21. Libketama - A Consistent Hashing Algo For Memcache Clients – RJ’s Jour Ketama is an implementation of a consistent hashing algorithm, meaning you can add or remove servers from the memcached pool without causing a complete http://www.last.fm/user/RJ/journal/2007/04/10/392555/

Music Users Listen Events ... Log in or Sign up Upload music and videos Help English RJ Overview Charts Journal Groups ... Tags Loading… RJ’s Journal libketama - a consistent hashing algo for memcache clients libketama - a consistent hashing algo for memcache clients 10 Apr 2007, 17:36 server = serverlist[hash(key)%serverlist.length]; This meant that whenever we added or removed servers from the pool, everything hashed to different servers, which effectively wiped the entire cache. We add (and sometimes remove) servers from the memcached pool often enough to warrant writing this - if your memcached pool never changes, you can probably stop reading now :) Ketama is an implementation of a consistent hashing algorithm, meaning you can add or remove servers from the memcached pool without causing a complete remap of all keys. Here's how it works: * Take your list of servers (eg: 1.2.3.4:11211, 5.6.7.8:11211, 9.8.7.6:11211) * Hash each server string to several (100-200) unsigned ints * Conceptually, these numbers are placed on a circle called the continuum. (imagine a clock face that goes from to 2^32) * Each number links to the server it was hashed from, so servers appear at several points on the continuum, by each of the numbers they hashed to.

22. Portable PHP Password Hashing Framework A portable public domain password hashing framework for use in PHP applications. Tested with PHP 3, 4, and 5. http://www.openwall.com/phpass/

Openwall Project /home Owl JtR ... CVSweb bringing security into open environments Order Openwall GNU/*/Linux 2.0 on a CD with delivery worldwide Portable PHP password hashing framework Please note that password hashing is often wrongly referred to as "password encryption". Hashing is a more appropriate term since encryption is something that is supposed to be easily reversible. This is a portable public domain password hashing framework for use in PHP applications. It is meant to work with PHP 3 and above, and it has actually been tested with at least PHP 3.0.18, 4.3.x, 4.4.x, 5.0.x, 5.1.x, and 5.2.x so far. The preferred (most secure) hashing method supported by phpass is the OpenBSD-style Blowfish-based bcrypt , also supported with our public domain package (for C applications), and known in PHP as CRYPT_BLOWFISH, with a fallback to BSDI-style extended DES-based hashes, known in PHP as CRYPT_EXT_DES, and a last resort fallback to MD5-based salted and variable iteration count password hashes implemented in phpass itself (also referred to as portable hashes). To ensure that the fallbacks will never occur, the

23. How To: Hash Data With Salt (C#/VB.NET) Sample Code hashing data in C .NET and VB.NET using MD5, SHA1, SHA256, SHA384, and SHA512 algoritnms. http://www.obviex.com/samples/hash.aspx

Home Buy Support Products ... Site Map How To: Hash Data with Salt (C#/VB.NET) The code below demonstrates how to hash data and verify hashes. It supports MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashing algorithms. To help reduce the risk of dictionary attacks, the code appends random bytes (so-called "salt") to the original plain text before generating hashes. Please keep in mind that salt can only help against prebuilt dictionaries. If an intruder gets access to your system and uses a brute force attack, salt will not provide much value. Code samples are provided in C# and Visual Basic.NET . IMPORTANT: DATA HASHES CANNOT BE "DECRYPTED" BACK TO PLAIN TEXT. Notes These examples are offered for demonstration purpose only. In a real application you may need to modify the code to make it more efficient. For example, instead of appending salt values to generated hashes, you may want to store them separately. Another performance improvement can be achieved by not converting results into base64-encoded strings, but manipulating them in a byte array format. For additional information about hashing, check MSDN sample describing how to use password hashes stored in a database for user authentication. See also the

24. Hash Table Applet This is a Java application that lets you experiment and compare exponential and double hashing on clustered data. You can input a cluster size between 1% http://www.jea.acm.org/CODE/Vol2Nbr3/hash.html

