!!! Overview
A [{$pagename}] ([One-Way Hash Function] [OWHF]) is a [Hash Function] with some additional [MUST] have all [Hash Function Security Properties].

If a [{$pagename}] can __NOT__ meet these requirements, the resulting [hash] is considered [Cryptographically Weak].

!! Most Common [{$pagename}]
ThŽe most commonly used [{$pagename}] function today (2015-03-15) is [SHA-1], which has output of 160 bits. (see [SHAttered] and [SHA-1 Deprecation])

!! Strength of [{$pagename}]
Unlike with [Ciphers], the strength of a [{$pagename}] doesn’t equal the [Hash] length. Because of the [Birthday Paradox] (a well-known problem in probability theory), the strength of a [{$pagename}] is at most one half of the [Hash] length.

The harder it is to compute raises the [Level Of Assurance].

Note that unlike hardness in most of complexity theory (e.g., NP-hardness), "hard" in the context of one-way functions refers to the [Computational Hardness Assumption] rather than worst-case hardness. 

The existence of "pure" one-way functions is an open conjecture. for more information see [Wikipedia:One-way_function]


!! [{$pagename}] and [Hash Function] properties
* [Hash Function Security|Hash Function Security Properties]
* [Cryptographic Hash Function Comparison]

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Cryptographic Hash Functions|Wikipedia:Cryptographic_hash_function|target='_blank'] - based on information obtained 2013-04-10
* [#1] - [One-way_function|Wikipedia:One-way_function|target='_blank'] - based on information obtained 2013-04-10