Free dll for Asymmetric encryption in C#

Can anyone help me out to finding any free dll for asymmetric encryption for larger (non 开发者_如何学运维plain text like zip files, pdf's etc.) data. Currently availble classes in C# .NET are for asymetric encryption, is limited to plain text ( not more than 100 bytes) data only. My need is to encrypt/decrypt larger zip(of pdf fies) data in Asymmetric method.

Any suggestions is appreciated.

Thanks

The point is, that - generally speaking - you don't use public/private key encryption for large data, due to its slower performance (compared to symmetric methods).

In general, you use an asymmetric cipher to encrypt a symmetric key, that in turn you then use to encrypt/decrypt your actual data.

See here or here ("How it works").

The asymmetric encryption built-in to .NET supports large binary files. Review

http://msdn.microsoft.com/en-us/library/system.security.cryptography.aspx

Can you share why you think only short texts are supported?