sign.hs

{-# LANGUAGE OverloadedStrings #-}
import Data.Maybe
import OpenSSL.EVP.Sign
import OpenSSL.EVP.Verify
import OpenSSL.EVP.Digest
import OpenSSL.PEM
import OpenSSL
import Control.Applicative

main :: IO ()
main =
    -- Set up ctx, *important*
    withOpenSSL $ do
        -- Read the private key generated via openssl genrsa -out key.pem 2048
        --
        -- PwNone means that there shouldn't be a password
        pri <- readFile "key.pem" >>= flip readPrivateKey PwNone

        sha <- fromMaybe (error "no sha256") <$> getDigestByName "sha256"

        let msg = "hello"
        signature <- signBS sha pri msg

        -- Client side verification now.

        -- If you have access to the private key, you can simply use that.
        pub <- readFile "key.pub" >>= readPublicKey

        -- Result is VerifySuccess or VerifyFailure
        verifyBS sha signature pub msg >>= print