md5 and large files
Brad Tilley
bradtilley at gmail.com
Mon Oct 18 16:34:54 EDT 2004
Josiah Carlson wrote:
>>Of course I can't... *grin* -- But actually, (correct me if I'm wrong) an
>>MD5 sum is 128 bits long, that are 2^128 different possibilities. Now a 2
>>GB file has 8*2*1024^3 bits, that are 2^17179869184 different
>>possibilities for a 2 GB file. Am I wright thinking that the number of
>>files with an identical md5 sum is now 2^17179869184 / 2^128 =
>>2^17179869056?
>
>
> (I know this is a major simplification, but bear with me)
>
> Your probability and numbers are correct. The problem is that 2^128 is
> so damn huge
All you need is 2^128+1 to find a duplicate, no? The problem, as I
understand it, is getting to the end (2^128+1) as sufficient computing
power isn't available... yet.
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