msg sign: Sparrow QR compat

(cherry picked from commit a2bdfc9a58)

releases/Next-ChangeLog.md

@@ -52,6 +52,7 @@ This lists the new changes that have not yet been published in a normal release.
 
 - New Feature: Verify Signed RFC messages via BBQr
 - New Feature: Sign message from QR scan (format has to be JSON)
+- Enhancement: Sign/Verify Address in Sparrow via QR
 - Enhancement: Sign scanned Simple Text by pressing (0). Next screens query information
   about key to use. 
 - Bugfix: Properly re-draw status bar after Restore Master on COLDCARD without master seed.

shared/auth.py

@@ -305,6 +305,19 @@ def parse_msg_sign_request(data):
     subpath = ""
     addr_fmt = "p2pkh"
     is_json = False
+
+    # sparrow compat
+    if "signmessage" in data:
+        try:
+            mark, subpath, *msg_line = data.split(" ", 2)
+            assert mark == "signmessage"
+            # subpath will be verified & cleaned later
+            assert msg_line[0][:6] == "ascii:"
+            text = msg_line[0][6:]
+            return text, subpath, addr_fmt, is_json
+        except: pass
+    # ===
+
     try:
         data_dict = ujson.loads(data.strip())
         text = data_dict.get("msg", None)

shared/decoders.py

@@ -169,6 +169,10 @@ def decode_qr_result(got, expect_secret=False, expect_text=False, expect_bbqr=Fa
             return "smsg", (got,)
     except: pass
 
+    # Sparrow compat
+    if "signmessage" in got:
+        return "smsg", (got,)
+
     # try to recognize various bitcoin-related text strings...
     return decode_short_text(got)