Hash Table Applet This is a Java application that lets you experiment and compare exponential and double hashing on clustered data. You can input a cluster size between 1% and 100%, and a table size between 100 and 10,000 elements. Press the run button to create two hash tables (one for exponential hashing and one for double hashing) and fill each to 95% capacity. The graph and output window will show the total number of probes required to fill the table to 95% of capacity. You need a Java capable browser to view this Java applet! Java Source Code: hash.java and HashTable.java and MyGraph.java C Source Code: hash.c and util.c and util.h

25. Hashing InChIs The InChI team has announced a proposal for a standardized InChI hashing mechanism. This would create a free, fixedlength, alphanumeric molecular http://depth-first.com/articles/2007/05/09/hashing-inchis

Hashing InChIs Posted by Rich Apodaca Wed, 09 May 2007 18:01:00 GMT The InChI team has announced a proposal for a standardized InChI hashing mechanism. This would create a free, fixed-length, alphanumeric molecular identifier. This is an excellent proposal. One of the biggest problems in working with InChIs (and other line notations such as SMILES) is that even medium-sized molecules produce very long identifiers. Another problem is the use of characters that must be escaped in URLs. The hashing proposal addresses both of these issues, getting very close to creating the optimal molecular identifier For example, imagine the convenience of being able to refer to a molecule by a universally-recognized, machine-generated string like the one shown below: AAAAAAAAAAA-BBBBBBB-XYZ This is something that actually stands a chance of getting printed on reagent bottles, in catalogs, in patent applications, or anywhere else chemists are using chemical information. Aside from its length, it's not too different from that other molecular identifier system , but without the perpetual use tax.

26. MD5 Hashing Function - Version 1.0 The following example shows a valid MD5 resinfo extension with two MD5 hashes of the referenced information resource. The first without a date, http://www.w3.org/TR/1998/REC-DSig-label/MD5-1_0

MD5 Hash Algorithm - Version 1.0 This document provides an overview of the Message Digest 5, and details how a MD5 digest is encoded in a Resource Reference Information Extension, providing the digest of a referenced web resource. Status of this Document This document is part of the DSig 1.0 Recommendation . It has been reviewed by W3C Members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. Last updated: 1998-05-27T18:31:36Z Overview This hash algorithm is identified by the URL http://www.w3.org/TR/1998/REC-DSig-label/MD5-1_0 The hash algorithm is defined in The MD5 Message Digest Algorithm , R.L. Rivest, RFC 1321 , April 1992 The MD5 algorithm (Message Digest 5) is a cryptographic message digest algorithm. MD5 was designed by Ron Rivest , who is also the `R' in `RSA' in 1991. MD5 is described in . C source code is included with the RFC. It is basically MD4 with "safety-belts" and while it is slightly slower than MD4, it is more secure. The algorithm consists of four distinct rounds, which have a slightly different design from that of MD4. Message-digest size, as well as padding requirements, remains the same. Den Boer and Bosselaers [B. den Boer and A. Bosselaers. Collisions for the compression function of MD5. In Advances in Cryptology - Eurocrypt '93 , pages 293-304, Springer-Verlag, 1994.] have found pseudo-collisions for MD5 (

27. Piecewise Hashing - Forensics Wiki Piecewise hashing is a hashing technique to divide an input into chunks and hash each chunk separately. It was invented by Nick Harbour in dcfldd to improve http://www.forensicswiki.org/index.php?title=Piecewise_hashing

28. Entity Crisis: Spatial Hashing A spatial index (in this example, a Spatial Hash / Hash Map) stores all object positions, and can quickly tell you what objects _might_ be colliding in a http://entitycrisis.blogspot.com/2007/11/spatial-hashing.html

skip to main skip to sidebar Entity Crisis Games, Web, Graphics, Audio and Information Systems. In Python. Thursday, November 15, 2007 Spatial Hashing Often, when building a game, you need to test if objects are colliding. The objects could be spaceships, rocks, mouse pointers, laser beams... whatever. The simple approach is to iterate over all your objects, and test if they collide with a specific point. If you do this using a linear algorithm, you'll quickly find that as you get more and more objects, your collision detection code will slow down at the same rate. from math import floor class HashMap(object): Hashmap is a a spatial index which can be used for a broad-phase collision detection strategy. def init(self, cell_size): self.cell_size = cell_size @classmethod def from_points(cls, cell_size, points): Build a HashMap from a list of points. hashmap = cls(cell_size) setdefault = hashmap.grid.setdefault key = hashmap.key for point in points: setdefault(key(point),[]).append(point)

