/encrypt.dart';

var stopwatch = new Stopwatch()..start(); void log(message) { print('$message, lasted ${stopwatch.elapsed}'); stopwatch.reset(); }

void encrypt_and_decrypt(String str) { final iv = IV.fromBase16('95c4735086a5c909d66568592af98b28'); final encrypter = Encrypter(AES(Key.fromBase16('2bb551c379dea568c4309323a29d9fdd3db9b4ec6b77951fa90359e82e8501ac'), mode: AESMode.cbc)); log('Encrypter created'); var encrypted = encrypter.encrypt(str, iv: iv); log('Encrypted string, length: ${str.length}, encrypted-length:${encrypted.bytes.length}'); var decrypted = encrypter.decrypt(encrypted, iv:iv); log('Decrypted string, length: ${str.length}, decrypted-length:${decrypted.length}, equality: ${str==decrypted}'); }

void main(List arguments) { encrypt_and_decrypt(List.filled(400 1000, 'a').join()); encrypt_and_decrypt(List.filled(800 1000, 'a').join()); encrypt_and_decrypt(List.filled(1600 * 1000, 'a').join()); }

[AKushWarrior]

you should probably refile this @ https://github.com/bcgit/pc-dart

This project has moved there.

[Medosopher]

Unfortunately I can't see this repo you've linked to.

[AKushWarrior]

Whoops, added an extra hyphen.

Should be fine now. @Medosopher

[Medosopher]

Thanks. But what happens to all the packages using pointycastle then? no further updates?

[Medosopher]

Cool, I see that someone has already resolved this issue in pc-dart.

[AKushWarrior]

@Medosopher There's plans to publish the new updates to https://pub.dev. There's an issue that you could track in the other repo.