This memo describes a key-exchange method for the Secure Shell (SSH) protocol based on Rivest-Shamir-Adleman (RSA) public-key encryption. It uses much less client CPU time than the Diffie-Hellman algorithm specified as part of the core protocol@ and hence is particularly suitable for slow client systems.
RFC 4432-2006 history
2006RFC 4432-2006 RSA Key Exchange for the Secure Shell (SSH) Transport Layer Protocol