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RSA - Ron Rivest, Adi Shamir and Leonard Adleman

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  • RSA - Ron Rivest, Adi Shamir and Leonard Adleman

    RSA is an asymmetric encryption that provides authenticity and non-repudiation.
    The shortening is made from the sir names of the authors Ronald Rivest, Adi Shamir and Leonard Adleman.
    This kind of encryption gives user authenticity because the key is bound to a user and not a host.
    Asymmetric encryption involves a keypair. A public and a private key and is a form om public-key cryptography.
    Anything encrypted with the private key can only be decrypted with the public key and anything encrypted with the public key can only be decrypted with the private key so these kinds of keys are one way keys.
    As the private key is bound to a user anything encrypted with the private key that decrypts with the public key must therefore come from the user that own the private key. This is non-repudiation.

    This kind of encryption have a lot larger key sizes than symmetric encryption and might be 100 or even 1000 times slower than symmetric encryption because of the huge prime numbers and the factoring. Because of this, RSA is most often used to protect a symmetric key in transit for use with faster symmetric cryptography.

    This kind of encryption system provides digital signatures, encryption and key exchange used in a cryptosystem. Cryptosystem is the mechanism that carries out the encryption and decryption process. Algorithm, key, software etc.

    RSA was invented in April 1977 by Rivest, Shamir and Adleman, however, according to the British Government, public-key cryptography was originally invented by James Ellis in the Communications-Electronics Security Group (CESG) at the Government Communications HeadQuaters (GCHQ) in Cheltenham four years earlier, in 1973. The use of prime numbers and factoring was was added by Clifford Cocks. By 1975, James Ellis, Cliff Cocks and his mentor Malcolm Williamson had discovered all the fundamental aspects of public-key cryptography even before the Diffie-Hellman-Merkle key exchange was invented. This information was classified until December 18th 1997 so history had to be rewritten.
    The source of this is "The Code Book - The Secret History of Codes and Codebreaking" by PhD Simon Singh (ISBN 978-1-85702-889-8, 2000 - Fourth Estate).
    Certified Security Geek