Portal:Cryptography

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Cryptography Wikiportal

Cryptography (from Greek κρύπτω, "to conceal, to obscure", and γράφω, "to etch, to inscribe, to write down") is, traditionally, the study of means of converting information from its normal, comprehensible form into an incomprehensible format, rendering it unreadable without secret knowledge — the art of encryption. Cryptography is often used to replace or in combination with steganography. In the past, cryptography helped ensure secrecy in important communications, such as those of spies, military leaders, and diplomats. In recent decades, the field of cryptography has expanded its remit in two ways. Firstly, it provides mechanisms for more than just keeping secrets: schemes like digital signatures and digital cash, for example. Secondly, cryptography has come to be in widespread use by many civilians who do not have extraordinary needs for secrecy, although typically it is transparently built into the infrastructure for computing and telecommunications, and users are not aware of it.

More about Cryptography...

Selected article

Cryptographically secure pseudo-random number generators are essential components in cryptography and they must ensure various security criteria such as resistance to corrupted sources or entropy loss. They are used during the generation process of new keys, random passwords, for initialization vectors, salting and other cryptographic primitives. Among these algorithms, one can find Blum Blum Shub, Fortuna or Yarrow.

Other featured articles: Caesar cipher — Cryptography — Data Encryption Standard — Enigma machine — ROT13 — Voynich manuscript

Selected picture edit

The EFF's US$250,000 DES cracking machine contained over 1,800 custom chips and could brute force a DES key in a matter of days — the photo shows a DES Cracker circuit board fitted with several Deep Crack chips] In cryptography, the EFF DES cracker (nicknamed "Deep Crack") is a machine built by the Electronic Frontier Foundation (EFF) to perform a brute force search of DES cipher's keyspace—that is, to decrypt an encrypted message by trying every possible key. The aim in doing this was to prove that DES's key is not long enough to be secure. edit

Did you know...

...that the Pigpen cipher was used by the Freemasons for correspondence and record keeping?
...that Polish mathematician Marian Rejewski (pictured) deduced the wiring of the German Enigma machine in 1932 using theorems about permutations?

...that acoustic cryptanalysis is a type of attack that exploits sound in order to compromise a system?
...that one scheme to defeat spam involves proving that the sender has performed a small amount of computation: a proof-of-work system?

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Miscellaneous

WikiProject Cryptography

Project digest for February 2005

Project digest for March 2005
WikiReader in Cryptography
Automatic link: Recent changes in articles about cryptography
Topics in cryptography — an annotated list of cryptography topics

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News

New Windows malware "Gpcode.AK" appears in early June 2008, using RC4-128 and RSA-1024 ciphers to take document files hostage for ransom.
RSA-640 was factored on November 2, 2005.
From 14 August 2005–18 August 2005 the 25th Annual International Cryptology Conference CRYPTO 2005 took place in Santa Barbara, California, USA. At the rump session, an improved collision attack on SHA-1 was announced.
RSA-200 was factored on 9 May 2005. At 663 bits (200 decimal digits), the number is the largest of the RSA numbers yet factored.
The US Secret Service is reported to be using 4,000 of its computers in a distributed dictionary attack to solve passwords used to protect encryption keys [1]. They report particular success in crafting custom dictionaries based on knowledge of a suspect's personal interests.
In Australia, the Vigenère cipher is being used to communicate with an extortionist via the advertisements in a newspaper [2].

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Thing you can do

Current tasks for Wikipedia:WikiProject Cryptography edit

Improvement to featured or good article status:

Alan Turing, anonymous remailer, digital signature, frequency analysis, grille (cryptography), one time pad, pretty good privacy, purple code, secret sharing, substitution cipher

Start from scratch:

- Theory: Computational boundedness, Lattice-based cryptography, Universal composability
- Hash functions: MDC-4, SMASH (hash)
- Historical cryptography: TELWA, Hut 3, Hut 4
  - Cipher machines: Alvis (cipher machine), SIGTOT, B-211 or B-21 (cryptography), OMI (machine), Siemens SFM T43, SA-1 (cryptography), BC-543, BC-38, Syko, CORAL, PENELOPE, RED (cipher machine)
- Stream ciphers: Correlation attack, Fast correlation attack, HBB (cipher)
- Block ciphers: Vino (cipher), BKSQ, Manta (cipher)
- Block cipher misc topics: RMAC, IAPM, XECB
- Block cipher cryptanalysis: Yoyo game
- Boolean functions and S-boxes: bent function
- Cryptographers: Joan Clarke, Francis Fasson, Vladimir Furman, Joos Vandewalle, Toshio Tokita, Henri Gilbert, Helena Handschuh, Antoon Bosselaers, Christophe De Cannière, Joseph Lano, Håvard Raddum, Michael Wiener
- Misc: Elementary cryptography