CHANGELOG.md

@@ -5,8 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.5.4.1]
+
+### Added
+
+- Functions to handle Sapling commitment trees, incremental witnesses and note positions
+
 ## [0.5.4.0]
 
+### Added
 - Function to decode Orchard actions with a spending key
 - Functions for Bech32 encoding
 - Function to encode a Sapling address

librustzcash-wrapper/src/lib.rs

@@ -6,7 +6,8 @@ use std::{
     marker::PhantomData,
     io::{
         Write,
-        Cursor
+        Cursor,
+        Error
     },
 };
 
@@ -23,11 +24,20 @@ use haskell_ffi::{
     FromHaskell, HaskellSize, ToHaskell
 };
 
-use incrementalmerkletree::frontier::CommitmentTree;
+use incrementalmerkletree::{
+    frontier::CommitmentTree,
+    witness::IncrementalWitness
+};
 
 use zip32;
 
 use zcash_primitives::{
+    merkle_tree::{
+        read_commitment_tree,
+        write_commitment_tree,
+        read_incremental_witness,
+        write_incremental_witness
+    },
     zip32::{
         Scope as SaplingScope,
         ChildIndex,
@@ -57,6 +67,7 @@ use zcash_primitives::{
         MerklePath,
         NOTE_COMMITMENT_TREE_DEPTH as SAPLING_DEPTH,
         PaymentAddress,
+        note::ExtractedNoteCommitment as SaplingNoteCommitment,
         keys::{
             PreparedIncomingViewingKey as SaplingPreparedIncomingViewingKey,
             ExpandedSpendingKey,
@@ -188,6 +199,14 @@ pub struct Hhex {
     bytes: Vec<u8>
 }
 
+impl<RW> ToHaskell<RW> for Hhex {
+    fn to_haskell<W: Write>(&self, writer: &mut W, _tag: PhantomData<RW>) -> Result<()> {
+        self.serialize(writer)?;
+        Ok(())
+    }
+}
+
+
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct Haction {
     nf: Hhex,
@@ -221,7 +240,8 @@ impl Haction {
 pub struct Hnote {
     note: u64,
     recipient: Vec<u8>,
-    memo: Vec<u8>
+    memo: Vec<u8>,
+    nullifier: Vec<u8>
 }
 
