Re:5th Amendment (Score 2, Informative)

That's not how Public Key encryption generally works.

Encrypting something via Public Key system is slow, so what is generally done is a random key (128bit/256bit/1024bit/whatever) is generated, and some other system like IDEA/Blowfish/etc is used to encrypt the file with this random key. Then the random key itself is encrypted using the Public Key, and included in the output file (or this may be done first).

Encrypting the same file twice with PGP/GPG will result in different encrypted files. Here is what I got when I encrypted the same file twice:

$ ls -l whycopyrightdoc.ogg*
-rw-r--r-- 1 xxxx users 444876583 2008-12-09 16:27 whycopyrightdoc.ogg
-rw-r--r-- 1 xxxx users 442961134 2009-02-27 13:38 whycopyrightdoc.ogg.gpg
-rw-r--r-- 1 xxxx users 442961133 2009-02-27 13:33 whycopyrightdoc.ogg.gpg.1

$ cksum whycopyrightdoc.ogg*
2090966688 444876583 whycopyrightdoc.ogg
909254713 442961134 whycopyrightdoc.ogg.gpg
121574791 442961133 whycopyrightdoc.ogg.gpg.1