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Topic: Permutation cipher


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In the News (Thu 26 Nov 09)

  
  Transposition cipher - Wikipedia, the free encyclopedia
In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done).
Both the length of the rows and the permutation of the columns are usually defined by a keyword.
Until the discovery of the VIC cipher, double transposition was generally regarded as the most complicated cipher that an agent could operate reliably under difficult field conditions.
en.wikipedia.org /wiki/Transposition_cipher   (1469 words)

  
 Permutation cipher - Wikipedia, the free encyclopedia
In classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation.
To apply a cipher, a random permutation of size e is generated (the larger the value of e the more secure the cipher).
In theory, any transposition cipher can be viewed as a permutation cipher where e is equal to the length of the plaintext; this is too cumbersome a generalisation to use in actual practice, however.
en.wikipedia.org /wiki/Permutation_cipher   (321 words)

  
 United States Patent 5,727,062
A chaining mode is not a block cipher in the sense of the present application, and the '152 patent does not handle the variable size block ciphers of the present application.
All ciphers are made from smaller components, and many block ciphers have operations in layers of some form or other, but it is unusual to find a block cipher design in which each layer can be easily extended (in element-size steps) to arbitrary size.
In the context of a variable size block cipher, an element is the width of a single column or ciphering unit, often a byte.
www.ciphersbyritter.com /PATS/VSBCPAT.HTM   (15792 words)

  
 Permutation cipher -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-21)
In classical (Act of writing in code or cipher) cryptography, a permutation cipher is a (Click link for more info and facts about transposition cipher) transposition cipher in which the (A lever that actuates a mechanism when depressed) key is a (Act of changing the lineal order of objects in a group) permutation.
To apply a cipher, a (Click link for more info and facts about random) random permutation of size e is generated (the larger the value of e the more secure the cipher).
Trying to find this permutation is essentially the same problem encountered when analysing a columnar transposition cipher: multiple (Click link for more info and facts about anagramming) anagramming.
www.absoluteastronomy.com /encyclopedia/p/pe/permutation_cipher.htm   (399 words)

  
 FIRST ADVANCED ENCRYPTION STANDARD (AES) CANDIDATE CONFERENCE
This permutation uses addition modulo 2^64 and the XOR operation with two fixed constants and another constant that is chosen from a table according to six of the data bits.
The permutation is a linear transformation of data bytes; each keyed substitution consists of key XOR followed by the application of an 8x8 s-box to each byte.
MARS is a cipher with thirty-two modified Feistel rounds structured as follows: key addition, eight rounds of "unkeyed forward mixing," eight rounds of "keyed forward transformation," eight rounds of "keyed backwards transformation," eight rounds of "unkeyed backwards mixing," and key subtraction.
www.ieee-security.org /Cipher/ConfReports/conf-rep-aes.html   (5942 words)

  
 [jsword-svn] common/java/core/org/crosswire/common/crypt s
Four of * the bytes in the permutation vector are moved to new locations (which may be * the same as the old location) for every byte output.
The output byte is a * nonlinear function of all 5 of the index values and 8 of the bytes in the * permutation vector, thus frustrating attempts to solve for the state * variables based on past output.
Solving for the * contents of the permutation vector by keeping track of the possible positions * of the index variables and possible contents of the permutation vector at * each byte position is not possible, since more variables than known values * are generated at each iteration.
www.crosswire.org /pipermail/jsword-svn/2005-March/000258.html   (2727 words)

  
 The Dynamic Transposition Combiner
These ciphers permute plaintext into ciphertext by swapping every message element with some message element selected at pseudo-random; elements can be characters (e.g., bytes) or bits.
Permutation has been used for entire ciphers (mainly in an era of pencil-and-paper operations), and, in a limited form, is still in common use inside substitution-permutation networks [11] of the sort from which the U.S. Data Encryption Standard [e.g., 21] is built.
A simple cipher module like this actually may be much more valuable than a complex one, for it may eventually be possible to understand its exact limitations, and then answer those limitations completely in other modules.
www.ciphersbyritter.com /ARTS/DYNTRAN2.HTM   (6039 words)

  
 Block Ciphers
Block ciphers are the most basic, as they use a single key to transform a block of text with a specific length.
Block ciphers can be adapted to work as stream ciphers, which ensure that each block is dependant on previous blocks in the ciphertext (see Section 3.2 for more details on stream ciphers).
Another improvement is that the initial and final permutations could be replaced with a function that is co-dependant on the key and the text.
www.cs.usask.ca /~dtr467/400   (6127 words)

