Encrypt conversations

I want to develop an application that encrypt all my conversations that I have. MSN conversations, Google Talk conversations, or any other.

How can I develop an application like that? What is the best architecture?

What can I use to achieve this... What encryption protocol?

Thanks.

P.S.: I want to开发者_StackOverflow use Java.

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Like Telcontar said: Build upon an existing open source software.

Try Pidgin + the OTR plugin (Off The Record encryption) as a basis. With this combination you have all necessary stuff and you can include a source for all public keys.

A secured central Website for your contacts could be referenced, too. So every user could just open this webpage from Pidgin and receive the matching key. If this website is secured by a well known authority SSL cert, it's perfect.

Pidgin supports Jabber, Google Talk, AIM, Yahoo, ICQ, MSN, whatever and is available for all well-known platforms.

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Off-the-Record Messaging might be the encryption protocol you are looking for.

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I think is not possible as you think of it. If you are encrypting your message the client of your peer must be able to decrypt it. So, both of us need your client.

Maybe you can implement a client that encrypt conversations only when both peers are prepared for that. I think aMSN source code is available and is possible that all you need to create is a plugin.

For encrypting messages fast, the best option is a block encryption algorithm, as AES. First, you need to share a key, e.g. with a public key encryption as RSA.

Keep us in touch about your success ;)

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Find an java opensource application which can use MSN and Jabber (GTalk uses it) protocols and adapt it