 impl<RW> ToHaskell<RW> for Hnote {
@@ -713,6 +733,7 @@ pub extern "C" fn rust_wrapper_sapling_esk_decrypt(
     note_len: usize,
     external: bool,
     net: bool,
+    pos: u64,
     out: *mut u8,
     out_len: &mut usize
  ){
@@ -740,24 +761,24 @@ pub extern "C" fn rust_wrapper_sapling_esk_decrypt(
                     else {zcash_note_encryption::try_note_decryption(&test_domain, &pivk, &action2)};
                     match result {
                         Some((n, r, m)) => {
-                            //let nullifier = n.nf(&nk, MerklePath<Node::from_cmu(&n.cmu()), SAPLING_DEPTH>.position());
+                            let nullifier = n.nf(&nk, pos);
-                            let hn = Hnote {note: n.value().inner(), recipient: r.to_bytes().to_vec(), memo: m.as_slice().to_vec() };
+                            let hn = Hnote {note: n.value().inner(), recipient: r.to_bytes().to_vec(), memo: m.as_slice().to_vec(), nullifier: nullifier.to_vec() };
                             marshall_to_haskell_var(&hn, out, out_len, RW);
                         },
                         None => {
-                            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+                            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
                             marshall_to_haskell_var(&hn0, out, out_len, RW);
                         }
                     }
                 },
                 Err(_e1) => {
-                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0] };
+                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0] };
                     marshall_to_haskell_var(&hn0, out, out_len, RW);
                 }
             }
         },
         Err(_e) => {
-            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0] };
+            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0] };
             marshall_to_haskell_var(&hn0, out, out_len, RW);
         }
     }
@@ -787,23 +808,23 @@ pub extern "C" fn rust_wrapper_sapling_note_decrypt_v2(
                     let result = zcash_note_encryption::try_note_decryption(&domain, &pivk, &action3);
                     match result {
                         Some((n, r, m)) => {
-                            let hn = Hnote {note: n.value().inner(), recipient: r.to_bytes().to_vec(), memo: m.as_slice().to_vec()};
+                            let hn = Hnote {note: n.value().inner(), recipient: r.to_bytes().to_vec(), memo: m.as_slice().to_vec(), nullifier: vec![0]};
                             marshall_to_haskell_var(&hn, out, out_len, RW);
                         }
                         None => {
-                            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+                            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
                             marshall_to_haskell_var(&hn0, out, out_len, RW);
                         }
                     }
                 },
                 Err(_e1) => {
-                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0] };
+                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0] , nullifier: vec![0]};
                     marshall_to_haskell_var(&hn0, out, out_len, RW);
                 }
             }
         }
         Err(_e) => {
-            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
             marshall_to_haskell_var(&hn0, out, out_len, RW);
         }
     }
@@ -837,17 +858,17 @@ pub extern "C" fn rust_wrapper_orchard_note_decrypt(
             let result = zcash_note_encryption::try_note_decryption(&domain, &pivk, &action);
             match result {
                 Some((n, r, m)) => {
-                    let hn = Hnote {note: n.value().inner(), recipient: r.to_raw_address_bytes().to_vec(), memo: m.to_vec()};
+                    let hn = Hnote {note: n.value().inner(), recipient: r.to_raw_address_bytes().to_vec(), memo: m.to_vec(), nullifier: vec![0]};
                     marshall_to_haskell_var(&hn, out, out_len, RW);
                 }
                 None => {
-                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+                    let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
                     marshall_to_haskell_var(&hn0, out, out_len, RW);
                 }
             }
         },
         None => {
-            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
             marshall_to_haskell_var(&hn0, out, out_len, RW);
         }
     }
@@ -885,11 +906,11 @@ pub extern "C" fn rust_wrapper_orchard_note_decrypt_sk(
     let result = zcash_note_encryption::try_note_decryption(&domain, &pivk, &action);
     match result {
         Some((n, r, m)) => {
-            let hn = Hnote {note: n.value().inner(), recipient: r.to_raw_address_bytes().to_vec(), memo: m.to_vec()};
+            let hn = Hnote {note: n.value().inner(), recipient: r.to_raw_address_bytes().to_vec(), memo: m.to_vec(), nullifier: vec![0]};
             marshall_to_haskell_var(&hn, out, out_len, RW);
         }
         None => {
-            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0]};
+            let hn0 = Hnote { note: 0, recipient: vec![0], memo: vec![0], nullifier: vec![0]};
             marshall_to_haskell_var(&hn0, out, out_len, RW);
         }
     }
@@ -1147,3 +1168,77 @@ pub extern "C" fn rust_wrapper_bech32_encode(
     marshall_to_haskell_var(&string, out, out_len, RW);
 }
 
+#[no_mangle]
+pub extern "C" fn rust_wrapper_read_sapling_commitment_tree(
+    tree: *const u8,
+    tree_len: usize,
+    node: *const u8,
+    node_len: usize,
+    out: *mut u8,
+    out_len: &mut usize
+    ){
+    let tree_in: Vec<u8> = marshall_from_haskell_var(tree, tree_len, RW);
+    let tree_reader = Cursor::new(tree_in);
+    let mut ct: CommitmentTree<Node, SAPLING_DEPTH> = read_commitment_tree(tree_reader).unwrap();
+
+    let node_in: Vec<u8> = marshall_from_haskell_var(node, node_len, RW);
+    let n = Node::from_cmu(&SaplingNoteCommitment::from_bytes(&to_array(node_in)).unwrap());
+    ct.append(n);
+    let mut out_bytes: Vec<u8> = Vec::new();
+    let result = write_commitment_tree(&ct, &mut out_bytes );
+    match result {
+        Ok(()) => {
+            let h = Hhex { bytes: out_bytes};
+            marshall_to_haskell_var(&h, out, out_len, RW);
+        },
+        Err(_e) => {
+            let h0 = Hhex { bytes: vec![0]};
+            marshall_to_haskell_var(&h0, out, out_len, RW);
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn rust_wrapper_read_sapling_witness(
+    tree: *const u8,
+    tree_len: usize,
+    out: *mut u8,
+    out_len: &mut usize
+    ){
+    let tree_in: Vec<u8> = marshall_from_haskell_var(tree, tree_len, RW);
+    let tree_reader = Cursor::new(tree_in);
+    let ct: CommitmentTree<Node, SAPLING_DEPTH> = read_commitment_tree(tree_reader).unwrap();
+    let inc_wit = IncrementalWitness::from_tree(ct);
+    let mut out_bytes: Vec<u8> = Vec::new();
+    let result = write_incremental_witness(&inc_wit, &mut out_bytes);
+    match result {
+        Ok(()) => {
+            let h = Hhex { bytes: out_bytes};
+            marshall_to_haskell_var(&h, out, out_len, RW);
+        },
+        Err(_e) => {
+            let h0 = Hhex { bytes: vec![0]};
+            marshall_to_haskell_var(&h0, out, out_len, RW);
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn rust_wrapper_read_sapling_position(
+    wit: *const u8,
+    wit_len: usize,
+    ) -> u64 {
+    let wit_in: Vec<u8> = marshall_from_haskell_var(wit, wit_len, RW);
+    let wit_reader = Cursor::new(wit_in);
+    let iw: IncrementalWitness<Node, SAPLING_DEPTH> = read_incremental_witness(wit_reader).unwrap();
+    let path = iw.path();
+    match path {
+        Some(p) => {
+            let pos = p.position();
+            return u64::from(pos);
+        },
+        None => {
+            return 0;
+        }
+    }
+}

