In cryptography, RC4 is a stream cipher. While it is remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure. It is especially vulnerable when the beginning of the output keystream is not discarded, or when nonrandom or related keys are used. Particularly problematic uses of RC4 have led to very insecure protocols such as WEP.
A pseudorandom number generator (PRNG), also known as a deterministic random bit generator (DRBG), is an algorithm for generating a sequence of numbers whose properties approximate the properties of sequences of random numbers. The PRNG-generated sequence is not truly random, because it is completely determined by an initial value, called the PRNG's seed. Although sequences that are closer to truly random can be generated using hardware random number generators, pseudorandom number generators are important in practice for their speed in number generation and their reproducibility.
The Mersenne Twister is a general-purpose pseudorandom number generator (PRNG) developed in 1997 by Makoto Matsumoto and Takuji Nishimura. Its name derives from the choice of a Mersenne prime as its period length.
A Lagged Fibonacci generator is an example of a pseudorandom number generator. This class of random number generator is aimed at being an improvement on the 'standard' linear congruential generator. These are based on a generalisation of the Fibonacci sequence.
mcrypt is a replacement for the popular Unix crypt command. crypt was a file encryption tool that used an algorithm very close to the World War II Enigma cipher. Mcrypt provides the same functionality but uses several modern algorithms such as AES. Libmcrypt, Mcrypt's companion, is a library of code that contains the actual encryption functions and provides an easy method for use. The last update to libmcrypt was in 2007, despite years of unmerged patches. Maintained alternatives include ccrypt, libressl, and others.
eSTREAM is a project to "identify new stream ciphers suitable for widespread adoption", organised by the EU ECRYPT network. It was set up as a result of the failure of all six stream ciphers submitted to the NESSIE project. The call for primitives was first issued in November 2004. The project was completed in April 2008. The project was divided into separate phases and the project goal was to find algorithms suitable for different application profiles.
Grain is a stream cipher submitted to eSTREAM in 2004 by Martin Hell, Thomas Johansson and Willi Meier. It has been selected for the final eSTREAM portfolio for Profile 2 by the eSTREAM project. Grain is designed primarily for restricted hardware environments. It accepts an 80-bit key and a 64-bit IV. The specifications do not recommend a maximum length of output per pair. A number of potential weaknesses in the cipher have been identified and corrected in Grain 128a which is now the recommended cipher to use for hardware environments providing both 128bit security and authentication.
CrypTool is an open-source project that is a free e-learning software for illustrating cryptographic and cryptanalytic concepts. According to "Hakin9", CrypTool is worldwide the most widespread e-learning software in the field of cryptology.
Disk encryption is a special case of data at rest protection when the storage medium is a sector-addressable device. This article presents cryptographic aspects of the problem. For an overview, see disk encryption. For discussion of different software packages and hardware devices devoted to this problem, see disk encryption software and disk encryption hardware.
The American Cryptogram Association (ACA) is an American non-profit organization devoted to the hobby of cryptography, with an emphasis on types of codes, ciphers, and cryptograms that can be solved either with pencil and paper, or with computers, but not computer-only systems.
Sosemanuk is a stream cipher developed by Come Berbain, Olivier Billet, Anne Canteaut, Nicolas Courtois, Henri Gilbert, Louis Goubin, Aline Gouget, Louis Granboulan, Cédric Lauradoux, Marine Minier, Thomas Pornin and Hervé Sibert. Along with HC-128, Rabbit, and Salsa20/12, Sosemanuk is one of the final four Profile 1 (software) ciphers selected for the eSTREAM Portfolio.
Rabbit is a high-speed stream cipher from 2003. The algorithm and source code was released in 2008 as public domain software.
FreeOTFE is a discontinued open source computer program for on-the-fly disk encryption (OTFE). On Microsoft Windows, and Windows Mobile, it can create a virtual drive within a file or partition, to which anything written is automatically encrypted before being stored on a computer's hard or USB drive. It is similar in function to other disk encryption programs including TrueCrypt and Microsoft's BitLocker.
In cryptography, Achterbahn is the name of a synchronous stream cipher algorithm submitted to the eSTREAM Project of the eCRYPT network. In the final specification the cipher is called ACHTERBAHN-128/80, because it supports the key lengths of 80 bits and 128 bits, respectively. Achterbahn was developed by Berndt Gammel, Rainer Göttfert and Oliver Kniffler. Achterbahn means rollercoaster, though a literal translation of the term would be eight-track, which indicates that the cipher can encrypt eight bit streams in parallel.
In cryptography, Hermes8 is the name of a stream cypher algorithm designed by Ulrich Kaiser. It has been submitted to the eSTREAM Project of the eCRYPT network. It has been classified as an 'archive' algorithm and will not be further considered.
dm-crypt is a transparent block device encryption subsystem in Linux kernel versions 2.6 and later and in DragonFly BSD. It is part of the device mapper (dm) infrastructure, and uses cryptographic routines from the kernel's Crypto API. Unlike its predecessor cryptoloop, dm-crypt was designed to support advanced modes of operation, such as XTS, LRW and ESSIV, in order to avoid watermarking attacks. In addition to that, dm-crypt addresses some reliability problems of cryptoloop.
A time/memory/data tradeoff attack is a type of cryptographic attack where an attacker tries to achieve a situation similar to the space–time tradeoff but with the additional parameter of data, representing the amount of data available to the attacker. An attacker balances or reduces one or two of those parameters in favor of the other one or two. This type of attack is very difficult, so most of the ciphers and encryption schemes in use were not designed to resist it.
A counter-based random number generation is a kind of pseudorandom number generator that uses only an integer counter as its internal state. They are generally used for generating pseudorandom numbers for large parallel computations.
