Stream ciphers

simple type of polyalphabetic encryption system

encryption technique utilizing a one-time pre-shared key at least as long as the encrypted message

In cryptography, RC4 (also known as ARC4 or ARCFOUR, meaning Alleged RC4, see below) 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 insecure protocols such as the obsolete WEP protocol historically used to secure WiFi networks.

symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream

DVD video copy-protection system

Salsa20 (formerly known as Snuffle 2005) and the closely related ChaCha are stream ciphers developed by Daniel J. Bernstein. Salsa20, the original cipher, was designed in 2005, then later submitted to the eSTREAM European Union cryptographic validation process by Bernstein. ChaCha is a modification of Salsa20 published in 2008. It uses a new round function that increases diffusion and increases performance on some architectures.

A5/1 is a stream cipher used to provide over-the-air communication privacy in the GSM cellular telephone standard. It is one of several implementations of the A5 security protocol. It was initially kept secret, but became public knowledge through leaks and reverse engineering. A number of serious weaknesses in the cipher have been identified.

American cryptographer (1890–1960)

encryption by simple exclusive-or logic operations

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.

type of cipher

cipher

In cryptography, a keystream is a stream of random or pseudorandom characters that are combined with a plaintext message to produce an encrypted message (the ciphertext).

stream cipher

cryptographic algorithm

A5/2 is a stream cipher used to provide voice privacy in the GSM cellular telephone protocol. It was designed in 1992-1993 (finished March 1993) as a replacement for the relatively stronger (but still weak) A5/1, to allow the GSM standard to be exported to countries "with restrictions on the import of products with cryptographic security features".

HC-256 is a stream cipher designed to provide bulk encryption in software at high speeds while permitting strong confidence in its security. A 128-bit variant was submitted as an eSTREAM cipher candidate and has been selected as one of the four final contestants in the software profile.

cipher

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.

In cryptography, Mutual Irregular Clocking KEYstream generator (MICKEY) is a stream cipher algorithm developed by Steve Babbage and Matthew Dodd. The cipher is designed to be used in hardware platforms with limited resources, and was one of the three ciphers accepted into Profile 2 of the eSTREAM portfolio. The algorithm is not patented and is free for any use.

cryptography primitive