Integrate Bech32 decoding into Sapling key validation

src/ZcashHaskell/Sapling.hs

@@ -14,10 +14,12 @@ import qualified Data.ByteString as BS
 import Foreign.Rust.Marshall.Variable (withPureBorshVarBuffer)
 import ZcashHaskell.Types
   ( DecodedNote(..)
+  , RawData(..)
   , RawTxResponse(..)
   , ShieldedOutput(..)
   , decodeHexText
   )
+import ZcashHaskell.Utils (decodeBech32)
 
 -- | Check if given bytesting is a valid encoded shielded address
 isValidShieldedAddress :: BS.ByteString -> Bool
@@ -28,7 +30,12 @@ getShieldedOutputs t = withPureBorshVarBuffer $ rustWrapperTxParse t
 
 -- | Check if given bytestring is a valid Sapling viewing key
 isValidSaplingViewingKey :: BS.ByteString -> Bool
-isValidSaplingViewingKey = rustWrapperSaplingVkDecode
+isValidSaplingViewingKey k =
+  case hrp decodedKey of
+    "zxviews" -> rustWrapperSaplingVkDecode $ bytes decodedKey
+    _ -> False
+  where
+    decodedKey = decodeBech32 k
 
 -- | Check if the given bytestring for the Sapling viewing key matches the second bytestring for the address
 matchSaplingAddress :: BS.ByteString -> BS.ByteString -> Bool

test/Spec.hs

@@ -279,7 +279,7 @@ main = do
       let rawSa' = decodeBech32 sa'
       it "is mainnet" $ do hrp rawKey `shouldBe` "zxviews"
       it "is valid Sapling extended full viewing key" $ do
-        isValidSaplingViewingKey (bytes rawKey) `shouldBe` True
+        isValidSaplingViewingKey vk `shouldBe` True
       it "matches the right Sapling address" $ do
         matchSaplingAddress (bytes rawKey) (bytes rawSa) `shouldBe` True
       it "doesn't match the wrong Sapling address" $ do