From d52de28704b45d67a296c10c02e9fc511d06d9b6 Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <andrew.kozlik@gmail.com>
Date: Tue, 30 Jun 2020 11:13:33 +0200
Subject: [PATCH] core/bitcoin: Implement BIP-322 SignatureProof container.

---
 core/src/apps/bitcoin/scripts.py | 39 ++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/core/src/apps/bitcoin/scripts.py b/core/src/apps/bitcoin/scripts.py
index 498afcc0b..77ef5d09f 100644
--- a/core/src/apps/bitcoin/scripts.py
+++ b/core/src/apps/bitcoin/scripts.py
@@ -515,6 +515,45 @@ def output_script_paytoopreturn(data: bytes) -> bytearray:
     return w
 
 
+# BIP-322: SignatureProof container for scriptSig & witness
+# ===
+# https://github.com/bitcoin/bips/blob/master/bip-0322.mediawiki
+
+
+def write_bip322_signature_proof(
+    w: Writer,
+    script_type: EnumTypeInputScriptType,
+    multisig: MultisigRedeemScriptType,
+    coin: CoinInfo,
+    public_key: bytes,
+    signature: bytes,
+) -> None:
+    script_sig = input_derive_script(
+        script_type, multisig, coin, common.SIGHASH_ALL, public_key, signature
+    )
+    if script_type in common.SEGWIT_INPUT_SCRIPT_TYPES:
+        if multisig:
+            # find the place of our signature based on the public key
+            signature_index = multisig_pubkey_index(multisig, public_key)
+            witness = witness_p2wsh(
+                multisig, signature, signature_index, common.SIGHASH_ALL
+            )
+        else:
+            witness = witness_p2wpkh(signature, public_key, common.SIGHASH_ALL)
+    else:
+        # Zero entries in witness stack.
+        witness = bytearray(b"\x00")
+
+    write_bytes_prefixed(w, script_sig)
+    w.extend(witness)
+
+
+def read_bip322_signature_proof(r: BytearrayReader) -> Tuple[bytes, bytes]:
+    script_sig = read_bytes_prefixed(r)
+    witness = r.read()
+    return script_sig, witness
+
+
 # Helpers
 # ===