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c#encryptioncompression
Niyaz
Niyaz

Reputation: 54823

Are there any compression and encryption libraries in C#?

I want to compress some files (into the ZIP format) and encrypt them if possible using C#. Is there some way to do this?

Can encryption be done as a part of the compression itself?

Upvotes: 3

Views: 4674

Answers (9)

Skizz
Skizz

Reputation: 71130

For compression, look at the System.IO.Compression namespace and for encryption look at System.Security.Cryptography.

Upvotes: 12

Martin Plante
Martin Plante

Reputation: 4703

I know the question is already old, but I must add my two cents.

First, some definitions:

  • Zip: Archive format for regrouping files and folders into a single file, and optionally encrypting data.
  • Deflate: One of the compression algorithms used within a Zip file to compress the data. The most popular one.
  • GZip: A single file compressed with deflate, with a small header and footer.

Now, System.IO.Compression does not do Zip archiving. It does deflate and gzip compression, thus will compress a single blob of data into another single blob of data.

So, if you're looking for an archive format that can group many files and folders, you need Zip libraries like:

If you only need to compress and encrypt a single blob of data, then look under System.IO.Compression and System.Security.Cryptography.

Upvotes: 6

Ian Nelson
Ian Nelson

Reputation: 58783

Chilkat provides .NET libraries for compression and encryption.

Upvotes: 1

Rik
Rik

Reputation: 29243

If they cannot be combined, do compression first and then encryption. Compressing an already encrypted file will lead to poor compression ratios, because a lot of redundancy is removed.

Upvotes: 0

prakash
prakash

Reputation: 59719

For Zip Compression, have you seen http://www.icsharpcode.net/OpenSource/SharpZipLib/

Upvotes: 7

Hank Gay
Hank Gay

Reputation: 72039

I'm not sure if the steps can be combined, but .NET has good support for basic crypto. Here's an article on it.

Upvotes: 0

Mark Ingram
Mark Ingram

Reputation: 73713

There isn't anything you can use directly in C#, however you can use some libraries from J# to do it for you:

http://msdn.microsoft.com/en-us/magazine/cc164129.aspx

Should do just what you want?

With regards to the encryption, have a look at these links:

http://www.codeproject.com/KB/security/fileencryptdecrypt.aspx

http://www.obviex.com/samples/EncryptionWithSalt.aspx

Upvotes: -1

Vinko Vrsalovic
Vinko Vrsalovic

Reputation: 340496

The GZipStream class is a native way to handle compression.

As for encryption, there are many ways to do it, most of them in the System.Security namespace. They can be done chained (encrypt a compressed stream or compress an encrypted stream).

Upvotes: 1

aku
aku

Reputation: 124044

Here is a useful topic:

Help in creating Zip files from .Net and reading them from Java

System.IO.Packaging namespace gives you useful classes to compress data in zip format and support rights management.

Upvotes: -1

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