core/bitcoin: Clarify hash_type vs. sighash_type terminology.

core/src/apps/bitcoin/scripts.py

@@ -137,10 +137,10 @@ def bip143_derive_script_code(txi: TxInputType, pubkeyhash: bytes) -> bytearray:
 
 
 def input_script_p2pkh_or_p2sh(
-    pubkey: bytes, signature: bytes, sighash: int
+    pubkey: bytes, signature: bytes, hash_type: int
 ) -> bytearray:
     w = empty_bytearray(5 + len(signature) + 1 + 5 + len(pubkey))
-    append_signature(w, signature, sighash)
+    append_signature(w, signature, hash_type)
     append_pubkey(w, pubkey)
     return w
 
@@ -264,10 +264,10 @@ def input_script_p2wsh_in_p2sh(script_hash: bytes) -> bytearray:
 # ===
 
 
-def witness_p2wpkh(signature: bytes, pubkey: bytes, sighash: int) -> bytearray:
+def witness_p2wpkh(signature: bytes, pubkey: bytes, hash_type: int) -> bytearray:
     w = empty_bytearray(1 + 5 + len(signature) + 1 + 5 + len(pubkey))
     write_bitcoin_varint(w, 0x02)  # num of segwit items, in P2WPKH it's always 2
-    write_signature_prefixed(w, signature, sighash)
+    write_signature_prefixed(w, signature, hash_type)
     write_bytes_prefixed(w, pubkey)
     return w
 
@@ -297,7 +297,7 @@ def witness_p2wsh(
     multisig: MultisigRedeemScriptType,
     signature: bytes,
     signature_index: int,
-    sighash: int,
+    hash_type: int,
 ) -> bytearray:
     # get other signatures, stretch with None to the number of the pubkeys
     signatures = multisig.signatures + [None] * (
@@ -321,7 +321,7 @@ def witness_p2wsh(
     # length of the result
     total_length = 1 + 1  # number of items, OP_FALSE
     for s in signatures:
-        total_length += 1 + len(s) + 1  # length, signature, sighash
+        total_length += 1 + len(s) + 1  # length, signature, hash_type
     total_length += 1 + redeem_script_length  # length, script
 
     w = empty_bytearray(total_length)
@@ -333,7 +333,7 @@ def witness_p2wsh(
     write_bitcoin_varint(w, 0)
 
     for s in signatures:
-        write_signature_prefixed(w, s, sighash)  # size of the witness included
+        write_signature_prefixed(w, s, hash_type)  # size of the witness included
 
     # redeem script
     write_bitcoin_varint(w, redeem_script_length)
@@ -379,7 +379,7 @@ def input_script_multisig(
     multisig: MultisigRedeemScriptType,
     signature: bytes,
     signature_index: int,
-    sighash: int,
+    hash_type: int,
     coin: CoinInfo,
 ) -> bytearray:
     signatures = multisig.signatures  # other signatures
@@ -396,7 +396,7 @@ def input_script_multisig(
     if utils.BITCOIN_ONLY or not coin.decred:
         total_length += 1  # OP_FALSE
     for s in signatures:
-        total_length += 1 + len(s) + 1  # length, signature, sighash
+        total_length += 1 + len(s) + 1  # length, signature, hash_type
     total_length += 1 + redeem_script_length  # length, script
 
     w = empty_bytearray(total_length)
@@ -409,7 +409,7 @@ def input_script_multisig(
 
     for s in signatures:
         if len(s):
-            append_signature(w, s, sighash)
+            append_signature(w, s, hash_type)
 
     # redeem script
     write_op_push(w, redeem_script_length)
@@ -519,16 +519,16 @@ def output_script_paytoopreturn(data: bytes) -> bytearray:
 # ===
 
 
-def write_signature_prefixed(w: Writer, signature: bytes, sighash: int) -> None:
+def write_signature_prefixed(w: Writer, signature: bytes, hash_type: int) -> None:
     write_bitcoin_varint(w, len(signature) + 1)
     write_bytes_unchecked(w, signature)
-    w.append(sighash)
+    w.append(hash_type)
 
