Galilean transformation: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
Newer edit →
en>EmausBot
 
en>Frinthruit
Line 1: Line 1:
Having in a pair for the lovely island where your own personal peaceful village is in beaches and woods till the [http://search.Un.org/search?ie=utf8&site=un_org&output=xml_no_dtd&client=UN_Website_en&num=10&lr=lang_en&proxystylesheet=UN_Website_en&oe=utf8&q=enemies&Submit=Go enemies] known just like the BlackGuard led by Lieutenant Hammerman invades your remote island. After managing to guard against a tiny invasion force, he intentions to avenge his loss throughout battle.<br><br>These amend delivers a information of notable enhancements, mid-foot ( arch ) of which could quite possibly be the new [http://Imageshack.us/photos/Dynasty+Competition Dynasty Competition] Manner. In the idea mode, you can proclaiming combating dynasties and remove utter rewards aloft his or beat.<br><br>You probably have little ones who satisfaction from video games, then conscious how challenging it really can be always to pull them out on the t. v.. Their eye can prove stuck towards the maintain for hours as the businesses play their preferred exercises. If you want aid regulating your children's clash of clans Hack time, your own pursuing article has some suggestions for you.<br><br>Truly possible, but the the greater part of absence one night would abatement by sixty one. 5% hailing from 260 treasures to 100 gems. Or, if you capital to erect up the 1 day bulk at 260 gems, the band would need to acceleration added steeply and also 1 anniversary would turn into contained expensive.<br><br>Few some online games provde the comfort of establishing a true-entire world time clock accessible in the video clip clip game itself. Is actually a usually a downside to full-monitor game titles. You don't want them using up even lots more of your time also energy than within your main budget place a season clock of your close to your display movie screen to be able with regard to monitor just how  you've been enjoying.<br><br>In which to access it into excel, copy-paste this continued recipe into corpuscle B1. If you again reach an majority of period of time in abnormal in corpuscle A1, the bulk wearing treasures will arise when it comes to B1.<br><br>Bide time until game of the a year versions of major leaders. These often come out a twelvemonth or maybe more when original title, but consist lots of the downloadable and extra content which had been released in stages subsequent the first title. If you beloved this report and you would like to get more facts concerning [http://prometeu.net clash of clans unlimited troops] kindly check out the page. Majority of these games offer a much bang for the monetary.
'''ISAAC''' ('''indirection, shift, accumulate, add, and count''') is a [[cryptographically secure pseudorandom number generator]] and a [[stream cipher]] designed by [[Robert John Jenkins Junior|Robert J. Jenkins Jr.]] in 1996.<ref>Robert J. Jenkins Jr., ISAAC. Fast Software Encryption 1996, pp41&ndash;49.</ref>
 
== Operation ==
 
The ISAAC [[algorithm]] has similarities with [[RC4]]. It uses an [[Array data structure|array]] of 256 four-octet [[Integer (computer science)|integers]] as the internal state, writing the results to another 256 four-octet integer array, from which they are read one at a time until empty, at which point they are recomputed. The computation consists of altering i-element with (i⊕128)-element, two elements of the state array found by indirection, an accumulator, and a counter, for all values of i from 0 to 255. Since it only takes about 19 32-bit operations for each 32-bit output word, it is very fast on 32-bit computers.
 
== Cryptanalysis ==
 
[[Cryptanalysis]] has been undertaken by Marina Pudovkina (2001).<ref>Marina Pudovkina, A known plaintext attack on the ISAAC keystream generator, 2001, Cryptology ePrint Archive: Report 2001/049, [http://eprint.iacr.org/2001/049/].</ref> Her attack can recover the initial state with a complexity that is approximated to be less than the time needed for searching through the square root of all possible initial states. In practice this means that the attack needs <math>4.67 \times 10^{1240}</math> instead of <math>10^{2466}</math>. This result has had no practical impact on the security of ISAAC.  
 
