Verify.hs

{-|
Module      : Botan.Low.Verify
Description : Signature Verification
Copyright   : (c) 2023-2024, Apotheca Labs
              (c) 2024-2025, Haskell Foundation
License     : BSD-3-Clause
Maintainer  : joris@well-typed.com, leo@apotheca.io
Stability   : experimental
Portability : POSIX
-}

module Botan.Low.PubKey.Verify (

  -- * Public key signature verification
    Verify(..)
  , withVerify
  , verifyCreate
  , verifyDestroy
  , verifyUpdate
  , verifyFinish

  ) where

import           Botan.Bindings.ConstPtr (ConstPtr (..))
import           Botan.Bindings.PubKey.Verify
import           Botan.Low.Error.Internal
import           Botan.Low.Internal.ByteString
import           Botan.Low.PubKey
import           Botan.Low.PubKey.Sign (SigningFlags, signingFlags)
import           Botan.Low.Remake
import           Data.ByteString (ByteString)
import           Foreign.C.Types
import           Foreign.ForeignPtr
import           Foreign.Ptr

-- /*
-- * Signature Verification
-- */

newtype Verify = MkVerify { foreignPtr :: ForeignPtr BotanPKOpVerifyStruct }

withVerify     :: Verify -> (BotanPKOpVerify -> IO a) -> IO a
verifyDestroy  :: Verify -> IO ()
createVerify   :: (Ptr BotanPKOpVerify -> IO CInt) -> IO Verify
(withVerify, verifyDestroy, createVerify)
    = mkBindings
        MkBotanPKOpVerify (.ptr)
        MkVerify (.foreignPtr)
        botan_pk_op_verify_destroy

verifyCreate
    :: PubKey       -- ^ __key__
    -> EMSAName     -- ^ __hash_and_padding__
    -> SigningFlags -- ^ __flags__
    -> IO Verify    -- ^ __op__
verifyCreate pk algo flags =  withPubKey pk $ \ pkPtr -> do
    asCString algo $ \ algoPtr -> do
        createVerify $ \ out -> botan_pk_op_verify_create
            out
            pkPtr
            (ConstPtr algoPtr)
            (signingFlags flags)

verifyUpdate
    :: Verify       -- ^ __op__
    -> ByteString   -- ^ __in[]__
    -> IO ()
verifyUpdate = mkWithObjectSetterCBytesLen withVerify botan_pk_op_verify_update

-- TODO: Signature type
verifyFinish ::
     Verify       -- ^ __op__
  -> ByteString   -- ^ __sig[]__
  -> IO Bool
verifyFinish verify sig =
    withVerify verify $ \ verifyPtr ->
    asBytesLen sig $ \ sigPtr sigLen ->
    throwBotanCatchingInvalidVerifier $ botan_pk_op_verify_finish
      verifyPtr
      (ConstPtr sigPtr)
      sigLen