 
-def append_signature(w: Writer, signature: bytes, sighash: int) -> None:
+def append_signature(w: Writer, signature: bytes, hash_type: int) -> None:
     write_op_push(w, len(signature) + 1)
     write_bytes_unchecked(w, signature)
-    w.append(sighash)
+    w.append(hash_type)
 
 
 def append_pubkey(w: Writer, pubkey: bytes) -> None:

core/src/apps/bitcoin/sign_tx/bitcoin.py

@@ -250,12 +250,12 @@ class Bitcoin:
             signature_index = multisig.multisig_pubkey_index(txi.multisig, public_key)
             self.serialized_tx.extend(
                 scripts.witness_p2wsh(
-                    txi.multisig, signature, signature_index, self.get_hash_type()
+                    txi.multisig, signature, signature_index, self.get_hash_type(txi)
                 )
             )
         else:
             self.serialized_tx.extend(
-                scripts.witness_p2wpkh(signature, public_key, self.get_hash_type())
+                scripts.witness_p2wpkh(signature, public_key, self.get_hash_type(txi))
             )
 
     async def sign_nonsegwit_input(self, i_sign: int) -> None:
@@ -307,7 +307,7 @@ class Bitcoin:
             self.write_tx_output(h_sign, txo, script_pubkey)
 
         writers.write_uint32(h_sign, self.tx.lock_time)
-        writers.write_uint32(h_sign, self.get_hash_type())
+        writers.write_uint32(h_sign, self.get_sighash_type(txi_sign))
 
         # check the control digests
         if self.h_confirmed.get_digest() != h_check.get_digest():
@@ -382,9 +382,16 @@ class Bitcoin:
     # Tx Helpers
     # ===
 
-    def get_hash_type(self) -> int:
+    def get_sighash_type(self, txi: TxInputType) -> int:
         return _SIGHASH_ALL
 
+    def get_hash_type(self, txi: TxInputType) -> int:
+        """ Return the nHashType flags."""
+        # The nHashType is the 8 least significant bits of the sighash type.
+        # Some coins set the 24 most significant bits of the sighash type to
+        # the fork ID value.
+        return self.get_sighash_type(txi) & 0xFF
+
     def write_tx_input(
         self, w: writers.Writer, txi: TxInputType, script: bytes
     ) -> None:
@@ -470,7 +477,7 @@ class Bitcoin:
             txi.script_type,
             txi.multisig,
             self.coin,
-            self.get_hash_type(),
+            self.get_hash_type(txi),
             pubkey,
             signature,
         )
@@ -535,7 +542,7 @@ class Bitcoin:
         writers.write_uint32(h_preimage, self.tx.lock_time)
 
         # nHashType
-        writers.write_uint32(h_preimage, self.get_hash_type())
+        writers.write_uint32(h_preimage, self.get_sighash_type(txi))
 
         return writers.get_tx_hash(h_preimage, double=self.coin.sign_hash_double)
 

core/src/apps/bitcoin/sign_tx/bitcoinlike.py

@@ -46,8 +46,8 @@ class Bitcoinlike(Bitcoin):
         if not self.coin.negative_fee:
             super().on_negative_fee()
 
-    def get_hash_type(self) -> int:
+    def get_sighash_type(self, txi: TxInputType) -> int:
-        hashtype = super().get_hash_type()
+        hashtype = super().get_sighash_type(txi)
         if self.coin.fork_id is not None:
             hashtype |= (self.coin.fork_id << 8) | _SIGHASH_FORKID
         return hashtype

core/src/apps/bitcoin/sign_tx/zcash.py

@@ -117,7 +117,7 @@ class Overwintered(Bitcoinlike):
             # 8. expiryHeight
             write_uint32(h_preimage, self.tx.expiry)
             # 9. nHashType
-            write_uint32(h_preimage, self.get_hash_type())
+            write_uint32(h_preimage, self.get_sighash_type(txi))
         elif self.tx.version == 4:
             zero_hash = b"\x00" * TX_HASH_SIZE
             # 6. hashJoinSplits
@@ -133,7 +133,7 @@ class Overwintered(Bitcoinlike):
             # 11. valueBalance
             write_uint64(h_preimage, 0)
             # 12. nHashType
-            write_uint32(h_preimage, self.get_hash_type())
+            write_uint32(h_preimage, self.get_sighash_type(txi))
         else:
             raise wire.DataError("Unsupported version for overwintered transaction")