feat(core): Support 50 digit PIN and wipe code.

core/CHANGELOG.md

@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Allow decreasing the output value in RBF transactions.  [#1491]
 - Cardano: Allow stake pool registrations with zero margin.  [#1502]
 - Cardano: Assets are now shown as CIP-0014.  [#1510]
+- Support PIN of unlimited length.  [#1167]
 
 ### Deprecated
 
@@ -358,6 +359,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [#1139]: https://github.com/trezor/trezor-firmware/issues/1139
 [#1159]: https://github.com/trezor/trezor-firmware/issues/1159
 [#1165]: https://github.com/trezor/trezor-firmware/pull/1165
+[#1167]: https://github.com/trezor/trezor-firmware/issues/1167
 [#1173]: https://github.com/trezor/trezor-firmware/pull/1173
 [#1184]: https://github.com/trezor/trezor-firmware/issues/1184
 [#1188]: https://github.com/trezor/trezor-firmware/issues/1188

core/embed/extmod/modtrezorconfig/modtrezorconfig.c

@@ -66,13 +66,15 @@ STATIC mp_obj_t mod_trezorconfig_init(size_t n_args, const mp_obj_t *args) {
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_init_obj, 0, 1,
                                            mod_trezorconfig_init);
 
-/// def unlock(pin: int, ext_salt: Optional[bytes]) -> bool:
+/// def unlock(pin: str, ext_salt: Optional[bytes]) -> bool:
 ///     """
 ///     Attempts to unlock the storage with the given PIN and external salt.
 ///     Returns True on success, False on failure.
 ///     """
 STATIC mp_obj_t mod_trezorconfig_unlock(mp_obj_t pin, mp_obj_t ext_salt) {
-  uint32_t pin_i = trezor_obj_get_uint(pin);
+  mp_buffer_info_t pin_b = {0};
+  mp_get_buffer_raise(pin, &pin_b, MP_BUFFER_READ);
+
   mp_buffer_info_t ext_salt_b = {0};
   ext_salt_b.buf = NULL;
   if (ext_salt != mp_const_none) {
@@ -81,7 +83,7 @@ STATIC mp_obj_t mod_trezorconfig_unlock(mp_obj_t pin, mp_obj_t ext_salt) {
       mp_raise_msg(&mp_type_ValueError, "Invalid length of external salt.");
   }
 
-  if (sectrue != storage_unlock(pin_i, ext_salt_b.buf)) {
+  if (sectrue != storage_unlock(pin_b.buf, pin_b.len, ext_salt_b.buf)) {
     return mp_const_false;
   }
   return mp_const_true;
@@ -89,7 +91,7 @@ STATIC mp_obj_t mod_trezorconfig_unlock(mp_obj_t pin, mp_obj_t ext_salt) {
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorconfig_unlock_obj,
                                  mod_trezorconfig_unlock);
 
-/// def check_pin(pin: int, ext_salt: Optional[bytes]) -> bool:
+/// def check_pin(pin: str, ext_salt: Optional[bytes]) -> bool:
 ///     """
 ///     Check the given PIN with the given external salt.
 ///     Returns True on success, False on failure.
@@ -148,8 +150,8 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_get_pin_rem_obj,
                                  mod_trezorconfig_get_pin_rem);
 
 /// def change_pin(
-///     oldpin: int,
-///     newpin: int,
+///     oldpin: str,
+///     newpin: str,
 ///     old_ext_salt: Optional[bytes],
 ///     new_ext_salt: Optional[bytes],
 /// ) -> bool:
@@ -158,8 +160,12 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_get_pin_rem_obj,
 ///     """
 STATIC mp_obj_t mod_trezorconfig_change_pin(size_t n_args,
                                             const mp_obj_t *args) {
-  uint32_t oldpin = trezor_obj_get_uint(args[0]);
-  uint32_t newpin = trezor_obj_get_uint(args[1]);
+  mp_buffer_info_t oldpin = {0};
+  mp_get_buffer_raise(args[0], &oldpin, MP_BUFFER_READ);
+
+  mp_buffer_info_t newpin = {0};
+  mp_get_buffer_raise(args[1], &newpin, MP_BUFFER_READ);
+
   mp_buffer_info_t ext_salt_b = {0};
   const uint8_t *old_ext_salt = NULL;
   if (args[2] != mp_const_none) {
@@ -176,8 +182,8 @@ STATIC mp_obj_t mod_trezorconfig_change_pin(size_t n_args,
     new_ext_salt = ext_salt_b.buf;
   }
 
