Cryptography Portal
Cryptography (from Greek κρύπτω, "to hide, 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 infrastructurefor computing and telecommunications, and users are not aware of it.
Selected article
The Enigma machine was a portable cipher machine used to encrypt and decrypt secret messages. More precisely, Enigma was a family of related electro-mechanical rotor machines — there are a variety of different models.The Enigma was used commercially from the early 1920s on, and was also adopted by military and governmental services of a number of nations — most famously, by Nazi Germany before and during World War II. The German military model, the WehrmachtEnigma, is the version most commonly discussed.Allied codebreakers were, in many cases, able todecrypt messages protected by the machine (seecryptanalysis of the Enigma). The intelligencegained through this source — codenamed ULTRA— was a significant aid to the Allied war effort. Some historians have suggested that the end of the European war was hastened by up to a year or more because of the decryption of German ciphers.
Selected picture
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.
Did you know...
...that the Pigpen cipher was used by theFreemasons 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 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 exploitssound 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?
...that one scheme to defeat spam involves proving that the sender has performed a small amount of computation: a proof-of-work system?
Miscellaneous
- WikiProject Cryptography
- WikiReader in Cryptography
- Automatic link: Recent changes in articles about cryptography
- Topics in cryptography — an annotated list of cryptography topics
Categories
News
- Karsten Nohl, chief research scientist with H4RDW4RE, announces that by the end of the year he will break the A5/1 system used in the GSM phone system.[1]
- New Windows malware "Gpcode.AK" appears in early June 2008, using RC4-128 and RSA-1024 ciphers to take document files hostage for ransom.
Things you can do
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