Handle Ctrl-C in masked input

src/tests/test_seed_prompt.py

@@ -1,4 +1,5 @@
 import types
+import pytest
 from utils import seed_prompt
 
 
@@ -46,6 +47,37 @@ def test_masked_input_windows_space(monkeypatch, capsys):
     assert out.count("*") == 4
 
 
+def test_masked_input_posix_ctrl_c(monkeypatch):
+    seq = iter(["\x03"])
+    monkeypatch.setattr(seed_prompt.sys.stdin, "read", lambda n=1: next(seq))
+    monkeypatch.setattr(seed_prompt.sys.stdin, "fileno", lambda: 0)
+
+    calls: list[tuple[str, int]] = []
+    fake_termios = types.SimpleNamespace(
+        tcgetattr=lambda fd: "old",
+        tcsetattr=lambda fd, *_: calls.append(("tcsetattr", fd)),
+        TCSADRAIN=1,
+    )
+    fake_tty = types.SimpleNamespace(setraw=lambda fd: calls.append(("setraw", fd)))
+    monkeypatch.setattr(seed_prompt, "termios", fake_termios)
+    monkeypatch.setattr(seed_prompt, "tty", fake_tty)
+    monkeypatch.setattr(seed_prompt.sys, "platform", "linux", raising=False)
+
+    with pytest.raises(KeyboardInterrupt):
+        seed_prompt.masked_input("Enter: ")
+    assert calls == [("setraw", 0), ("tcsetattr", 0)]
+
+
+def test_masked_input_windows_ctrl_c(monkeypatch):
+    seq = iter(["\x03"])
+    fake_msvcrt = types.SimpleNamespace(getwch=lambda: next(seq))
+    monkeypatch.setattr(seed_prompt, "msvcrt", fake_msvcrt)
+    monkeypatch.setattr(seed_prompt.sys, "platform", "win32", raising=False)
+
+    with pytest.raises(KeyboardInterrupt):
+        seed_prompt.masked_input("Password: ")
+
+
 def test_prompt_seed_words_valid(monkeypatch):
     from mnemonic import Mnemonic