  
 [No title]   (Site not responding. Last check: 2007-10-21)
Four of the bytes in the permutation vector are moved to new locations (which may be the same as the old location) for every byte output.
The output byte is a nonlinear function of all 5 of the index values and 8 of the bytes in the permutation vector, thus frustrating attempts to solve for the state variables based on past output.
The index variables are set (somewhat arbitrarily) to the permutation vector elements at locations 1, 3, 5, 7, and a key dependent value (rsum) left over from the shuffling of the permutation vector (cards array).
web.textfiles.com /software/sapphire.txt   (2217 words)

  
 VMPC One-Way Function and Stream Cipher   (Site not responding. Last check: 2007-10-21)
Analysis of cycle lengths for scaled-down variants of the VMPC Stream Cipher suggests that probability of entering a short cycle by the Cipher is approximately in line with a random permutation model, e.g.
To compare cycle lengths in the output of the VMPC Stream Cipher to a random permutation, the Cipher was scaled-down to use N element internal permutations, for N from 4 to 10.
The total number of possible states of the cipher is determined by all possible configurations of the internal permutation P and variables s and n and is equal N! Cycles of the following lengths occur for the scaled-down-to-N variants of the Cipher:
www.vmpcfunction.com /c12.htm   (322 words)

  
 Dynamic Transposition Ciphering
Cipher users thus find themselves in the position of continually betting that nobody is that smart.
Ciphers are instead attacked and broken by finding some pattern which will discard huge numbers of possible keys with every test.
Note that conventional block ciphers have the first advantage only to a lesser extent, and the second advantage not at all, which is why they need "modes of operation." Known-plaintext attacks would be a first step in an attempt to attack the RNG as in a stream cipher.
www.ciphersbyritter.com /NEWS5/REDYNTRN.HTM   (18360 words)

  
 [No title]   (Site not responding. Last check: 2007-10-21)
Note that part (b) is asking you to cryptanalyze - you must determine the size of the block and the size of matrix by trial and error.
Using a linear feedback stream cipher with m=4, a key c = (1, 0, 0, 1) and k=(1, 1, 1, 1), encrypt the plaintext 10101110 and decrypt the ciphertext 11010111.
Problem 1.29 discusses a stream cipher like the Vigenere cipher, but with a key that rotates with each use.
www.cs.du.edu /~ftl/courses/3704w03/hw4.html   (384 words)

  
 [No title]
HPC HPC (Hasty Pudding Cipher) is a set of five subciphers, each covering a range of possible block sizes; the "medium" cipher applies to the 128 bit blocks mandated for the AES.
MARS MARS is a cipher with thirty-two modified Feistel rounds structured as follows: key addition, eight rounds of "unkeyed forward mixing," eight rounds of "keyed forward transformation," eight rounds of "keyed backwards transformation," eight rounds of "unkeyed backwards mixing," and key subtraction.
RC6^TM RC6^TM is a parameterized family of encryption ciphers that use a modified Feistel structure; under the parameters given for the AES submission, there are twenty rounds.
www.ieee-security.org /Cipher/PastIssues/1998/issue9812/issue9812.txt   (18815 words)

  
 Math 167: Game Theory   (Site not responding. Last check: 2007-10-21)
The lcm is 8 which is the order of the shuffle permutation.
A message is encrypted using a transposition (permutation) cipher of block length 4.
Solution: if you use the permutation (13)(24) on each 4 block you will get, with spaces added "we may never know who killed marilyn monroe".
www.math.ucla.edu /~blasius/197.1.02s/pmt1solutions.htm   (544 words)

  
 A Weak Cipher that Generates the Symmetric Group - Murphy, Paterson, Wild (ResearchIndex)   (Site not responding. Last check: 2007-10-21)
In this paper we present a cautionary example of a block cipher which generates the full symmetric group yet is very weak.
1 Introduction We consider iterated block ciphers in which each round of a block cipher is a permutation of the message space determined by the subkey used in that round.
Murphy, K. Paterson and P. Wild, `A Weak Cipher that Generates the Symmetric Group', Journal of Cryptology Vol.
citeseer.ist.psu.edu /89855.html   (386 words)

  
 [No title]   (Site not responding. Last check: 2007-10-21)
Permutation Cipher = Hill Cipher, where the key is a permutation matrix.
Both ciphers are insecure.ó#Ÿ¨Perfect SecrecyŸ A cryptosystem is computationally secure if the best algorithm for breaking it requires at least N operations, where N is some specified , very large number. Problems& A cryptosystem is unconditionally secure if it cannot be broken with infinite computational resources.¡d9D>ó$Ÿ¨Perfect SecrecyªŸ¨óNone of the classical cryptosystems is even computationally secure.
Suppose the 26 keys in the Shift Cipher are used with equal probability 1/26.
www2.semo.edu /jwojdylo/Research/cryptoclassic.ppt   (707 words)