29. Animation Such a function is known as a perfect hashing function it maps each key to a Unfortunately, finding a perfect hashing function is not always possible. http://www.cs.pitt.edu/~kirk/cs1501/animations/Hashing.html

Data Structures and Algorithms 8.3 Hash Tables Animation Hash Table Animation This animation was written by Woi Ang. Please email comments to: morris@ee.uwa.edu.au 8.3.1 Direct Address Tables If we have a collection of n elements whose keys are unique integers in (1, m ), where m n then we can store the items in a direct address table, T[m] where T i is either empty or contains one of the elements of our collection. Searching a direct address table is clearly an O(1) operation: for a key, k , we access T k if it contains an element, return it, if it doesn't then return a NULL. There are two constraints here: the keys must be unique, and the range of the key must be severely bounded. If the keys are not unique, then we can simply construct a set of m lists and store the heads of these lists in the direct address table. The time to find an element matching an input key will still be O(1) However, if each element of the collection has some other distinguishing feature (other than its key), and if the maximum number of duplicates is n dup max , then searching for a specific element is O(n dup max . If duplicates are the exception rather than the rule, then

30. Security Briefs: Hashing Passwords, The AllowPartiallyTrustedCallers Attribute A cryptographic hash algorithm like SHA1 or MD5 is a sophisticated one-way function that takes some input and produces a hash value as output, http://msdn2.microsoft.com/en-us/magazine/cc164107.aspx

var jsDomain='http://i2.msdn.microsoft.com';var jsBuildNumber='-bn1795.1'; Welcome Sign In Click here to Install Silverlight. United States - English Argentina (Espa±ol) ... Microsoft.com Product Families Office Windows Windows Server System Windows Mobile ... MSN Resources Microsoft Update Office Update Download Center Security ... Volume Licensing About Microsoft Company Information Investor Relations PressPass for journalists Popular Places MSDN (Developers) TechNet (IT Pros) Microsoft At Home Microsoft At Work ... Microsoft.com site map Popular Searches Templates ActiveSync Clip art Popular Downloads Windows Defender Beta 2 DirectX End-User Runtime More popular downloads Search MSDN ... Live Search MSDN Magazine Home Subscribe Reader Services Community ... RSS Printer Friendly Version Send Click to Rate and Give Feedback Give feedback on this content MSDN MSDN Home MSDN Library MSDN Learn ... Resource File: Creating Privacy-awa... Security Briefs: Hashing Passwords,... Share this Page Live Favorites DotNet Kicks Digg Slashdot ... reddit Related Articles ASP.NET MVC: Building Web Apps without Web Forms

31. RFC 2104 HMAC: Keyed-Hashing For Message Authentication HMAC Keyedhashing for Message Authentication. H. Krawczyk, M. Bellare, R. Canetti. February 1997. http://tools.ietf.org/html/rfc2104

RFCs/IDs Plain Text ] [From draft-ietf-ipsec-hmac-md5 INFORMATIONAL Errata Network Working Group H. Krawczyk Request for Comments: 2104 IBM Category: Informational M. Bellare UCSD R. Canetti IBM February 1997 HMAC: Keyed-Hashing for Message Authentication Status of This Memo This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract This document describes HMAC, a mechanism for message authentication using cryptographic hash functions. HMAC can be used with any iterative cryptographic hash function, e.g., MD5, SHA-1, in combination with a secret shared key. The cryptographic strength of HMAC depends on the properties of the underlying hash function. . Introduction Providing a way to check the integrity of information transmitted over or stored in an unreliable medium is a prime necessity in the world of open computing and communications. Mechanisms that provide such integrity check based on a secret key are usually called "message authentication codes" (MAC). Typically, message authentication codes are used between two parties that share a secret key in order to validate information transmitted between these parties. In this document we present such a MAC mechanism based on cryptographic hash functions. This mechanism, called HMAC, is based on work by the authors [

32. The Guide To Hashing In Korea, Hash House Harriers Korea Hasher s Information Resource, National and Regional Hash House Harriers Link Page. All the resources needed to hash around the world. http://gotothehash.net/korea.html

