initial Crypto

Will use Ed25519 because it's from DJB and well regarded and in common
use now.

1 files changed, 24 insertions, 0 deletions

diff --git a/Crypto.hs b/Crypto.hs
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--- /dev/null
+++ b/Crypto.hs
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+module Crypto where
+
+import Val
+import Hash
+import Types
+
+import qualified Crypto.PubKey.Ed25519 as Ed25519
+import Data.ByteArray (convert)
+import Crypto.Error
+
+dummySignature :: Signature
+dummySignature = Unsigned
+
+-- | Sign any Hashable value.
+sign :: Hashable v => Ed25519.SecretKey -> Ed25519.PublicKey -> v -> Signature
+sign sk pk v = Ed25519 $ Val $ convert $
+	Ed25519.sign sk pk $ val $ hashValue $ hash v
+
+-- | Verifiy a signature of any Hashable value.
+verify :: Hashable v => Ed25519.PublicKey -> v -> Signature -> Bool
+verify pk v (Ed25519 (Val s)) = case Ed25519.signature s of
+	CryptoPassed sig -> Ed25519.verify pk (val $ hashValue $ hash v) sig
+	CryptoFailed _ -> False
+verify _ _ Unsigned = False