Rivest-Shamir-Adleman (RSA)
Ron Rivest, Adi Shamir, and Leonard Adleman invented RSA in 1977. This encryption uses huge prime numbers and the difficulty of factoring large composite numbers. RSA encrypts and decrypts using public and private keys. The public key is disclosed, but the secret key is concealed. This enables keyless secure communication. Bob’s public key lets Alice send Bob an RSA-encrypted message. Bob’s private key decrypts the message. Digital signatures and key exchange use RSA. RSA is slower than AES and unsuitable for big data encryption owing to its computational complexity.