-  if (sectrue !=
-      storage_change_pin(oldpin, newpin, old_ext_salt, new_ext_salt)) {
+  if (sectrue != storage_change_pin(oldpin.buf, oldpin.len, newpin.buf,
+                                    newpin.len, old_ext_salt, new_ext_salt)) {
     return mp_const_false;
   }
   return mp_const_true;
@@ -185,13 +191,14 @@ STATIC mp_obj_t mod_trezorconfig_change_pin(size_t n_args,
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_change_pin_obj, 4,
                                            4, mod_trezorconfig_change_pin);
 
-/// def ensure_not_wipe_code(pin: int) -> None:
+/// def ensure_not_wipe_code(pin: str) -> None:
 ///     """
 ///     Wipes the device if the entered PIN is the wipe code.
 ///     """
 STATIC mp_obj_t mod_trezorconfig_ensure_not_wipe_code(mp_obj_t pin) {
-  uint32_t pin_i = trezor_obj_get_uint(pin);
-  storage_ensure_not_wipe_code(pin_i);
+  mp_buffer_info_t pin_b = {0};
+  mp_get_buffer_raise(pin, &pin_b, MP_BUFFER_READ);
+  storage_ensure_not_wipe_code(pin_b.buf, pin_b.len);
   return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorconfig_ensure_not_wipe_code_obj,
@@ -211,17 +218,21 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_has_wipe_code_obj,
                                  mod_trezorconfig_has_wipe_code);
 
 /// def change_wipe_code(
-///     pin: int,
+///     pin: str,
 ///     ext_salt: Optional[bytes],
-///     wipe_code: int,
+///     wipe_code: str,
 /// ) -> bool:
 ///     """
 ///     Change wipe code. Returns True on success, False on failure.
 ///     """
 STATIC mp_obj_t mod_trezorconfig_change_wipe_code(size_t n_args,
                                                   const mp_obj_t *args) {
-  uint32_t pin = trezor_obj_get_uint(args[0]);
-  uint32_t wipe_code = trezor_obj_get_uint(args[2]);
+  mp_buffer_info_t pin_b = {0};
+  mp_get_buffer_raise(args[0], &pin_b, MP_BUFFER_READ);
+
+  mp_buffer_info_t wipe_code_b = {0};
+  mp_get_buffer_raise(args[2], &wipe_code_b, MP_BUFFER_READ);
+
   mp_buffer_info_t ext_salt_b = {0};
   const uint8_t *ext_salt = NULL;
   if (args[1] != mp_const_none) {
@@ -231,7 +242,8 @@ STATIC mp_obj_t mod_trezorconfig_change_wipe_code(size_t n_args,
     ext_salt = ext_salt_b.buf;
   }
 
-  if (sectrue != storage_change_wipe_code(pin, ext_salt, wipe_code)) {
+  if (sectrue != storage_change_wipe_code(pin_b.buf, pin_b.len, ext_salt,
+                                          wipe_code_b.buf, wipe_code_b.len)) {
     return mp_const_false;
   }
   return mp_const_true;

core/embed/extmod/modtrezorconfig/norcow_config.h

@@ -39,6 +39,6 @@
 /*
  * Current storage version.
  */
-#define NORCOW_VERSION ((uint32_t)0x00000002)
+#define NORCOW_VERSION ((uint32_t)0x00000003)
 
