the encoding mechanism

Question

can i know what the encoding mechanism is used here to encode the key below ?

-----BEGIN PGP PUBLIC KEY BLOCK-----Version: SKS 1.1.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NhFO-----END PGP PUBLIC KEY BLOCK-----

Answer 1

It is a public PGP key encoded using Radix64 (OpenPGP's variant of Base64) -- "armored". You usually don't need to decode it - you just import it to gpg or PGP software.

The key in your post is missing a few newlines though (and won't be recognized by GPG if it's in a single line). It should look like this:

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.0
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NhFO
-----END PGP PUBLIC KEY BLOCK-----

gpg says the key belongs to...

pub  1024D/1278A1862492D908 2003-12-15 God <God@heaven.com>
sub  2048g/1641295AEB24507A 2003-12-15

The above is output of this command:

gpg somekey.txt

To see more information about the data blocks in this key (or any data written by PGP), use:

gpg -vv somekey.txt

And to import it to your local keyring, use:

gpg --import somekey.txt

Answer 2

As Greg said, it's better suited for superuser.com.

However, here's an answer: The block you see is a "ASCII armored" PGP (or GPG) public key which can be used to encrypt data using PGP/GPG tools. The data encrypted with this key can only be decoded by the holder of the corresponding private key. There's no need (and use) to "decode" it.