Wing

Number Theory

3 century BC

Euclidean Algorithm (GCD)

Euclid, ~300 BC

The oldest known non-trivial algorithm, computing the greatest common divisor by repeated division.

2 century BC

Sieve of Eratosthenes

Eratosthenes, ~200 BC

An ancient algorithm for finding all prime numbers up to a given limit by iteratively eliminating multiples.

1970s

Diffie–Hellman Key Exchange

Whitfield Diffie & Martin Hellman, 1976

Public parameters p and g; private exponents a and b; modular exponentiation yields a shared secret without transmitting it.

RSA Key Generation

Ron Rivest, Adi Shamir & Leonard Adleman, 1978

A simplified visualization of RSA public-key cryptography: key generation, encryption, and decryption.