In cryptography, the International Data Encryption Algorithm ( IDEA ) is a block cipher designed by James Massey of ETH Zurich and Xuejia Lai and was first described in 1991.

In cryptography, SAFER ( Secure And Fast Encryption Routine ) is the name of a family of block ciphers designed primarily by James Massey ( one of the designers of IDEA ) on behalf of Cylink Corporation.

In cryptography, MMB ( Modular Multiplication-based Block cipher ) is a block cipher designed by Joan Daemen as an improved replacement for the IDEA cipher.

In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks, with an unvarying transformation that is specified by a symmetric key.

In cryptography, a cipher ( or cypher ) is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure.

In cryptography, key size or key length is the size measured in bits of the key used in a cryptographic algorithm ( such as a cipher ).

Common families include symmetric systems ( e. g. AES ) and asymmetric systems ( e. g. RSA ); they may alternatively be grouped according to the central algorithm used ( e. g. elliptic curve cryptography ).

One of the asymmetric algorithm types, elliptic curve cryptography, or ECC, appears to be secure with shorter keys than those needed by other asymmetric key algorithms.

Derivatives of Shor's algorithm are widely conjectured to be effective against all mainstream public-key algorithms including RSA, Diffie-Hellman and elliptic curve cryptography.

In 2002, Hellman suggested the algorithm be called Diffie – Hellman – Merkle key exchange in recognition of Ralph Merkle's contribution to the invention of public-key cryptography ( Hellman, 2002 ).

" An astonishing share of the open literature in cryptography in the 1970s and 1980s dealt with the DES, and the DES is the standard against which every symmetric key algorithm since has been compared.

Elliptic curve cryptography is vulnerable to a modified Shor's algorithm for solving the discrete logarithm problem on elliptic curves.

In cryptography, encryption is the process of transforming information ( referred to as plaintext ) using an algorithm ( called a cipher ) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key.

An algorithm that efficiently factors an arbitrary integer would render RSA-based public-key cryptography insecure.

* Key ( cryptography ), a piece of information that controls the operation of a cryptography algorithm

RSA is an algorithm for public-key cryptography that is based on the presumed difficulty of factoring large integers, the factoring problem.

In 1995 Adam Back wrote a version of the RSA algorithm for public-key cryptography in three lines of Perl and suggested people use it as an email signature file:

If a quantum computer with a sufficient number of qubits were to be constructed, Shor's algorithm could be used to break public-key cryptography schemes such as the widely used RSA scheme.

It is an open question, and one central to the theory and practice of cryptography, whether there is any way to distinguish the output of a high-quality PRNG from a truly random sequence without knowing the algorithm ( s ) used and the state with which it was initialized.

The algorithm in its native form is not suitable for cryptography ( unlike Blum Blum Shub ).

In cryptography, Triple DES is the common name for the Triple Data Encryption Algorithm ( TDEA or Triple DEA ) block cipher, which applies the Data Encryption Standard ( DES ) cipher algorithm three times to each data block.

In cryptography, a key is a piece of information ( a parameter ) that determines the functional output of a cryptographic algorithm or cipher.

The history of cryptography provides evidence that it can be difficult to keep the details of a widely used algorithm secret ( see security through obscurity ).

He is a co-inventor of the RSA algorithm ( along with Ron Rivest and Len Adleman ), a co-inventor of the Feige – Fiat – Shamir identification scheme ( along with Uriel Feige and Amos Fiat ), one of the inventors of differential cryptanalysis and has made numerous contributions to the fields of cryptography and computer science.

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.

In cryptography, the ElGamal encryption system is an asymmetric key encryption algorithm for public-key cryptography which is based on the Diffie – Hellman key exchange.

Other techniques such as cryptography were previously restricted to military applications.

* Replay attack, in cryptography, an attack where an adversary interferes with a cryptographic protocol by inserting ( a part of ) a message that has been sent previously in a protocol run

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.

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 ).

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

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.

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.

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.

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.

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 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.

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.