WDS:no, it (RSA for secret key use) is a secret key cryptosystem. It is much more secure against repeated use, than a 1-time pad. I just pointed out, it is much less secure than the usual secret key systems are generally thought to be.
Mike Stay: If M is public, then E is a one-time pad.
--no. If modulus M is public, E secret, and I send x^E mod M as encrypt of message x, then I send y^E mod M as encrypt of message y, then there is no easy way to determine E even for an attacker who knows x and y. And if attacker knows only x, no easy way to determine y or E. So this is much safer than a 1-time pad. But can determine E by solving discrete log problem, so weaker than usual secret key cryptosystems. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)