lib/Crypt/OpenPGP/Certificate.pm
106:sub key_id_hex { uc unpack 'H*', $_[0]->key_id }

##</code><code>##

print "KeyID hex long: 0x", uc         unpack('H*', $sigobj->key_id)        ,"\n";
print "KeyID hex short: 0x",uc substr( unpack('H*', $sigobj->key_id), -8, 8),"\n";