Hash Info World Hash Links Hash T-Shirt Museum Hash Webkit Hash Humor ... Travel Resource Korea Info Life in Korea Lonely Planet FREE E-mail AOL Beer Excite Lycos ... Yahoo This site online since 12/97 Click on the hashes above for details. Former Hashers of Korea - In Transit Read the feature article from the Korea Herald Updated 17 February 2007 Guide to Hashing in Korea name="Webmaster" at=""@ domain="gotothehash.net" document.write(""+name+""+at+""+domain+"")

33. Hashraleigh.com - Hashing Doesn't Suck. When and where to run with the Carolina Larrikins Hash House Harriers, and who to ask about them, a club running pickup trails in the Triangle area. http://www.hashraleigh.com/

Contribute Advanced Search Site Statistics Directory ... Calendar Hashing doesn't suck. advanced search Topics Home hashraleigh.com Triangle H3 Sir Walter's H3 Carolina Larrikin H3 ... Interhashes Features Photo Gallery Buy TrH3 gear Welcome! Submit a story! User Functions Username Password Don't have an account yet? Sign up as a New User Lost your password Events There are no upcoming events Older Stories Monday 31-Dec Happy Belated New Year Hash, Jan 2nd, 2008 Speak Easy Booze It Or Loose It Hash #69 Thursday 22-Nov Larrikin's All-denomination Holiday Hash Inebriation - 19-Dec-07 Monday 19-Nov Sunday 04-Nov 3rd Anal Wing Whore's B-day 7thHash Wednesday November Monday 15-Oct Anal Death March/Parade of Halloweenies Thursday 11-Oct TWAT H3, Trail #1, Friday, Oct. 12 Burning Good Time Hash - Trail #69, 10/3/07 Recap Monday 01-Oct Burning Good Time Hash - Wed., Oct. 3rd, 6:30 pm Wednesday 05-Sep Carolina Larrikins -Gator Trail Libra Hash #69, Wed., Sept 19. - 6:30pm Welcome to hashraleigh.com Thursday, April 03 2008 @ 05:05 PM EDT NERDS! The R*nning of the Nerds Hash - Friday, April 4th - Raleigh Thursday, March 20 2008 @ 07:54 PM EDT Contributed by: Views: 18 WHO: If you can say or use a compass. If a protractor is a measurement

34. Hashing Concepts And The Java Programming Language Java, a new object oriented programming language, includes primitive hash functions in the language for each of the base types. However it provides no clues http://www.serve.net/buz/hash.adt/java.000.html

Hashing Concepts and the Java Programming Language Robert Uzgalis Computer Science Department University of Auckland Auckland, New Zealand Java, a new object oriented programming language, includes primitive hash functions in the language for each of the base types. However it provides no clues on how to combine hash values to produce a new hash value. This paper surveys hash function research in computer science emphasising recent developments, and then it critiques the hash facilities provided by Java followed by a proposal for an enhanced Java hash facility. The Java code for a generally applicable Hash class is given in the appendix. keywords: hash functions, hashing, Java, computer languages buz@zis.com home This paper was automatically translated from troff into html by t2h.

35. Web Caching With Consistent Hashing In this paper, we offer a new web caching strategy based on consistent hashing. Consistent hashing provides an alternative to multicast and directory http://www8.org/w8-papers/2a-webserver/caching/paper2.html

36. Collision-Resistant Hashing Towards Making UOWHFs Practical Abstract Recent attacks on the cryptographic hash functions MD4 and MD5 make it clear that (strong) collisionresistance is a hard-to-achieve goal. http://www.cs.ucsd.edu/~mihir/papers/tcr-hash.html

Collision-Resistant Hashing: Towards Making UOWHFs Practical Authors: M. Bellare and P. Rogaway Abstract: Recent attacks on the cryptographic hash functions MD4 and MD5 make it clear that (strong) collision-resistance is a hard-to-achieve goal. We look towards a weaker notion, the universal one-way hash functions Ref: Extended abstract was in Advances in Cryptology- Crypto 97 Proceedings, Lecture Notes in Computer Science Vol. 1294, B. Kaliski ed, Springer-Verlag, 1997. Full paper available below. Full paper: Available as compressed postscript postscript , or pdf Help if this doesn't work). Related work Improvements by Victor Shoup. Hash Functions: From Merkle-Damgard to Shoup by Ilya Mironov