 #endif

core/mocks/generated/trezorconfig.pyi

@@ -12,7 +12,7 @@ def init(
 
 
 # extmod/modtrezorconfig/modtrezorconfig.c
-def unlock(pin: int, ext_salt: Optional[bytes]) -> bool:
+def unlock(pin: str, ext_salt: Optional[bytes]) -> bool:
     """
     Attempts to unlock the storage with the given PIN and external salt.
     Returns True on success, False on failure.
@@ -20,7 +20,7 @@ def unlock(pin: int, ext_salt: Optional[bytes]) -> bool:
 
 
 # extmod/modtrezorconfig/modtrezorconfig.c
-def check_pin(pin: int, ext_salt: Optional[bytes]) -> bool:
+def check_pin(pin: str, ext_salt: Optional[bytes]) -> bool:
     """
     Check the given PIN with the given external salt.
     Returns True on success, False on failure.
@@ -57,8 +57,8 @@ def get_pin_rem() -> int:
 
 # extmod/modtrezorconfig/modtrezorconfig.c
 def change_pin(
-    oldpin: int,
-    newpin: int,
+    oldpin: str,
+    newpin: str,
     old_ext_salt: Optional[bytes],
     new_ext_salt: Optional[bytes],
 ) -> bool:
@@ -68,7 +68,7 @@ def change_pin(
 
 
 # extmod/modtrezorconfig/modtrezorconfig.c
-def ensure_not_wipe_code(pin: int) -> None:
+def ensure_not_wipe_code(pin: str) -> None:
     """
     Wipes the device if the entered PIN is the wipe code.
     """
@@ -83,9 +83,9 @@ def has_wipe_code() -> bool:
 
 # extmod/modtrezorconfig/modtrezorconfig.c
 def change_wipe_code(
-    pin: int,
+    pin: str,
     ext_salt: Optional[bytes],
-    wipe_code: int,
+    wipe_code: str,
 ) -> bool:
     """
     Change wipe code. Returns True on success, False on failure.

core/src/apps/common/request_pin.py

@@ -3,7 +3,6 @@ import utime
 import storage.sd_salt
 from trezor import config, ui, wire
 from trezor.messages import ButtonRequestType
-from trezor.pin import pin_to_int
 from trezor.ui.components.tt.pin import CANCELLED, PinDialog
 from trezor.ui.components.tt.text import Text
 from trezor.ui.popup import Popup
@@ -71,7 +70,7 @@ async def request_pin_and_sd_salt(
 ) -> Tuple[str, Optional[bytearray]]:
     if config.has_pin():
         pin = await request_pin(ctx, prompt, config.get_pin_rem(), allow_cancel)
-        config.ensure_not_wipe_code(pin_to_int(pin))
+        config.ensure_not_wipe_code(pin)
     else:
         pin = ""
 
@@ -98,7 +97,7 @@ async def verify_user_pin(
 
     if config.has_pin():
         pin = await request_pin(ctx, prompt, config.get_pin_rem(), allow_cancel)
-        config.ensure_not_wipe_code(pin_to_int(pin))
+        config.ensure_not_wipe_code(pin)
     else:
         pin = ""
 
@@ -106,7 +105,7 @@ async def verify_user_pin(
         salt = await request_sd_salt(ctx)
     except SdCardUnavailable:
         raise wire.PinCancelled("SD salt is unavailable")
-    if config.unlock(pin_to_int(pin), salt):
+    if config.unlock(pin, salt):
         _last_successful_unlock = utime.ticks_ms()
         return
     elif not config.has_pin():
@@ -116,7 +115,7 @@ async def verify_user_pin(
         pin = await request_pin(
             ctx, "Wrong PIN, enter again", config.get_pin_rem(), allow_cancel
         )
-        if config.unlock(pin_to_int(pin), salt):
+        if config.unlock(pin, salt):
             _last_successful_unlock = utime.ticks_ms()
             return
 

