What is the purpose of all files in ~/.gnupg ?

[Nikolas Garofil]

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What is the meaning of the following files:
gpg.conf     : Configuration of the gpg-program (I think)
pubring.gpg  : Stores all public passwords (I think)
pubring.gpg~ : ?
random_seed  : Used to create good random passwords (just a guess)
secring.gpg  : Stores all secret passwords (I think)
trustdb.gpg  : ?

If i would delete gnupg and install it on a other pc then which files do i 
have to backup ? (i guess i only need secring.gpg)

Nikolas Garofil
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