Crypto Multihash

Multihash library implemented on top of cryptonite cryptographic library.
Multihash is a protocol for encoding the hash algorithm and digest length at the start of the digest, see the official multihash github page.
This library is still experimental and the api is not guaranteed stable.
I will increment the version number appropriately in case of breaking changes.
For the moment the library implements all the expected hashing algorithms with the exception of shake-128 and shake-256. A Multihash can be encoded in hex (Base16
), bitcoin base58 (Base58
) and base64 (Base64
).
The Base32
encoding is not yet supported due to discrepancy between the encoding from Data.ByteArray.Encoding
and the one appearing in the official multihash page.
Usage
-- in ghci `:set -XOverloadedStrings`
{-# LANGUAGE OverloadedStrings #-}
import Crypto.Multihash
import Data.ByteString (ByteString)
main = do
let v = "test"::ByteString
let m = multihash SHA256 v
putStrLn $ "Base16: " ++ (encode' Base16 m)
-- You might need to specify the encoded string type
putStrLn $ "Base58: " ++ (encode' Base58 m :: String)
-- `encode` is the safe interface returning an `Either` type
putStrLn $ "Base64: " ++ show (encode Base64 m :: Either String String)
let h = encode' Base58 m :: ByteString
checkMultihash h v
-- Right True
-- There is also an unsafe version, as for encode
checkMultihash' "whatever" v
-- *** Exception: Unable to infer an encoding
checkMultihash' "Eiwhatever" v
-- *** Exception: base64: input: invalid length
checkMultihash' "EiCfhtCBiEx9ZZov6qDFWtAVo79PGysLgizRXWwVsPA1CA==" v
-- False
checkMultihash' h v
-- True
Test
Some preliminary tests can be performed with stack test
.
A simple example encoder is in app/Main.hs
.
You can run it on files
echo -n test | stack exec mh -- somefile someotherfile
or read data from the standard input
echo -n test | stack exec mh -- -`
Contribution
- Fork repository
- Do some changes
- Create pull request
- Wait for CI build and review
You can use stack to build the project: stack build
To run tests: stack test
TODO
Improve documentation
Implement hash checker that takes some data and an encoded multihash and check that the multihash corresponds to the data (inferring automatically the appropriate hash function)
Evaluate if throwing an error in the encode function is the wanted behaviour and anyway implement a safe version returning an Either type
- Add testing for
the newly introduced checker and for raised exceptions
- Add multihash checker into the cli example
- Implement
shake-128
and shake-256
multihashes
- Implement
Base32
encoding waiting for https://github.com/jbenet/multihash/issues/31 to be resolved)