Ron Rivest, Adi Shamir, and Leonard Adleman, MIT mathematicians, publish in August 1977 the RSA algorithm (from their initials) in "A Method for Obtaining Digital Signatures and Public-Key Cryptosystems" (Communications of the ACM). The system uses the multiplication of two large prime numbers as a one-way trapdoor: easy to compute in one direction, computationally infeasible to invert without the private key. RSA becomes the dominant public-key algorithm of the internet era: it underlies TLS/HTTPS, digital signatures, and SSL certificates. Clifford Cocks at GCHQ had developed an equivalent system in 1973, classified and declassified in 1997. Rivest, Shamir, and Adleman received the Turing Award in 2002.