src/C/Zcash.chs

@@ -21,6 +21,7 @@ import qualified Data.Text as T
 import Data.Word
 import Data.Int
 import Data.Structured
+import Data.HexString (HexString(..))
 import Foreign.C.Types
 import Foreign.Rust.Marshall.External
 import Foreign.Rust.Marshall.Fixed
@@ -106,6 +107,7 @@ import ZcashHaskell.Types
     , toBorshVar* `BS.ByteString'&
     , `Bool'
     , `Bool'
+    , `Word64'
     , getVarBuffer `Buffer DecodedNote'&
     }
  -> `()'
@@ -201,6 +203,27 @@ import ZcashHaskell.Types
   -> `()'
 #}
 
+{# fun unsafe rust_wrapper_read_sapling_commitment_tree as rustWrapperReadSaplingCommitmentTree
+     { toBorshVar* `BS.ByteString'&
+     , toBorshVar* `BS.ByteString'&
+     , getVarBuffer `Buffer HexString'&
+     }
+  -> `()'
+#}
+
+{# fun unsafe rust_wrapper_read_sapling_witness as rustWrapperReadSaplingWitness
+     { toBorshVar* `BS.ByteString'&
+     , getVarBuffer `Buffer HexString'&
+     }
+  -> `()'
+#}
+
+{# fun pure unsafe rust_wrapper_read_sapling_position as rustWrapperReadSaplingPosition
+     { toBorshVar* `BS.ByteString'&
+     }
+  -> `Word64'
+#}
+
 {# fun unsafe rust_wrapper_bech32_encode as rustWrapperBech32Encode
      { toBorshVar* `BS.ByteString'&
      , toBorshVar* `BS.ByteString'&

src/ZcashHaskell/Sapling.hs

@@ -19,6 +19,9 @@ module ZcashHaskell.Sapling where
 
 import C.Zcash
   ( rustWrapperIsShielded
+  , rustWrapperReadSaplingCommitmentTree
+  , rustWrapperReadSaplingPosition
+  , rustWrapperReadSaplingWitness
   , rustWrapperSaplingCheck
   , rustWrapperSaplingChgPaymentAddress
   , rustWrapperSaplingDecodeEsk
@@ -30,7 +33,7 @@ import C.Zcash
   )
 import Data.Aeson
 import qualified Data.ByteString as BS
-import Data.HexString (HexString(..), fromText, toBytes, toText)
+import Data.HexString (HexString(..), fromText, hexString, toBytes, toText)
 import Data.Word
 import Foreign.Rust.Marshall.Variable
   ( withPureBorshVarBuffer
@@ -42,8 +45,10 @@ import ZcashHaskell.Types
   , DecodedNote(..)
   , RawData(..)
   , RawTxResponse(..)
+  , SaplingCommitmentTree(..)
   , SaplingReceiver(..)
   , SaplingSpendingKey(..)
+  , SaplingWitness(..)
   , Scope(..)
   , Seed(..)
   , ShieldedOutput(..)
@@ -116,8 +121,9 @@ decodeSaplingOutputEsk ::
   -> ShieldedOutput
   -> ZcashNet
   -> Scope
+  -> Integer
   -> Maybe DecodedNote
-decodeSaplingOutputEsk key out znet scope =
+decodeSaplingOutputEsk key out znet scope pos =
   case a_value decodedAction of
     0 -> Nothing
     _ -> Just decodedAction
@@ -129,6 +135,7 @@ decodeSaplingOutputEsk key out znet scope =
         (serializeShieldedOutput out)
         (znet == MainNet)
         (scope == External)
+        (fromIntegral pos)
 
