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Shamir's Secret Sharing

en.wikipedia.org

1–10 of 19 posts

Re: Shamir's Secret Sharing

#3
Some software using this algorithm:

http://www.digital-scurf.org/software/libgfshare

https://github.com/ryancdotorg/threshcrypt (uses libgfshare, written by me - handles large files by splitting a key into shares and encrypting them with password-derived keys)

https://github.com/amper5and/secrets.js/

http://passguardian.com/ (uses secrets.js)

http://point-at-infinity.org/ssss/

Re: Shamir's Secret Sharing

#4
I've been wanting to use this in combination with Rabin's Information Dispersal algorithm to create an autonomous distributed file storage system. You would have redundancy, but redundancy in a way that you only require k of n "pieces" to recover your original file (or data object). This is pretty cool, because you don't need to have 10 copies of a 1 GB file (10 GB total) spread about the web in order to achieve a high probability of being able to recover your data.

Re: Shamir's Secret Sharing

#5

I've been wanting to use this in combination with Rabin's Information Dispersal algorithm to create an autonomous distributed file storage system. You would have redundancy, but redundancy in a way that you only require k of n "pieces" to recover your original file (or data object). This is pretty cool, because you don't need to have 10 copies of a 1 GB file (10 GB total) spread about the web in order to achieve a hi…

When you encode information with Shamir Secret Sharing, each share is actually bigger than the original secret. The computation requirements also don't scale very well. What you want is called Erasure Coding. (https://en.wikipedia.org/wiki/Erasure_code)

Re: Shamir's Secret Sharing

#7
The wikipedia link gets mathematical very quickly.

With Shamir's secret sharing you can take a file and split it for example into 3 parts. Only 2 parts would need to be combined to re-create the original. This would be 2 of 3 in Bitcoin parlance.

Re: Shamir's Secret Sharing

#9
post #6

Vault uses this technique https://www.vaultproject.io/

I came across the algorithm while going through the project. One interesting feature of the technique is that it is possible to set the threshold less that total number of parts to recreate the secret and it is used by the software.
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