Recommendations on a free library to be used for zipping files [closed]
You can try Zip4j, a pure java library to handle zip file. It supports encryption/ decryption of PKWare and AES encryption methods.
Key features:
- Create, Add, Extract, Update, Remove files from a Zip file
- Read/Write password protected Zip files
- Supports AES 128/256 Encryption
- Supports Standard Zip Encryption
- Supports Zip64 format
- Supports Store (No Compression) and Deflate compression method
- Create or extract files from Split Zip files (Ex: z01, z02,...zip)
- Supports Unicode file names
- Progress Monitor
License:
- Zip4j is released under Apache License, Version 2.0.
UPDATE 2020: There are other choices now, notably Zip4J.
After much searching, I've found three approaches:
A freely available set of source code, suitable for a single file zip. However, there is no license. Usage is AesZipOutputStream.zipAndEcrypt(...).http://merkert.de/de/info/zipaes/src.zip(https://forums.oracle.com/forums/thread.jspa?threadID=1526137)
UPDATE: This code is now Apache licensed and released at https://github.com/mobsandgeeks/winzipaes (exported from original home at Google code) . It worked for me (one file in the zip), and fills a hole in Java's opens source libraries nicely.
A commercial product ($500 at the time of writing). I can't verify if this works, as their trial license approach is complex. Its also a ported .NET app:http://www.nsoftware.com/ipworks/zip/default.aspx
A commercial product ($290 at the time of writing). Suitable only for Wnidows as it uses a dll:http://www.example-code.com/java/zip.asp
This isn't an answer, but it is a caution to keep in mind when evaluating potential solutions.
One very important thing about zip encryption:
There are several types of zip encryption. The old type (part of the original zip standard) is not at all worth bothering with (it can be cracked in less than 10 minutes with apps easily available online).
If you are doing any sort of encryption of zip files, please, please be sure you use one of the strong encryption standards (I believe that WinZip's 128- and 256-bit AES standard is the best supported). Here are the technical specs - we used this when developing our own Java encrypted zip system (can't provide source - sorry - it's internal use only)
The only thing worse than having no encryption is thinking that you have encryption and being wrong :-)