Along with RC4, RC2 with a 40-bit key size was treated favourably under US export regulations for cryptography.

Elliptic curves are also used in several integer factorization algorithms that have applications in cryptography, such as Lenstra elliptic curve factorization.

Public-key cryptography uses asymmetric key algorithms ( such as RSA ), and can also be referred to by the more generic term " asymmetric key cryptography.

In cryptography, RC4 ( also known as ARC4 or ARCFOUR meaning Alleged RC4, see below ) is the most widely used software stream cipher and is used in popular protocols such as Secure Sockets Layer ( SSL ) ( to protect Internet traffic ) and WEP ( to secure wireless networks ).

He also relates his subsequent work in cryptography with Steve Pohlig ( the Pohlig – Hellman system ) and others.

He also touches on the commercialization of cryptography with RSA Data Security and VeriSign.

This idea, known as the " Polybius square ", also lends itself to cryptography and steganography.

Karn also appeared before both House and Senate committees looking at cryptography issues.

It has also facilitated research on new cryptosystems that are secure from quantum computers, collectively called post-quantum cryptography.

In cryptography, a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques.

In cryptography, Kerckhoffs's principle ( also called Kerckhoffs's Desiderata, Kerckhoffs's assumption, axiom, or law ) was stated by Auguste Kerckhoffs in the 19th century: A cryptosystem should be secure even if everything about the system, except the key, is public knowledge.

They are also used in cryptography.

It's also possible to protect messages in transit ( i. e., communications ) by means of cryptography.

Shamir has also made contributions to computer science outside of cryptography, such as finding the first linear time algorithm for 2-satisfiability and showing the equivalence of the complexity classes PSPACE and IP.

The man-in-the-middle attack ( often abbreviated MITM, MitM, MIM, MiM, also known as a bucket brigade attack, or sometimes Janus attack ) in cryptography and computer security is a form of active eavesdropping in which the attacker makes independent connections with the victims and relays messages between them, making them believe that they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker.

In cryptography, a scytale (, rhymes approximately with Italy ; also transliterated skytale, Greek σκυτάλη " baton ") is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message.

It is also risky because the supposed user-generated event ( e. g., keystrokes ) can be spoofed by a sufficiently ingenious attacker, allowing control of the " random values " used by the cryptography.

Although quadratic residues appear to occur in a rather random pattern modulo n, and this has been exploited in such applications as acoustics and cryptography, their distribution also exhibits some striking regularities.

It is also possible to encapsulate messages encrypted with illegal strong cryptography inside messages encrypted with legal weak cryptography, thus making it difficult and uneconomical for outsiders to notice the use of illegal encryption.

In cryptography, a public key certificate ( also known as a digital certificate or identity certificate ) is an electronic document which uses a digital signature to bind a public key with an identity — information such as the name of a person or an organization, their address, and so forth.

Because of its more general utility, the remainder of this article will deal primarily with classical information, although quantum information theory does also have some potential applications ( quantum computing, quantum cryptography, quantum teleportation ) that are currently being actively explored by both theorists and experimentalists.

: See also: Public key cryptography, Blind signature, Digital credential

RSA was named after the initials of its co-founders, Ron Rivest, Adi Shamir, and Len Adleman, after whom the RSA public key cryptography algorithm was also named.

He also describes the commercialization of cryptography with RSA Data Security and VeriSign.

No asymmetric-key algorithms with this property are known ; elliptic curve cryptography comes the closest with an effective security of roughly half its key length.

Leo Marks describes inventing such a system for the British Special Operations Executive during World War II, though he suspected at the time that it was already known in the highly compartmentalized world of cryptography, as for instance at Bletchley Park.

Most major belligerents attempted to solve the problems of complexity and security presented by using large codebooks for cryptography with the use of ciphering machines, the most well known being the German Enigma machine.

It is often incorrectly called quantum cryptography, as it is the most well known example of the group of quantum cryptographic tasks.

Elliptic curve cryptography may allow smaller-size keys for equivalent security, but these algorithms have only been known for a relatively short time and current estimates of the difficulty of searching for their keys may not survive.

In accordance with Kerckhoffs's principle, the majority of civilian cryptography makes use of publicly known algorithms.

During this time, Friedman wrote a series of 23 papers on cryptography, collectively known as the " Riverbank publications ", including the first description of the index of coincidence, an important mathematical tool in cryptanalysis.

Originally an abstract mathematical concept from the branch of number theory known as modular arithmetic, quadratic residues are now used in applications ranging from acoustical engineering to cryptography and the factoring of large numbers.

In cryptography, a Feistel cipher is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel who did pioneering research while working for IBM ( USA ); it is also commonly known as a Feistel network.

Martin Edward Hellman ( born October 2, 1945 ) is an American cryptologist, and is best known for his invention of public key cryptography in cooperation with Whitfield Diffie and Ralph Merkle.

# Using asymmetric key cryptography, the originator uses the public key ( obtained from the directory ) of the first node in the circuit, known as the entry node, to send it an encrypted message, called a create cell, containing:

In cryptography, a key derivation function ( or KDF ) derives one or more secret keys from a secret value such as a master key or other known information such as a password or passphrase using a pseudo-random function.

In Haruki Murakami's novel Hard-Boiled Wonderland and the End of the World, a class of mental calculators known as Calcutecs perform cryptography in a sealed-off portion of their brains, the results of which they are unable to access from their normal waking consciousness.

An early example of a book about cryptography was a Roman work, now lost and known only by references.

The earliest known use of cryptography is found in non-standard hieroglyphs carved into monuments from the Old Kingdom of Egypt circa 1900 BC.

Herodotus tells us of secret messages physically concealed beneath wax on wooden tablets or as a tattoo on a slave's head concealed by regrown hair, though these are not properly examples of cryptography per se as the message, once known, is directly readable ; this is known as steganography.

In cryptography, a ciphertext-only attack ( COA ) or known ciphertext attack is an attack model for cryptanalysis where the attacker is assumed to have access only to a set of ciphertexts.

In cryptography, the Polybius square, also known as the Polybius checkerboard, is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist.