What is PGP and public key

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mahaju
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Joined: Mon 11 Oct 2010, 07:11
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What is PGP and public key

#1 Post by mahaju »

I know what is Public Key and how Public Key cryptography works
But what exactly is that thing which people post on their websites as their public? What I meant to ask was how do I use it?
For example, I found this on a personal website

Code: Select all

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.3 (GNU/Linux)
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=8jDV
-----END PGP PUBLIC KEY BLOCK-----
So now I know his public key. But how can I use it now?

Also, please see this

http://xkcd.com/364/


What is the joke here? What happens if you sign the public key? I guess you sign some document using your private key. So what does it do if you sign someone else's public key? Does it make your private key insecure? Or does it make it look like you are verifying that particular public key?

Please shed some light into this.

Thank you very much for your invaluable time.


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