37. Md5 Hashing Class Utility This class computes MD5 hashes. // Manually translated by Jon Howell buf is where the hash accumulates. long bits; // This is the count of bits hashed http://www.jonh.net/~jonh/md5/MD5.java

import java.io.*; import java.net.*; import java.util.*; import java.math.*; // This class computes MD5 hashes. // Manually translated by Jon Howell

38. Hashing In Forth hashing provides a fast way to search a large, unsorted data set at the cost of extra memory. Robert Sedgewick, in his book Algorithms, concisely describes http://www.forth.org/fd/hash.html

Hashing in Forth Xan Gregg Durham, North Carolina "The time/space tradeoff is what hashing is all about." Hashing provides a fast way to search a large, unsorted data set at the cost of extra memory. Robert Sedgewick, in his book Algorithms, concisely describes hashing as "directly referencing records in a table by doing arithmetic transformations on keys into table addresses." That should make sense to you by the end of this article, but first, let's consider a simple example. Suppose you have to write code to manage a database of about 50,000 records referenced by 16-bit record numbers. Record insertions and deletions are common, so they can't be too slow, and record look-ups are frequent and must be fast. You are given 64K of RAM in addition to the memory and disk space occupied by the data, and you know that each record is referenced by a unique three-letter code, like airports are in the U.S. As a Forth programmer, you realize that a three-letter string is also a three-digit base-26 number, and you make a table with 26 x 26 x 26=17,576 entries, with each entry containing the record number. Insertion and deletion are straightforward you just have to update the table with each operation. Finding a record from its key involves only packing three letters into a 15-bit number and using it as an index into the table. Then you have the record number. If you can do that, you already understand the basic concepts of hashing. Hashing requires a hash function and a hash table. The hash function converts a key value, such as a text string or a large number, into a hash table address. Each entry in the hash table points to a record in the data set.

39. Consistent Hashing And Random Trees Robert Devine, Design and Implementation of DDH A Distributed Dynamic hashing Algorithm, Proceedings of the 4th International Conference on Foundations of http://portal.acm.org/citation.cfm?id=258660

40. Brian Jones: Open XML Formats : Improvements In Password Hashing There were a number of comments raised by national bodies about the password hashing (encryption) support defined in Open XML. There were some extra hurdles http://blogs.msdn.com/brian_jones/archive/2008/01/23/improvements-in-password-ha

Welcome to MSDN Blogs Sign in Join Help Brian Jones: Open XML Formats I'm Brian Jones, a program manager in Office. I've been working on the XML functionality and file formats in Office for about 6 years now. In this blog, I'll mainly focus on XML in Office and the Open XML File Formats coming in the 2007 Microsoft Office system. This Blog Email Syndication RSS 2.0 Atom 1.0 Search Go News View blog authority var sc_project=3367571; var sc_invisible=1; var sc_partition=37; var sc_security="9da07350"; Blogs I Read Jon Udell (MSFT) OpenXML to ODF converter team blog Dare Obasanjo (MSFT) Stephen McGibbon (MSFT) ... Alexander Falk (XML Aficianado) Office 2007 Blogs Chris Pratley - Word, OneNote, design, and development Jensen Harris - Office User Interface David Gainer - Excel Rob Mauceri - FrontPage ... Infopath Team Blog Tags 3rd Party Tools Code Samples Compatibility Pack Conferences ... WordprocessingML Recent Posts Open XML Overwhelmingly Approved as an ISO / IEC standard (IS 29500): the end of the file formats wa Open XML Resources for Developers German standards body responds to "incorrect and misleading" reports Norway vote is now “yes” for Open XML ... South Korea vote is now “yes” for Open XML Archives April 2008 (1) March 2008 (24) February 2008 (8) January 2008 (18) ... May 2005 (1) Improvements in Password Hashing There were a number of comments raised by national bodies about the password hashing (encryption) support defined in Open XML. There were some extra hurdles that we had initially put to ensure that we could upgrade an existing binary documents properly. On further discussion in TC45 though, we decided that this extra step should only be necessary with a legacy document where the password hasn't already been entered. For any new document, or any time the password has been verified, we'll now use a much cleaner approach.

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