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Monthly Archives: February 2011

Failed Apps

When I wrote my previous post (Cracking Password-Protected ZIP Files – The Smart Way) I realized that “I HAD TO download WinZip”. Something I wouldn’t have normally done.

This is because I stopped using WinZip a while ago. Because of several reasons, but mainly because it became a really commercial app. It was not difficult to replace it: the alternative 7-Zip is all you could ever need from an archive manager, I think! Its fast, small, understands a lot of compression formats, integrates into Windows explorer, etc. And it is free! Really free:

You can use 7-Zip on any computer, including a computer in a commercial 
    organization. You don't need to register or pay for 7-Zip.

But WinZip isn’t the only program I replaced during time:

and probably much more. But all have something in common: they became commercial and now came bundled with a lot of features and other programs I really don’t need. WinZip has a 19 MB download package!!! 7-zip is just 1MB!

Another program which I replaced 2 month ago was Firefox. I replaced it with Google Chrome because Google Chrome is insanely fast on my notebook. It starts faster than any other program I have, even Notepad++ 🙂 Firefox might have been of course altered with all my installed add-ons (which I actually miss in Chrome), but nonetheless, Chrome seems faster in any aspect of web browsing.

So I have at least two reasons for replacing an app:

1. the application and its setup should only serve the application’s initial purpose and

2. speed in all its aspects (download time, installation time, start-up time, functionality speed).

Are there any other reasons why an application would FAIL and be replaced with another?

Cracking Password-Protected ZIP Files – The Smart Way

I’m struggling for some years now to crack a password protected ZIP files that I created 8 years ago. I have tried different brute force programs found on the net, but even though the CPUs are getting faster, it still would still have required probably a lot of years to crack it.

Today I found out that you can decrypt a password protected file if you happen to have an original file, or at least a part of it. These technique is called “Known plain-text attack”. So I realized that I had a file unencrypted and started investigating how I could crack my archive using this file.

Using free tools (like PkCrack) did not help. So I used Elcomsoft Advanced Archive Password Recovery. I managed to crack the archive in less than 1 minute!

But: I spent a lot of time figuring out how to prepare the input for Elcomsoft ARCHPR. I needed to compress the unencrypted file using the same compression level (and program I guess) which I used when I encrypted the files. After struggling with 7-zip and other archive managers, I had to download WinZip. These seemed to have done the trick!

Additionally, my files were inside folders in the archive. I prepared the archives to contain only the files, without the folders. It seems that WinZip can rearrange files in an archive, even if they are encrypted, 7-zip not.

And then the expected happened: using Elcomsoft ARCHPR I had decompressed and decrypted all files in the archive. They have been sitting there for 8 years and probably they would have remained there until the CPUs (or GPUs) would manage to brute-force my archive in a reasonable time.

Now I can enjoy my super-secret-highly-classified encrypted pictures again!

Encouragement to Blogging

In my post here I encouraged developers to have an own blog and to socially interact with other fellow programmers.

Here is another excellent blog entry from Jeff Atwood, from Coding Horror, talking about how to improve communication skills for developers:

Do YOU have a blog?