feat: Add nested-segwit support

feat: add nested segwit support
test nested segwit digest for 1 inputs and 2 output transactions
add tests to verify nested segwit transactions
test nested segwit digest for 2 inputs and 2 output transactions

Author: rxbryan

apps/btc_family/btc_pub_key.c

@@ -204,7 +204,17 @@ static size_t btc_get_address(const uint8_t *seed,
     case NON_SEGWIT:
       hdnode_get_address(&node, g_btc_app->p2pkh_addr_ver, addr, 35);
       break;
-    // TODO: add support for taproot and segwit
+    case PURPOSE_SEGWIT:
+      ecdsa_get_address_segwit_p2sh(
+              node.public_key,
+              g_btc_app->p2sh_addr_ver,
+              node.curve->hasher_pubkey,
+              node.curve->hasher_base58,
+              addr,
+              36
+            );
+      break;
+    // TODO: add support for taproot
     default:
       break;
   }

apps/btc_family/btc_txn.c

@@ -648,11 +648,26 @@ static bool sign_input(scrip_sig_t *signatures) {
   status = true;
   for (int idx = 0; idx < btc_txn_context->metadata.input_count; idx++) {
     // generate the input digest and respective private key
-    status = btc_digest_input(btc_txn_context, idx, buffer);
     memcpy(&t_node, &node, sizeof(HDNode));
     hdnode_private_ckd(&t_node, btc_txn_context->inputs[idx].change_index);
     hdnode_private_ckd(&t_node, btc_txn_context->inputs[idx].address_index);
     hdnode_fill_public_key(&t_node);
+
+    // detect input type
+    btc_sign_txn_input_script_pub_key_t *script =
+        &btc_txn_context->inputs[idx].script_pub_key;
+    btc_script_type_e type = btc_get_script_type(script->bytes, script->size);
+    if (SCRIPT_TYPE_P2SH == type) {
+      // replace BIP16 scriptpubkey with redeemscript(P2WPKH)
+      uint8_t buf[22] = {0};
+      buf[0] = 0;   // version byte
+      buf[1] = 20;  // push 20 bytes
+      ecdsa_get_pubkeyhash(t_node.public_key, t_node.curve->hasher_pubkey, buf + 2);
+      memcpy(btc_txn_context->inputs[idx].script_pub_key.bytes, buf, 22);
+      btc_txn_context->inputs[idx].script_pub_key.size = 22;
+    }
+
+    status = btc_digest_input(btc_txn_context, idx, buffer);
     ecdsa_sign_digest(
         curve, t_node.private_key, buffer, signatures[idx].bytes, NULL, NULL);
     signatures[idx].size = btc_sig_to_script_sig(

apps/btc_family/btc_txn_helpers.c

@@ -670,7 +670,6 @@ bool btc_digest_input(const btc_txn_context_t *context,
   btc_sign_txn_input_script_pub_key_t *script =
       &context->inputs[index].script_pub_key;
   btc_script_type_e type = btc_get_script_type(script->bytes, script->size);
-
   if (SCRIPT_TYPE_P2WPKH == type) {
     // segwit digest calculation; could fail if segwit_cache not filled
     status = calculate_p2wpkh_digest(context, index, digest);