DFC (cipher)

In cryptography, DFC (Decorrelated Fast Cipher) is a symmetric block cipher which was created in 1998 by a group of researchers from École Normale Supérieure, CNRS, and France Télécom (including Jacques Stern and Serge Vaudenay) and submitted to the AES competition.

Like other AES candidates, DFC operates on blocks of 128 bits, using a key of 128, 192, or 256 bits. It uses an 8-round Feistel network. The round function uses a single 6×32-bit S-box, as well as an affine transformation mod 2⁶⁴+13. DFC can actually use a key of any size up to 256 bits; the key schedule uses another 4-round Feistel network to generate a 1024-bit "expanded key". The arbitrary constants, including all entries of the S-box, are derived using the binary expansion of e as a source of "nothing up my sleeve numbers".

Soon after DFC's publication, Ian Harvey raised the concern that reduction modulo a 65-bit number was beyond the native capabilities of most platforms, and that careful implementation would be required to protect against side-channel attacks, especially timing attacks. Although DFC was designed using Vaudenay's decorrelation theory to be provably secure against ordinary differential and linear cryptanalysis, in 1999 Lars Knudsen and Vincent Rijmen presented a differential chosen-ciphertext attack that breaks 6 rounds faster than exhaustive search.

Cipher

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. An alternative, less common term is encipherment. To encipher or encode is to convert information into cipher or code. In common parlance, 'cipher' is synonymous with 'code', as they are both a set of steps that encrypt a message; however, the concepts are distinct in cryptography, especially classical cryptography.

Codes generally substitute different length strings of characters in the output, while ciphers generally substitute the same number of characters as are input. There are exceptions and some cipher systems may use slightly more, or fewer, characters when output versus the number that were input.

Codes operated by substituting according to a large codebook which linked a random string of characters or numbers to a word or phrase. For example, "UQJHSE" could be the code for "Proceed to the following coordinates." When using a cipher the original information is known as plaintext, and the encrypted form as ciphertext. The ciphertext message contains all the information of the plaintext message, but is not in a format readable by a human or computer without the proper mechanism to decrypt it.

Cipher (disambiguation)

A cipher is a method of encryption or decryption.

Cipher may also refer to:

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Cipher (newuniversal)

Cipher (Jennifer Swann) is a fictional character appearing in American comic books published by Marvel Comics. The character appears in the newuniversal imprint of Marvel Comics, and is one of the four initial superhumans created by the White Event in 2006 (the others being Justice, Nightmask, and Star Brand). newuniversal, designated Earth-555 in the Marvel Comics multiverse, is a re-imagining of the New Universe imprint from the late 1980s. The name Cipher actually refers to two things: a powerful extra-dimensional glyph (tattoo) that confers superhuman powers on a sentient being, and the name of the being that wields the glyph. Cipher is a new superhuman created by Warren Ellis and Salvador Larroca who were inspired by the original Spitfire and the nature of the Star Brand itself (as an extra-dimensional tool of near-unlimited power), combined with strong conceptual ties to Iron Man.

Fictional character biography

Project Spitfire

Essentially nothing is known about Dr. Jennifer Swann’s early life, or where she earned her doctorate. Sometime in the late 1990s or early 2000s she was hired by the NSA to work on Project Spitfire, taking her father’s previous position there. Jennifer continues the work her father, Dr. Joseph Swann, began in 1959 on the H.E.X. (Human Enhancement eXperimental) initiative, an armored exoskeleton that is intended to enable its wearer to combat superhumans with a wide variety of weapons. The original suit was created by Anthony Stark in 1959 who became Cipher in the "The Fireworks" event in 1955, and is an alternate version of Tony Stark (Iron Man) from the mainstream Marvel Universe. Prior to the events in newuniversal #1, neither Jennifer nor her father were able to perfect the design, both suffering broken bones during testing.

DFC

DFC may refer to:

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Distinguished Flying Cross (United Kingdom)

The Distinguished Flying Cross is the third-level military decoration awarded to personnel of the United Kingdom's Royal Air Force and other services, and formerly to officers of other Commonwealth countries, instituted for "an act or acts of valour, courage or devotion to duty whilst flying in active operations against the enemy".

History

The award was established on 3 June 1918, shortly after the formation of the RAF. It was originally awarded to Royal Air Force commissioned and warrant officers. During World War II it was awarded to Royal Artillery officers serving on attachment to the RAF as pilots-cum-artillery observers. Since World War II, the award has been open to army and naval aviation officers, and since 1993 to other ranks; the Distinguished Flying Medal, awarded to other ranks, has been discontinued. Recipients of the Distinguished Flying Cross are entitled to use the post-nominal letters "DFC". A bar is added to the ribbon for holders of the DFC who received a second award.

DFC (group)

DFC was an American hip hop duo composed of Flint, Michigan natives Alpha "Al" Breed and Bobby "T-Dub" Thompson. They were closely associated with MC Breed who was also Al's cousin.

DFC stands for Da Funk Clan.

MC Breed and DFC released their collaborative debut album on November 11, 1991 entitled MC Breed & DFC, which charted at 142 on the Billboard 200 and featured their most successful single, "Ain't No Future in Yo' Frontin'".

After MC Breed & DFC, DFC signed with Atlantic Records and were placed on their subsidiary Big Beat Records. They then released 1994's Things in tha Hood which became their most successful album, peaking at 71 on the Billboard 200 and spawning the singles "Caps Get Peeled" and "Thing in tha Hood". They followed up with 1997's The Whole World's Rotten, but disbanded in 1999 after appearing on MC Breed's It's All Good.

Discography

Albums

Singles

References