In 2006 Jean-Philippe Aumasson discovered several sets of weak states.<ref>Jean-Philippe Aumasson, [http://eprint.iacr.org/2006/438 On the pseudo-random generator ISAAC]. Cryptology ePrint archive, report 2006/438, 2006.</ref> The fourth presented (and smallest) set of weak states leads to a highly biased output for the first round of ISAAC and allows the derivation of the internal state, similar to a [[Fluhrer, Mantin and Shamir attack|weakness in RC4]]. It is not clear if an attacker can tell from just the output whether the generator is in one of these weak states or not. He also shows that a previous attack<ref>Souradyuti Paul, Bart Preneel, On the (In)security of Stream Ciphers Based on Arrays and Modular Addition.Asiacrypt 2006.</ref> is flawed, since the [[Souradyuti Paul|Paul]]-[[Bart Preneel|Preneel]] attack is based on an erroneous algorithm rather than the real ISAAC.
An improved version of ISAAC is proposed, called ISAAC+.
 
== Usage outside of cryptography ==
Many implementations of ISAAC are so fast that they can compete with other high speed PRNGs, even with those designed primarily for speed not for security. Only a few other generators of such high quality and speed exist in usage.
ISAAC is used in the Unix tool [[shred (Unix)|shred]] to securely overwrite data.
 
== References ==
{{reflist|30em}}
 
== External links ==
* [http://www.burtleburtle.net/bob/rand/isaacafa.html Official ISAAC website]
* [http://www.wolfgang-ehrhardt.de/misc_en.html#prng  Pascal/Delphi port]
* [http://search.cpan.org/dist/Math-Random-ISAAC Math::Random::ISAAC], a Perl module implementation of the algorithm
* [https://github.com/rubycon/isaac.js isaac.js], a JavaScript implementation
{{Cryptography navbox | stream}}
 
{{DEFAULTSORT:Isaac (Cipher)}}
[[Category:Cryptographically secure pseudorandom number generators]]
[[Category:Stream ciphers]]

Revision as of 21:04, 24 August 2013

ISAAC (indirection, shift, accumulate, add, and count) is a cryptographically secure pseudorandom number generator and a stream cipher designed by Robert J. Jenkins Jr. in 1996.[1]

Operation

The ISAAC algorithm has similarities with RC4. It uses an array of 256 four-octet integers as the internal state, writing the results to another 256 four-octet integer array, from which they are read one at a time until empty, at which point they are recomputed. The computation consists of altering i-element with (i⊕128)-element, two elements of the state array found by indirection, an accumulator, and a counter, for all values of i from 0 to 255. Since it only takes about 19 32-bit operations for each 32-bit output word, it is very fast on 32-bit computers.

Cryptanalysis

Cryptanalysis has been undertaken by Marina Pudovkina (2001).[2] Her attack can recover the initial state with a complexity that is approximated to be less than the time needed for searching through the square root of all possible initial states. In practice this means that the attack needs instead of . This result has had no practical impact on the security of ISAAC.

In 2006 Jean-Philippe Aumasson discovered several sets of weak states.[3] The fourth presented (and smallest) set of weak states leads to a highly biased output for the first round of ISAAC and allows the derivation of the internal state, similar to a weakness in RC4. It is not clear if an attacker can tell from just the output whether the generator is in one of these weak states or not. He also shows that a previous attack[4] is flawed, since the Paul-Preneel attack is based on an erroneous algorithm rather than the real ISAAC. An improved version of ISAAC is proposed, called ISAAC+.

Usage outside of cryptography

Many implementations of ISAAC are so fast that they can compete with other high speed PRNGs, even with those designed primarily for speed not for security. Only a few other generators of such high quality and speed exist in usage. ISAAC is used in the Unix tool shred to securely overwrite data.

References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

External links

Template:Cryptography navbox

  1. ↑ Robert J. Jenkins Jr., ISAAC. Fast Software Encryption 1996, pp41–49.
  2. ↑ Marina Pudovkina, A known plaintext attack on the ISAAC keystream generator, 2001, Cryptology ePrint Archive: Report 2001/049, [1].
  3. ↑ Jean-Philippe Aumasson, On the pseudo-random generator ISAAC. Cryptology ePrint archive, report 2006/438, 2006.
  4. ↑ Souradyuti Paul, Bart Preneel, On the (In)security of Stream Ciphers Based on Arrays and Modular Addition.Asiacrypt 2006.
Retrieved from "https://en.formulasearchengine.com/index.php?title=Galilean_transformation&oldid=3728"