From dd7ed61939277b8e17c7b4fcc4b2d5306ff35b3e Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <andrew.kozlik@gmail.com>
Date: Sat, 16 Oct 2021 10:07:19 +0200
Subject: [PATCH] feat(core): Implement GetAddress for taproot.

---
 core/.changelog.d/1656.added.4       |  1 +
 core/src/apps/bitcoin/addresses.py   | 16 ++++++++++++++++
 core/src/apps/bitcoin/get_address.py |  5 ++++-
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 core/.changelog.d/1656.added.4

diff --git a/core/.changelog.d/1656.added.4 b/core/.changelog.d/1656.added.4
new file mode 100644
index 0000000000..b54695a7d9
--- /dev/null
+++ b/core/.changelog.d/1656.added.4
@@ -0,0 +1 @@
+Support GetAddress for Taproot addresses.
diff --git a/core/src/apps/bitcoin/addresses.py b/core/src/apps/bitcoin/addresses.py
index 9c904fc25e..4b25a10cc2 100644
--- a/core/src/apps/bitcoin/addresses.py
+++ b/core/src/apps/bitcoin/addresses.py
@@ -1,5 +1,6 @@
 from trezor import wire
 from trezor.crypto import base58, cashaddr
+from trezor.crypto.curve import bip340
 from trezor.crypto.hashlib import sha256
 from trezor.enums import InputScriptType
 from trezor.messages import MultisigRedeemScriptType
@@ -56,6 +57,15 @@ def get_address(
         # native p2wpkh
         return address_p2wpkh(node.public_key(), coin)
 
+    elif script_type == InputScriptType.SPENDTAPROOT:  # taproot
+        if not coin.taproot or not coin.bech32_prefix:
+            raise wire.ProcessError("Taproot not enabled on this coin")
+
+        if multisig is not None:
+            raise wire.ProcessError("Multisig not supported for taproot")
+
+        return address_p2tr(node.public_key(), coin)
+
     elif (
         script_type == InputScriptType.SPENDP2SHWITNESS
     ):  # p2wpkh or p2wsh nested in p2sh
@@ -130,6 +140,12 @@ def address_p2wsh(witness_script_hash: bytes, hrp: str) -> str:
     return encode_bech32_address(hrp, 0, witness_script_hash)
 
 
+def address_p2tr(pubkey: bytes, coin: CoinInfo) -> str:
+    assert coin.bech32_prefix is not None
+    output_pubkey = bip340.tweak_public_key(pubkey[1:])
+    return encode_bech32_address(coin.bech32_prefix, 1, output_pubkey)
+
+
 def address_to_cashaddr(address: str, coin: CoinInfo) -> str:
     assert coin.cashaddr_prefix is not None
     raw = base58.decode_check(address, coin.b58_hash)
diff --git a/core/src/apps/bitcoin/get_address.py b/core/src/apps/bitcoin/get_address.py
index 29fd56d3da..26723e5f12 100644
--- a/core/src/apps/bitcoin/get_address.py
+++ b/core/src/apps/bitcoin/get_address.py
@@ -52,7 +52,10 @@ async def get_address(
 
     address = addresses.get_address(msg.script_type, coin, node, msg.multisig)
     address_short = addresses.address_short(coin, address)
-    if coin.segwit and msg.script_type == InputScriptType.SPENDWITNESS:
+    if coin.segwit and msg.script_type in (
+        InputScriptType.SPENDWITNESS,
+        InputScriptType.SPENDTAPROOT,
+    ):
         address_qr = address.upper()  # bech32 address
     elif coin.cashaddr_prefix is not None:
         address_qr = address.upper()  # cashaddr address