1. In March 1998 Ron Rivest authored an RFC publicly describing RC2 himself.

2. The MD4 Message-Digest Algorithm is a cryptographic hash function developed by Ronald Rivest in 1990.

3. Soon afterwards, Ronald Rivest, Adi Shamir, and Len Adleman invented the RSA algorithm, which could be used to produce primitive digital signatures (although only as a proof-of-concept – "plain" RSA signatures are not secure).