core/src/apps/debug/load_device.py

@@ -4,7 +4,6 @@ from trezor import config, wire
 from trezor.crypto import bip39, slip39
 from trezor.messages import BackupType
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.layouts import confirm_action, require
 
 from apps.management import backup_types
@@ -46,7 +45,7 @@ async def load_device(ctx, msg):
     storage.device.set_passphrase_enabled(msg.passphrase_protection)
     storage.device.set_label(msg.label or "")
     if msg.pin:
-        config.change_pin(pin_to_int(""), pin_to_int(msg.pin), None, None)
+        config.change_pin("", msg.pin, None, None)
 
     return Success(message="Device loaded")
 

core/src/apps/management/change_pin.py

@@ -1,7 +1,6 @@
 from storage.device import is_initialized
 from trezor import config, ui, wire
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.components.tt.text import Text
 from trezor.ui.layouts import require, show_success
 
@@ -29,7 +28,7 @@ async def change_pin(ctx: wire.Context, msg: ChangePin) -> Success:
 
     # if changing pin, pre-check the entered pin before getting new pin
     if curpin and not msg.remove:
-        if not config.check_pin(pin_to_int(curpin), salt):
+        if not config.check_pin(curpin, salt):
             await error_pin_invalid(ctx)
 
     # get new pin
@@ -39,7 +38,7 @@ async def change_pin(ctx: wire.Context, msg: ChangePin) -> Success:
         newpin = ""
 
     # write into storage
-    if not config.change_pin(pin_to_int(curpin), pin_to_int(newpin), salt, salt):
+    if not config.change_pin(curpin, newpin, salt, salt):
         if newpin:
             await error_pin_matches_wipe_code(ctx)
         else:

core/src/apps/management/change_wipe_code.py

@@ -1,7 +1,6 @@
 from storage.device import is_initialized
 from trezor import config, ui, wire
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.components.tt.text import Text
 from trezor.ui.layouts import require, show_success
 from trezor.ui.popup import Popup
@@ -30,7 +29,7 @@ async def change_wipe_code(ctx: wire.Context, msg: ChangeWipeCode) -> Success:
 
     if not msg.remove:
         # Pre-check the entered PIN.
-        if config.has_pin() and not config.check_pin(pin_to_int(pin), salt):
+        if config.has_pin() and not config.check_pin(pin, salt):
             await error_pin_invalid(ctx)
 
         # Get new wipe code.
@@ -39,7 +38,7 @@ async def change_wipe_code(ctx: wire.Context, msg: ChangeWipeCode) -> Success:
         wipe_code = ""
 
     # Write into storage.
-    if not config.change_wipe_code(pin_to_int(pin), salt, pin_to_int(wipe_code)):
+    if not config.change_wipe_code(pin, salt, wipe_code):
         await error_pin_invalid(ctx)
 
     if wipe_code:

core/src/apps/management/recovery_device/__init__.py

@@ -4,7 +4,6 @@ import storage.recovery
 from trezor import config, ui, wire, workflow
 from trezor.messages import ButtonRequestType
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.components.tt.text import Text
 
 from apps.common.confirm import require_confirm
@@ -47,14 +46,14 @@ async def recovery_device(ctx: wire.Context, msg: RecoveryDevice) -> Success:
     # for dry run pin needs to be entered
     if msg.dry_run:
         curpin, salt = await request_pin_and_sd_salt(ctx, "Enter PIN")
-        if not config.check_pin(pin_to_int(curpin), salt):
+        if not config.check_pin(curpin, salt):
             await error_pin_invalid(ctx)
 
     if not msg.dry_run:
         # set up pin if requested
         if msg.pin_protection:
             newpin = await request_pin_confirm(ctx, allow_cancel=False)
-            config.change_pin(pin_to_int(""), pin_to_int(newpin), None, None)
+            config.change_pin("", newpin, None, None)
 
         storage.device.set_passphrase_enabled(bool(msg.passphrase_protection))
         if msg.u2f_counter is not None:

core/src/apps/management/reset_device/__init__.py

@@ -6,7 +6,6 @@ from trezor.messages import BackupType
 from trezor.messages.EntropyAck import EntropyAck
 from trezor.messages.EntropyRequest import EntropyRequest
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.layouts import confirm_backup, confirm_reset_device, require
 from trezor.ui.loader import LoadingAnimation
 
