This is a trivial Haskell binding to floodyberry's Ed25519 C implementation in much the same style as ACW's curve25519 bindings.
Usage
Just import, generate keys, sign and verify:
{-# LANGUAGE OverloadedStrings #-}
import Crypto.Ed25519
import Crypto.Random
import Data.ByteString.Char8 ()
main :: IO ()
main =
do g1 <- newGenIO :: IO SystemRandom
let (q1,p1,g2) = generateKeyPair g1
(q2,p2,_) = generateKeyPair g2
msg1 = "Some message I want to sign."
msg2 = "Another message someone else signed"
sig1 = sign msg1 q1 p1
sig2 = sign msg2 q2 p2
putStrLn "Valid signature and public key pairs: "
print $ valid msg1 p1 sig1
print $ valid msg2 p2 sig2
putStrLn "Invalid signature and public key pairs: "
print $ valid msg1 p2 sig2
print $ valid msg2 p1 sig2
Batch Signature Verification
One of the features of Ed25519 is the ability to perform batch signature verification. This is harder to support than might be expected due to its need for cryptographically strong random numbers during batch verification. I have an issue filed with the upstream package to allow the randomness as an additional parameter. Till then you'll have to do without or cook-up your own one-off binding.