Update Sapling spending key with coin type

Reviewed-on: #31

librustzcash-wrapper/src/lib.rs

@@ -59,11 +59,12 @@ use zcash_address::{
 };
 
 use zcash_client_backend::keys::sapling::{
+    spending_key,
     ExtendedFullViewingKey,
     ExtendedSpendingKey
 };
 
-use zcash_primitives::zip32::{ AccountId, DiversifierIndex };
+use zcash_primitives::zip32::DiversifierIndex;
 
 use orchard::{
     Action,
@@ -627,23 +628,16 @@ pub extern "C" fn rust_wrapper_recover_seed(
 
 #[no_mangle]
 pub extern "C" fn rust_wrapper_sapling_spendingkey(
-    iseed: *const u8,
-    iseed_len: usize,
-    ix: u32,
+    seed: *const u8,
+    seed_len: usize,
+    coin_type: u32,
+    acc_id: u32,
     out: *mut u8,
     out_len: &mut usize
     ){
-    let seed: Vec<u8> = marshall_from_haskell_var(iseed, iseed_len, RW);
-    let su8 = &seed;
-    let seedu8 : &[u8] = &su8;
-    let extsk: ExtendedSpendingKey = ExtendedSpendingKey::master(&seedu8); 
-    if ix == 0 {
-        let extsk_bytes = extsk.to_bytes().to_vec(); 
-        marshall_to_haskell_var(&extsk_bytes, out, out_len, RW);
-    } else {
-        let child_sk = extsk.derive_child(ChildIndex::from_index(ix + (1 << 31)));
-        marshall_to_haskell_var(&child_sk.to_bytes().to_vec(), out, out_len, RW);
-    }
+    let s: Vec<u8> = marshall_from_haskell_var(seed, seed_len, RW);
+    let sk = spending_key(&s, coin_type, zcash_primitives::zip32::AccountId::try_from(acc_id).unwrap());
+    marshall_to_haskell_var(&sk.to_bytes().to_vec(), out, out_len, RW);
 }
 
 #[no_mangle]

src/C/Zcash.chs

@@ -137,6 +137,7 @@ import ZcashHaskell.Types
 {# fun unsafe rust_wrapper_sapling_spendingkey as rustWrapperSaplingSpendingkey
      { toBorshVar* `BS.ByteString'&
      , `Word32'
+     , `Word32'
      , getVarBuffer `Buffer (BS.ByteString)'&
      }
   -> `()'

src/ZcashHaskell/Sapling.hs

@@ -46,6 +46,7 @@ import ZcashHaskell.Types
   , Seed(..)
   , ShieldedOutput(..)
   , decodeHexText
+  , getValue
   )
 import ZcashHaskell.Utils (decodeBech32)
 
@@ -95,15 +96,18 @@ instance FromJSON RawTxResponse where
           pure $ RawTxResponse i h (getShieldedOutputs h) a ht c b
 
 -- | Attempts to obtain a sapling SpendingKey using a HDSeed
-genSaplingSpendingKey :: Seed -> Int -> Maybe SaplingSpendingKey
-genSaplingSpendingKey seed i = do
+genSaplingSpendingKey :: Seed -> CoinType -> Int -> Maybe SaplingSpendingKey
+genSaplingSpendingKey seed c i = do
   if BS.length res == 169
     then Just res
     else Nothing
   where
     res =
       withPureBorshVarBuffer
-        (rustWrapperSaplingSpendingkey seed (fromIntegral i))
+        (rustWrapperSaplingSpendingkey
+           seed
+           (fromIntegral $ getValue c)
+           (fromIntegral i))
 
 -- | Attempts to generate a sapling Payment Address using an ExtendedSpendingKey and a Diversifier Index 
 genSaplingPaymentAddress :: Int -> SaplingSpendingKey -> Maybe SaplingReceiver

test/Spec.hs

@@ -604,7 +604,7 @@ main = do
             Nothing -> return $ expectationFailure "Failed to generate seed"
             Just s' -> do
               let oK = genOrchardSpendingKey s' MainNetCoin 0
-              let sK = genSaplingSpendingKey s' 0
+              let sK = genSaplingSpendingKey s' MainNetCoin 0
               let tK = genTransparentPrvKey s'
               let oR = genOrchardReceiver 0 =<< oK
               let sR = genSaplingPaymentAddress 0 =<< sK
@@ -623,7 +623,7 @@ main = do
             Nothing -> return $ expectationFailure "Failed to generate seed"
             Just s' -> do
               let oK = genOrchardSpendingKey s' MainNetCoin 0
-              let sK = genSaplingSpendingKey s' 0
+              let sK = genSaplingSpendingKey s' MainNetCoin 0
               let tK = genTransparentPrvKey s'
               let oR = genOrchardReceiver 0 =<< oK
               let sR = genSaplingPaymentAddress 0 =<< sK
@@ -654,19 +654,20 @@ prop_OrchardReceiver ::
 prop_OrchardReceiver s c (NonNegative i) (NonNegative j) =
   genOrchardReceiver j (fromMaybe "" $ genOrchardSpendingKey s c i) =/= Nothing
 
-prop_SaplingSpendingKey :: Seed -> NonNegative Int -> Property
-prop_SaplingSpendingKey s (NonNegative i) =
-  genSaplingSpendingKey s i =/= Nothing
+prop_SaplingSpendingKey :: Seed -> CoinType -> NonNegative Int -> Property
+prop_SaplingSpendingKey s c (NonNegative i) =
+  genSaplingSpendingKey s c i =/= Nothing
 
-prop_SaplingReceiver :: Seed -> NonNegative Int -> NonNegative Int -> Property
-prop_SaplingReceiver s (NonNegative i) (NonNegative j) =
-  genSaplingPaymentAddress i (fromMaybe "" $ genSaplingSpendingKey s j) =/=
+prop_SaplingReceiver ::
+     Seed -> CoinType -> NonNegative Int -> NonNegative Int -> Property
+prop_SaplingReceiver s c (NonNegative i) (NonNegative j) =
+  genSaplingPaymentAddress i (fromMaybe "" $ genSaplingSpendingKey s c j) =/=
   Nothing
 
-prop_SaplingRecRepeated :: Seed -> NonNegative Int -> Property
-prop_SaplingRecRepeated s (NonNegative i) =
-  genSaplingPaymentAddress i (fromMaybe "" $ genSaplingSpendingKey s 1) =/=
-  genSaplingPaymentAddress (i + 1) (fromMaybe "" $ genSaplingSpendingKey s 1)
+prop_SaplingRecRepeated :: Seed -> CoinType -> NonNegative Int -> Property
+prop_SaplingRecRepeated s c (NonNegative i) =
+  genSaplingPaymentAddress i (fromMaybe "" $ genSaplingSpendingKey s c 1) =/=
+  genSaplingPaymentAddress (i + 1) (fromMaybe "" $ genSaplingSpendingKey s c 1)
 
 prop_OrchardRecRepeated ::
      Seed -> CoinType -> NonNegative Int -> NonNegative Int -> Property