note 39622 added to function.uniqid
| From: | tbreslowREMOVE-NOSPAM at yahoo dot com | Date: | Wed, 04 Feb 2004 23:39:02 +0000 |
| Subject: | note 39622 added to function.uniqid | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-64656@lists.php.net to get a copy of this message | ||
the idea that two strings out of 50,000 could evaluate to the same md5 hash is quite impossible.
there are 2^128 MD5 values. an interesting proof showed that given 10^19 inputs there would still be
less than a 50% probability of a duplicate hash. assuming you had a computer that could process md5
hashes in 1 ms it would take 10^19ms (370,000 years) of hashing to have less than 50% chance of
finding a duplicate. if you really did find two strings that have the same md5 hash you will be
quite famous.
see http://www.cs.bham.ac.uk/~mdr/teaching/modules/security/hash.html
for the proof.</p>
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