@@ -43,7 +42,7 @@ async def reset_device(ctx: wire.Context, msg: ResetDevice) -> Success:
     # request and set new PIN
     if msg.pin_protection:
         newpin = await request_pin_confirm(ctx)
-        if not config.change_pin(pin_to_int(""), pin_to_int(newpin), None, None):
+        if not config.change_pin("", newpin, None, None):
             raise wire.ProcessError("Failed to set PIN")
 
     # generate and display internal entropy

core/src/apps/management/sd_protect.py

@@ -4,7 +4,6 @@ from trezor import config, ui, wire
 from trezor.crypto import random
 from trezor.messages import SdProtectOperationType
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int
 from trezor.ui.components.tt.text import Text
 from trezor.ui.layouts import require, show_success
 
@@ -66,9 +65,9 @@ async def sd_protect_enable(ctx: wire.Context, msg: SdProtect) -> Success:
 
     # Get the current PIN.
     if config.has_pin():
-        pin = pin_to_int(await request_pin(ctx, "Enter PIN", config.get_pin_rem()))
+        pin = await request_pin(ctx, "Enter PIN", config.get_pin_rem())
     else:
-        pin = pin_to_int("")
+        pin = ""
 
     # Check PIN and prepare salt file.
     salt, salt_auth_key, salt_tag = _make_salt()
@@ -107,7 +106,7 @@ async def sd_protect_disable(ctx: wire.Context, msg: SdProtect) -> Success:
     pin, salt = await request_pin_and_sd_salt(ctx, "Enter PIN")
 
     # Check PIN and remove salt.
-    if not config.change_pin(pin_to_int(pin), pin_to_int(pin), salt, None):
+    if not config.change_pin(pin, pin, salt, None):
         await error_pin_invalid(ctx)
 
     storage.device.set_sd_salt_auth_key(None)
@@ -144,7 +143,7 @@ async def sd_protect_refresh(ctx: wire.Context, msg: SdProtect) -> Success:
     new_salt, new_auth_key, new_salt_tag = _make_salt()
     await _set_salt(ctx, new_salt, new_salt_tag, stage=True)
 
-    if not config.change_pin(pin_to_int(pin), pin_to_int(pin), old_salt, new_salt):
+    if not config.change_pin(pin, pin, old_salt, new_salt):
         await error_pin_invalid(ctx)
 
     storage.device.set_sd_salt_auth_key(new_auth_key)

core/src/trezor/pin.py

@@ -4,10 +4,6 @@ if False:
     from typing import Any, Optional
 
 
-def pin_to_int(pin: str) -> int:
-    return int("1" + pin)
-
-
 _previous_progress: Optional[int] = None
 _previous_seconds: Optional[int] = None
 keepalive_callback: Any = None

core/src/trezor/ui/components/tt/pin.py

@@ -41,16 +41,40 @@ class PinInput(ui.Component):
             self.repaint = False
 
