Karl said:

Also, p and q should differ in length by a few digits otherwise an enemy may begin to try factoring n by starting near sqrt(n).

When PGP generates keys doesn't it always pick d and e to have the same number of bits, ie 446 for the strongest type? Is this the same thing? I suppose that if you are allowed leading 0s it isn't a problem at all, but if the first couple of bits were ones in each key, (a 16:1 chance) wouldn't that significantly reduce the power required to factor the PK using this approach? Just a thought, Jim