Generation of key ID's

[Ralf Ramsauer]

Hi,

just a short question:
When a new GPG key gets generated, then in fact and by default two key
pairs get generated. Let's assume we deployed RSA-RSA.

Both, signature and encryption key get their own ID's. How are these
ID's generated? Randomly?
Or are they some kind of checksum of the modulus of the key? And why is
it done that way?

I had a look into the source, but I wasn't able to find it out straight
away.
Sure someone of you knows this by heart :-)

Thanks in advance!

-- 
Ralf Ramsauer

PGP: 0x8F10049B