Description:
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I'm doing a webshop system, and I think, I have found a strange bug in mcrypt.
I have to encrypt a string with a number(secret PIN), then encode it with base64, and insert it to a datebase (MySQL).

Then in the admin frontend for my shop, I have to decode and decrypt it, to show it to the shop administrator.
This works in the most of cases. But for example when the PIN is "1234" and the key is "ganzgehein", and I try to decrypt it, it only produces binary rubbish, instead of the expected PIN.
I can't reproduce this bug in a single example file, so i have to upload my complete project. Sorry it's in german language, but there is not very much text, so I think you can understand it by using a automatic translator like Googles.

PS: I am using XAMPP

Test script:
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http://www.file-upload.net/download-3032467/mcrypt_bug_demo.zip.html

It's hosted on file-upload.net because I can't install a ftp client on this machine.

Expected result:
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See notice_for_bugreport.txt for details.