This algorithm emerged in 1978. It was the first algorithm that could be used for both data encryption and digital signatures. It is easy to understand and operate, which made it very popular. The algorithm was named after its inventors: Ron Rivest, Adi Shamir, and Leonard Adleman. However, the security of RSA has never been theoretically proven.
The security of RSA relies on the factorization of large numbers. Both the public key and private key are functions of two large prime numbers (greater than 100 decimal digits). It is conjectured that the difficulty of inferring the plaintext from a key and ciphertext is equivalent to factoring the product of two large prime numbers.