 -- | Attempts to obtain a sapling SpendingKey using a HDSeed
 genSaplingSpendingKey :: Seed -> CoinType -> Int -> Maybe SaplingSpendingKey
@@ -166,3 +173,35 @@ genSaplingInternalAddress sk =
   where
     res =
       withPureBorshVarBuffer (rustWrapperSaplingChgPaymentAddress $ getBytes sk)
+
+-- | Update a Sapling commitment tree
+updateSaplingCommitmentTree ::
+     SaplingCommitmentTree -- ^ the base tree
+  -> HexString -- ^ the new note commitment
+  -> Maybe SaplingCommitmentTree
+updateSaplingCommitmentTree tree cmu =
+  if BS.length (hexBytes updatedTree) > 1
+    then Just $ SaplingCommitmentTree updatedTree
+    else Nothing
+  where
+    updatedTree =
+      withPureBorshVarBuffer $
+      rustWrapperReadSaplingCommitmentTree
+        (hexBytes $ sapTree tree)
+        (hexBytes cmu)
+
+-- | Get the Sapling incremental witness from a commitment tree
+getSaplingWitness :: SaplingCommitmentTree -> Maybe SaplingWitness
+getSaplingWitness tree =
+  if BS.length (hexBytes wit) > 1
+    then Just $ SaplingWitness wit
+    else Nothing
+  where
+    wit =
+      withPureBorshVarBuffer $
+      rustWrapperReadSaplingWitness (hexBytes $ sapTree tree)
+
+-- | Get the Sapling note position from a witness
+getSaplingNotePosition :: SaplingWitness -> Integer
+getSaplingNotePosition =
+  fromIntegral . rustWrapperReadSaplingPosition . hexBytes . sapWit

src/ZcashHaskell/Types.hs

@@ -519,6 +519,16 @@ instance FromJSON ShieldedOutput where
       p <- obj .: "proof"
       pure $ ShieldedOutput cv cmu ephKey encText outText p
 
+-- | Type for a Sapling note commitment tree
+newtype SaplingCommitmentTree = SaplingCommitmentTree
+  { sapTree :: HexString
+  } deriving (Eq, Prelude.Show, Read)
+
+-- | Type for a Sapling incremental witness
+newtype SaplingWitness = SaplingWitness
+  { sapWit :: HexString
+  } deriving (Eq, Prelude.Show, Read)
+
 -- * Orchard
 -- | A spending key for Orchard
 newtype OrchardSpendingKey =

