Re: Prime magnitude and keys...a ?

I was wondering if anyone is aware of a function or test which would allow a person to feed PGP or other RSA algorithm a test key and then look at the result and determine if the key was greater or lesser than the actual key?

I hope not. If such a thing existed (if I understand your description correctly) RSA could be cracked by a binary search of keyspace. The search would be O(log(n)), meaning it would be directly linear with the number of bits in the key.