     def render_pin(self) -> None:
-        display.bar(0, 0, ui.WIDTH, 50, ui.BG)
-        count = len(self.pin)
+        MAX_LENGTH = const(14)  # maximum length of displayed PIN
+        CONTD_MARK = "<"
         BOX_WIDTH = const(240)
         DOT_SIZE = const(10)
-        PADDING = const(14)
+        PADDING = const(4)
         RENDER_Y = const(20)
-        render_x = (BOX_WIDTH - count * PADDING) // 2
+        TWITCH = const(3)
+
+        display.bar(0, 0, ui.WIDTH, 50, ui.BG)
+
+        if len(self.pin) > MAX_LENGTH:
+            contd_width = display.text_width(CONTD_MARK, ui.BOLD) + PADDING
+            twitch = TWITCH * (len(self.pin) % 2)
+        else:
+            contd_width = 0
+            twitch = 0
+
+        count = min(len(self.pin), MAX_LENGTH)
+        render_x = (BOX_WIDTH - count * (DOT_SIZE + PADDING) - contd_width) // 2
+
+        if contd_width:
+            display.text(
+                render_x, RENDER_Y + DOT_SIZE, CONTD_MARK, ui.BOLD, ui.GREY, ui.BG
+            )
+
         for i in range(0, count):
             display.bar_radius(
-                render_x + i * PADDING, RENDER_Y, DOT_SIZE, DOT_SIZE, ui.GREY, ui.BG, 4
+                render_x + contd_width + twitch + i * (DOT_SIZE + PADDING),
+                RENDER_Y,
+                DOT_SIZE,
+                DOT_SIZE,
+                ui.GREY,
+                ui.BG,
+                4,
             )
 
     def render_prompt(self) -> None:
@@ -82,7 +106,7 @@ class PinDialog(ui.Layout):
         prompt: str,
         subprompt: Optional[str],
         allow_cancel: bool = True,
-        maxlength: int = 9,
+        maxlength: int = 50,
     ) -> None:
         self.maxlength = maxlength
         self.input = PinInput(prompt, subprompt, "")

core/tests/test_storage.py

@@ -1,5 +1,4 @@
 from common import *
-from trezor.pin import pin_to_int
 from trezor import config
 from storage import device
 

core/tests/test_trezor.config.py

@@ -1,7 +1,6 @@
 from common import *
 
 from trezor.crypto import random
-from trezor.pin import pin_to_int
 
 from trezor import config
 
@@ -27,7 +26,7 @@ class TestConfig(unittest.TestCase):
     def test_wipe(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock('', None), True)
         config.set(1, 1, b'hello')
         config.set(1, 2, b'world')
         v0 = config.get(1, 1)
@@ -44,7 +43,7 @@ class TestConfig(unittest.TestCase):
         for _ in range(128):
             config.init()
             config.wipe()
-            self.assertEqual(config.unlock(pin_to_int(''), None), True)
+            self.assertEqual(config.unlock('', None), True)
             appid, key = random_entry()
             value = random.bytes(16)
             config.set(appid, key, value)
@@ -58,7 +57,7 @@ class TestConfig(unittest.TestCase):
     def test_public(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock('', None), True)
 
         appid, key = random_entry()
 
@@ -84,20 +83,46 @@ class TestConfig(unittest.TestCase):
     def test_change_pin(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
-        with self.assertRaises(RuntimeError):
-            config.set(PINAPP, PINKEY, b'value')
-        self.assertEqual(config.change_pin(pin_to_int('000'), pin_to_int('666'), None, None), False)
-        self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000'), None, None), True)
-        self.assertEqual(config.get(PINAPP, PINKEY), None)
+        self.assertTrue(config.unlock('', None))
         config.set(1, 1, b'value')
-        config.init()
-        self.assertEqual(config.unlock(pin_to_int('000'), None), True)
-        config.change_pin(pin_to_int('000'), pin_to_int(''), None, None)
-        config.init()
-        self.assertEqual(config.unlock(pin_to_int('000'), None), False)
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
-        self.assertEqual(config.get(1, 1), b'value')
+        PINS = ('123', '123', 'Trezor T', '3141592653589793238462643383279502884197', '')
+        old_pin = ''
+        for new_pin in PINS:
+            self.assertTrue(config.unlock(old_pin, None))
+
+            # The APP namespace which is reserved for storage related values is inaccessible even
+            # when unlocked.
+            with self.assertRaises(RuntimeError):
+                config.set(PINAPP, PINKEY, b'value')
+
+            self.assertTrue(config.change_pin(old_pin, new_pin, None, None))
+
+            # Old PIN cannot be used to change the current PIN.
+            if old_pin != new_pin:
+                self.assertFalse(config.change_pin(old_pin, '666', None, None))
+
+            # Storage remains unlocked.
+            self.assertEqual(config.get(1, 1), b'value')
+
+            # The APP namespace which is reserved for storage related values is inaccessible even
+            # when unlocked.
+            self.assertEqual(config.get(PINAPP, PINKEY), None)
+
+            # Old PIN cannot be used to unlock storage.
+            if old_pin != new_pin:
+                config.init()
+                self.assertFalse(config.unlock(old_pin, None))
+                self.assertEqual(config.get(1, 1), None)
+                with self.assertRaises(RuntimeError):
+                    config.set(1, 1, b'new value')
+
+            # New PIN unlocks the storage.
+            self.assertTrue(config.unlock(new_pin, None))
+            self.assertEqual(config.get(1, 1), b'value')
+
+            # Lock the storage.
+            config.init()
+            old_pin = new_pin
 
