secret-sharing-1.0.0.3: Information-theoretic secure secret sharing
Implementation of an (m
,n
)-threshold secret sharing scheme.
A given ByteString b
(the secret) is split into n
shares,
and any m
shares are sufficient to reconstruct b
.
The scheme preserves information-theoretic perfect secrecy in the sense that the knowledge of up
to m-1
shares does not reveal any information about the secret b
.
Example in GHCi: Suppose that you want to split the string "my secret data" into n=5 shares such that at least m=3 shares are necessary to reconstruct the secret.
> :m + Data.ByteString.Lazy.Char8 Crypto.SecretSharing > let secret = pack "my secret message!" > shares <- encode 3 5 secret > mapM_ (Prelude.putStrLn . show) shares -- each share should be deposited at a different site. (1,"\134\168\154\SUBV\248\CAN:\250y<\GS\EOT*\t\222_\140") (2,"\225\206\241\136\SUBse\199r\169\162\131D4\179P\210x") (3,"~\238%\192\174\206\\\f\214\173\162\148\&3\139_\183\193\235") (4,"Z\b0\188\DC2\f\247\f,\136\&6S\209\&5\n\FS,\223") (5,"x\EM\CAN\DELI*<\193q7d\192!/\183v\DC3T") > let shares' = Prelude.drop 2 shares > decode shares' "my secret message!"
The mathematics behind the secret sharing scheme is described in: "How to share a secret." by Adi Shamir. In Communications of the ACM 22 (11): 612–613, 1979.
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