  
 L13.html
The key is the rule telling which letter (or byte) to change into another letter (or byte).
A permutation cipher changes the order of the bytes.
The key is the permutation which describes the new order.
www.math.sfu.ca /~gfee/Math342/L131.html   (454 words)

  
 [No title]   (Site not responding. Last check: 2007-10-21)
Shift cipher Substitution cipher Affine Cipher key space allowable parameters solving congruence equations Vigenere Cipher the method effect on frequency distribution of characters size of keyspace Hill Cipher linear algebra in Zm identity marix, inverse of a matrix when is a matrix non-singular in Zm?
16, Stinson) effect on frequency distribution of characters Permutation Cipher (the matrix K is a permutation matrix) Stream Cipher keystream generator keystream defined by a linear recurrence periodicity of a keystream linear feedback shift register
Substitution Cipher using the statistical characteristics of English attempts to eliminate the above weakness homophonic ciphers the Beale Cipher polyalphabetic ciphers Alberti's Wheel (a precursor to the German Enigma machine) Vigenere Cipher What is the key length?
www.cs.umbc.edu /~stephens/crypto/EXAM/etopics.html   (410 words)

  
 Practice Problems   (Site not responding. Last check: 2007-10-21)
11 for Shift cipher how will the folowing texts be encrypted (Do all the steps).
What are the number of possible keywords of lengths m in Vigenere cipher?
What is cipher text corresponding to Plain text "shesellsseashellsbytheseashore".
netlab.cs.iitm.ernet.in /cs650/ex1.html   (87 words)

  
 [No title]
When you hit A, cycle around to Z until you hit the original character in the given cipher text.
It appears that there may be a flaw in the protocol used to devise the key to this cipher.
It was the correct assumption of the tri-graph-‘AND’ that led to the ciphers solution.
pegasus.cc.ucf.edu /~crypto/downloads/09242003/Solutions.doc   (837 words)

  
 exam1   (Site not responding. Last check: 2007-10-21)
The Hill cipher is a special case of the permutation cipher.
Iterating an idempotent cipher does not increase the level of security offered.
Suggest a way of determining whether the ciphertext was produced by a monoalphabetic cipher.
www.cs.ecu.edu /~gopal/crypt/exam1/exam1.html   (422 words)

  
 List of cryptography topics - LearnThis.Info Enclyclopedia   (Site not responding. Last check: 2007-10-21)
Babington plot -- Baby-step giant-step -- Bazeries cylinder -- Beale ciphers -- Bernstein v.
FEAL -- Feistel cipher -- Financial cryptography -- FISH (cryptography) -- Fortezza -- Frank A. Stevenson -- Frank Rowlett -- FreeLIP -- Frequency analysis -- Friedrich Kasiski -- Fritz-chip --
VENONA project -- VIC cipher -- Vigenère -- Vincent Rijmen -- Visual cryptography -- Voynich Manuscript --
encyclopedia.learnthis.info /l/li/list_of_cryptography_topics.html   (581 words)

  
 Encryption   (Site not responding. Last check: 2007-10-21)
Simple (monoalphabetic) cipher Ek(P)= P+b mod N (where N is size of alphabet) and P is an integer representing a unit of the plaintext (substitution cipher).
just represent a permutation of some block to guide you eg.(3 1 2 0)
b, or number in rows or the permutation
ca80.lehman.cuny.edu /bob/Fall01/Security/Encryption.html   (143 words)

  
 [No title]   (Site not responding. Last check: 2007-10-21)
/* This is a program for the block cipher Substitution Permutation Networks [SPN].
This is targeted to perform linear and differential cryptanalyses.
2) Different S-boxes and the permutation functions can be plugged in (not at run-time).
www.cs.rit.edu /~gxs5626/spn.c   (273 words)

  
 CS588: Problem Set 3   (Site not responding. Last check: 2007-10-21)
Same as PS2, except for this assignment you may not work with the same person with whom you worked on PS2.
Problem Set 1 close to correctly, it seems appropriate to have another question on the permutation cipher.
Justify your answer by describing the elements of your message set, and why it is not possible to transmit any larger set of possible message without revealing some potentially useful information to a passive attacker.
www.cs.virginia.edu /~evans/cs588/ps/ps3   (600 words)

  
 [20040901] CRYPTOGRAPHY: THEORY AND PRACTICE 2ND EDITION
Now more tightly focused on the core areas, it contains many new topics as well as thoroughly updated treatments of topics presented in the first edition.
Cryptanalysis of the Affine Cipher Cryptanalysis of the Substitution Cipher Cryptanalysis of the Vigenère Cipher Cryptanalysis of the Hill Cipher Cryptanalysis of the LFSR Stream Cipher Exercises
BLOCK CIPHERS AND THE ADVANCED ENCRYPTION STANDARD Introduction
noise.ticmundi.com /1-58488-206-9.html   (468 words)

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