     def test_change_sd_salt(self):
         salt1 = b"0123456789abcdef0123456789abcdef"
@@ -106,37 +131,37 @@ class TestConfig(unittest.TestCase):
         # Enable PIN and SD salt.
         config.init()
         config.wipe()
-        self.assertTrue(config.unlock(pin_to_int(''), None))
+        self.assertTrue(config.unlock('', None))
         config.set(1, 1, b'value')
-        self.assertFalse(config.change_pin(pin_to_int(''), pin_to_int(''), salt1, None))
-        self.assertTrue(config.change_pin(pin_to_int(''), pin_to_int('000'), None, salt1))
+        self.assertFalse(config.change_pin('', '', salt1, None))
+        self.assertTrue(config.change_pin('', '000', None, salt1))
         self.assertEqual(config.get(1, 1), b'value')
 
         # Disable PIN and change SD salt.
         config.init()
-        self.assertFalse(config.unlock(pin_to_int('000'), None))
+        self.assertFalse(config.unlock('000', None))
         self.assertIsNone(config.get(1, 1))
-        self.assertTrue(config.unlock(pin_to_int('000'), salt1))
-        self.assertTrue(config.change_pin(pin_to_int('000'), pin_to_int(''), salt1, salt2))
+        self.assertTrue(config.unlock('000', salt1))
+        self.assertTrue(config.change_pin('000', '', salt1, salt2))
         self.assertEqual(config.get(1, 1), b'value')
 
         # Disable SD salt.
         config.init()
-        self.assertFalse(config.unlock(pin_to_int('000'), salt2))
+        self.assertFalse(config.unlock('000', salt2))
         self.assertIsNone(config.get(1, 1))
-        self.assertTrue(config.unlock(pin_to_int(''), salt2))
-        self.assertTrue(config.change_pin(pin_to_int(''), pin_to_int(''), salt2, None))
+        self.assertTrue(config.unlock('', salt2))
+        self.assertTrue(config.change_pin('', '', salt2, None))
         self.assertEqual(config.get(1, 1), b'value')
 
         # Check that PIN and SD salt are disabled.
         config.init()
-        self.assertTrue(config.unlock(pin_to_int(''), None))
+        self.assertTrue(config.unlock('', None))
         self.assertEqual(config.get(1, 1), b'value')
 
     def test_set_get(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock('', None), True)
         for _ in range(32):
             appid, key = random_entry()
             value = random.bytes(128)
@@ -147,7 +172,7 @@ class TestConfig(unittest.TestCase):
     def test_compact(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock('', None), True)
         appid, key = 1, 1
         for _ in range(259):
             value = random.bytes(259)
@@ -158,7 +183,7 @@ class TestConfig(unittest.TestCase):
     def test_get_default(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock('', None), True)
         for _ in range(128):
             appid, key = random_entry()
             value = config.get(appid, key)