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Need a good non-patented encryption algo for an application that encrypts files that too only one sided(not like PGP)...

Reading Bruce Schiener book i liked IDEA but sadly its patented.

Does anyone know good non-patented encrption algorithm like Blowfish?
???

whats wrong with blowfish? there is no royalties on using it.

I know Blowfish is awesome.

Just that the application i am trying to write gives the user choice between multiple encrypting algos.

Blowfish is one already included. Its the other options that r still to be decided. thats why....

anubis wrote: Does anyone know good non-patented encrption algorithm like Blowfish?
???

Blowfish is fast gaining more and more acceptance, there is also Twofish from the same author. AES is really good, and it's royalty free for non-commercial use I believe (however it *may* be patented, I can't recall offhand. It is the new standard that replaces DES of course, otherwise known as Rijndael.)

If you can get away with AES, use it. Phil Zimmerman himself recommends its use, and Schneier likes it too; however I personally prefer Blowfish. There's lots of excellent ready-made code out there for both Rijndael and Blowfish/Twofish. IDEA as you say is excellent - but patented (BUT mark you calendars - patents don't last forever. Only 7 years I think!)

Have you read "Practical Cryptography?" It's a follow up in a sense from "Applied Cryptography." It's equally excellent and easier to read with TONS of practical advice for actually getting to the business of implementing crypto along with auxiliary functions like RNGs, rather than just choosing a crypto algorithm.

James Buchanan wrote: Have you read "Practical Cryptography?" It's a follow up in a sense from "Applied Cryptography."

Currently i am reading Crytography in C & C++ by Welschenbach. Its good with lots of code.

Will follow that up by "Practical Crytography". By the way can i know its authors name so i can buy it up?