Encryption type in sharpziplib

Question

I'm using sharplibzip to zip my files with password. I cannot find, what encryption does it use - I need to know that to decide, if I can be sure no one is able to unzip without knowing the password. I can use very long password in my app too.

EDIT: So, this library can use AES encryption, you have ZipEntry.AESKeySize for that. And if you use 128 or longer keysize - that will be practically uncrackable.

Answer 1

SharpZipLib uses PkzipClassic and AES.

if I can be sure no one is able to unzip without knowing the password

If you use AES with a key size of 128 or higher, then yes, you can be sure. Please see this article:
http://www.eetimes.com/document.asp?doc_id=1279619
According to that article, it would take 3.31 * 10⁵⁶ years to crack a 256-bit key.