test/Spec.hs

@@ -50,10 +50,13 @@ import ZcashHaskell.Sapling
   , genSaplingInternalAddress
   , genSaplingPaymentAddress
   , genSaplingSpendingKey
+  , getSaplingNotePosition
+  , getSaplingWitness
   , getShieldedOutputs
   , isValidSaplingViewingKey
   , isValidShieldedAddress
   , matchSaplingAddress
+  , updateSaplingCommitmentTree
   )
 import ZcashHaskell.Transparent
 import ZcashHaskell.Types
@@ -71,6 +74,7 @@ import ZcashHaskell.Types
   , RawTxOut(..)
   , RawTxResponse(..)
   , RawZebraTx(..)
+  , SaplingCommitmentTree(..)
   , SaplingReceiver(..)
   , SaplingSpendingKey(..)
   , Scope(..)
@@ -842,22 +846,53 @@ main = do
             Nothing -> assertFailure "Couldn't decode"
             Just t' -> do
               let tb = zt_tBundle t'
-              print tb
               show tb `shouldNotBe` ""
+      describe "Sapling commitment trees" $ do
+        let tree =
+              SaplingCommitmentTree $
+              hexString
+                "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"
+        let cmu1 =
+              hexString
+                "45e47c5df6f5c5e48aa3526e977b2d1b57eda57214e36f06128008cb17b0125f"
+        let cmu2 =
+              hexString
+                "426ef44b3b22e0eeda7e4d2b62bac63966572b224e50f97ee56c9490cde4910d"
+        let tree2 =
+              hexString
+                "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"
+        it "Commitment tree is updated correctly" $ do
+          let t1 = updateSaplingCommitmentTree tree cmu1
+          t1 `shouldNotBe` Nothing
+        it "Incremental witness is generated" $ do
+          let t1 = updateSaplingCommitmentTree tree cmu1
+          case t1 of
+            Nothing -> assertFailure "Failed to append node to tree"
+            Just t -> getSaplingWitness t `shouldNotBe` Nothing
+        it "Position of note is obtained" $ do
+          let p =
+                getSaplingNotePosition <$>
+                (getSaplingWitness =<< updateSaplingCommitmentTree tree cmu1)
+          p `shouldBe` Just 129405
       describe "Extract Sapling Address - UA Valid" $ do
-        let sr = getSaplingFromUA "u14a5c4ufn9feqvxssnvscep29j5cse4gjpg0w3w5vjhafn74hg9k73xgnxqv6m255n23weggr6j97c8kdwvn4pkz7rz6my52z8248gjmr7knlw536tcurs5km7knqnzez4cywudt3q6shr553hurduvljfeqvfzgegenfjashslkz3y4ykhxel6mrjp9gsm9xk7k6kdxn9y84kccmv8l"
+        let sr =
+              getSaplingFromUA
+                "u14a5c4ufn9feqvxssnvscep29j5cse4gjpg0w3w5vjhafn74hg9k73xgnxqv6m255n23weggr6j97c8kdwvn4pkz7rz6my52z8248gjmr7knlw536tcurs5km7knqnzez4cywudt3q6shr553hurduvljfeqvfzgegenfjashslkz3y4ykhxel6mrjp9gsm9xk7k6kdxn9y84kccmv8l"
         it "Extract sapling address" $ do
           case sr of
-            Nothing -> assertFailure "UA invalid or does not contain a Sapling receiver"
+            Nothing ->
+              assertFailure "UA invalid or does not contain a Sapling receiver"
             Just t -> do
               print t
-              t `shouldBe` "zs1waxrpde36rlrjdwfhnvw030sn29lzwmvmeupd8x2uuqgypaafx7mqcy0ep8yf2xtg30n5424t60"
+              t `shouldBe`
+                "zs1waxrpde36rlrjdwfhnvw030sn29lzwmvmeupd8x2uuqgypaafx7mqcy0ep8yf2xtg30n5424t60"
       describe "Extract Sapling Address - UA Invalid" $ do
-        let sr = getSaplingFromUA "u14a5c4ufn9qfevxssnvscep29j5cse4gjpg0w3w5vjhafn74hg9k73xgnxqv6m255n23weggr6j97c8kdwvn4pkz7rz6my52z8248gjmr7knlw536tcurs5km7knqnzez4cywudt3q6shr553hurduvljfeqvfzgegenfjashslkz3y4ykhxel6mrjp9gsm9xk7k6kdxn9y84kccmv8l"
+        let sr =
+              getSaplingFromUA
+                "u14a5c4ufn9qfevxssnvscep29j5cse4gjpg0w3w5vjhafn74hg9k73xgnxqv6m255n23weggr6j97c8kdwvn4pkz7rz6my52z8248gjmr7knlw536tcurs5km7knqnzez4cywudt3q6shr553hurduvljfeqvfzgegenfjashslkz3y4ykhxel6mrjp9gsm9xk7k6kdxn9y84kccmv8l"
         it "Try to extract sapling address from invalid UA" $ do
           sr `shouldBe` Nothing
 
-
 -- | Properties
 prop_PhraseLength :: Property
 prop_PhraseLength =

zcash-haskell.cabal

@@ -5,7 +5,7 @@ cabal-version: 3.0
 -- see: https://github.com/sol/hpack
 
 name:           zcash-haskell
-version:        0.5.4.0
+version:        0.5.4.1
 synopsis:       Utilities to interact with the Zcash blockchain
 description:    Please see the README on the repo at <https://git.vergara.tech/Vergara_Tech/zcash-haskell#readme>
 category:       Blockchain