Comments on: 1bc29b36f623ba82aaf6724fd3b16718

By: p vs np

p vs np — Sun, 02 Aug 2009 13:23:24 +0000

It’s the Pigeon Hole Principle doing kireek in Hash tables,_quote_ because the number of possible keys exceeds the number of indices in the array. No hashing algorithm, no matter how clever, can avoid these collisions. _quote_

By: Deepthi JS

Deepthi JS — Sun, 02 Aug 2009 12:36:27 +0000

1–> Pigeon Hole Principle and 2–> algorithm for hashing.According to wiki,collisions are inevitable in a hash table because the number of possible keys exceeds the number of indices in the array.

By: username

username — Sun, 02 Aug 2009 09:49:42 +0000

1. Pigeonhole principle
2. MD5: hash algorithm

collisions are inevitable in a hash table because the number of possible keys exceeds the number of indices in the array. No hashing algorithm, no matter how clever, can avoid these collisions.

http://en.wikipedia.org/wiki/Pigeonhole_principle

By: Joshan

Joshan — Sun, 02 Aug 2009 05:01:52 +0000

pigeon hole principle…….This principle states that, given two natural numbers n and m with n > m, if n items are put into m pigeonholes, then at least one pigeonhole must contain more than one item.

By: kiran

kiran — Sat, 01 Aug 2009 18:33:32 +0000

Pigeonhole principle, sha, problem – collisions

By: piezocake

piezocake — Sat, 01 Aug 2009 16:36:22 +0000

The pigeon-hole principle makes the Boolean satisfiability problem NP-hard ?

By: blackrat

blackrat — Sat, 01 Aug 2009 07:19:06 +0000

The pigeonhole principle (fig. 1) forms the basis of collision resolution techniques. An unfortunate juxtaposition also being, you cannot escape collisions when it comes to hashing.
Any good hashing algorithm avoids collision. However that becomes a distinct impossibility as soon as the data-size(pigeons) exceeds the checksum size(pigeonholes), regardless of algorithmic jugglery.

The Vulnerability of SHA-1 (fig. 2) was brought to light by Xiaoyun Wang @ Shandong U. Devising a method for replicating collisions nearly 2^12 times faster(in terms of algo. complexity) than what is agreed to be computationally secure.

By: Rogi

Rogi — Sat, 01 Aug 2009 06:23:25 +0000

Would it suffice to simply say, *collisions*?

By: madhur

madhur — Fri, 31 Jul 2009 23:18:08 +0000

1. Pigeon Hole Principle
2. MD5

By: Ananth

Ananth — Fri, 31 Jul 2009 19:59:40 +0000

1) Pigeon hole principle
2) Some hashing algo ( SHA1 I guess)

Accd Pigeon hole principle: No hashing algorithm, no matter how clever, can avoid collisions.