[tahoe-dev] Recombinant Hashes

Chris Dew cmsdew at googlemail.com
Thu Feb 11 18:22:35 UTC 2010

Yes, my algorithm seems to have the properties of a fountain code.

Thanks for the link - I hadn't heard of fountain codes before.  It
seems that I haven't discovered something new :-(

All the best,


On 11 February 2010 18:10, Brian Warner <warner at lothar.com> wrote:
> Chris Dew wrote:
>> Hi, I just read about this project on Reddit, and wondered whether you
>> use an algorithm similar to that which I've developed.
>> It lets you make an unlimited amount of hashes from some data.  So
>> long as the total length of the hashes you possess are greater than
>> the length of the original data, you can recreate the original data -
>> regardless of which combination of hashes you possess.
> I think we're using a similar approach. I haven't heard the term "hash"
> for the pieces, though.. I've only heard "share" or "block" or sometimes
> "packet" for the pieces. (using "hash" seems likely to get confused with
> a secure cryptographic hash, from which you'd never be able to get back
> to the original data, of course).
> We use Reed-Solomon erasure coding, which produces a limited number of
> shares. There is a different sort of erasure codes called Fountain Codes
> which can produce an effectively-unlimited number of shares
> (http://en.wikipedia.org/wiki/Fountain_code) .. is your algorithm like
> one of those?
> cheers,
>  -Brian
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