Being pedantic: RSA is a cryptosystem, not a protocol, and the parameters that were used in 1980s RSA encryption look nothing like the parameters used in today's RSA (in part because they're much larger now, but also in part because we now know about all the weird things that happen when you choose non-standard exponents, primes that are too close to each other, etc.).
RSA is also not typically described as robust, for those reasons.
