Órdenes de la magnitud (longitud)
See also: Py
Py is an algorithm of Chiffrement by flood developed by Eli Biham and Jennifer Seberry.
It can manage keys a length being able to go to 256 bits. Intended to be an alternative surer and more powerful than RC4, Py was published in 2005 at the time of the contest ECrypt . The algorithm is based on a named structure of data rolling arrays , a term which symbolizes in fact an optimized circular table accompanied by an operation (addition or permutation). The key makes it possible to set up the structure interns made up of two tables, coding is thus conditioned by this internal state of 10400 bits.
A Vecteur of initialization of 128 bytes makes it possible to change the quantified sequence if the key is identical and that the data are the same ones. An iteration of the algorithm generates 8 bytes with which are carried out a XOR of the 8 bytes coming from the data to quantify. Py can treat messages a length maximum of 264 bits, a number sufficient for the near total of the applications. The management of messages longer would have required an additional cryptanalyse to make sure of the statistical uniformity exits.
Py theoretically is regarded as broken, indeed it exists a means of distinguishing its exit from a random flood. But the specifications of Py specify that its safety is guaranteed only so less 264 messages are considered in the structure, but these attacks have a larger complexity.
Anecdote
Py must be in fact written in Cyrillic letters: Ру , which is read: “Rou”. It is the termination of the English word kangaroo (“Kangourou”), Eli Biham having for tradition to name its algorithms according to animals. The algorithm having been conceived with Australian Jennifer Seberry, Biham thought directly of the Kangourou.
See too
- Solitary RC4
- (figure)
External bonds
- Specifications of the algorithm, codes out of C and cryptanalyse
- Cryptanalyse de Py