Serious Cryptography, 2nd Edition

10 RSA

The Rivest–Shamir–Adleman (RSA) cryptosystem revolutionized cryptography when it emerged in 1977 as the first public-key encryption scheme. Whereas classical, symmetric-key encryption schemes use the same secret key to encrypt and decrypt messages, public-key encryption (or asymmetric encryption) uses two keys: a public key, which anyone who wants to encrypt messages for you can use, and a private key, which is required to decrypt messages encrypted using the public key. This magic is the reason why RSA was a real breakthrough, and 40 years later, it’s still the paragon of public-key encryption and a workhorse of internet security. ...