firmware/shared/seed.py
2022-04-14 14:00:09 -04:00

961 lines
28 KiB
Python

# (c) Copyright 2018 by Coinkite Inc. This file is covered by license found in COPYING-CC.
#
# seed.py - bip39 seeds and words
#
# references:
# - <https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki>
# - <https://iancoleman.io/bip39/#english>
# - zero values:
# - 'abandon' * 23 + 'art'
# - 'abandon' * 17 + 'agent'
# - 'abandon' * 11 + 'about'
#
from menu import MenuItem, MenuSystem
from utils import pop_count, xfp2str
import ngu, uctypes, bip39, random, version
from uhashlib import sha256
from ux import ux_show_story, the_ux, ux_dramatic_pause, ux_confirm, show_qr_code
from ux import PressRelease
from pincodes import AE_SECRET_LEN, AE_LONG_SECRET_LEN
from actions import goto_top_menu
from stash import SecretStash, SensitiveValues
from ubinascii import hexlify as b2a_hex
from pwsave import PassphraseSaver
from glob import settings
from pincodes import pa
# seed words lengths we support: 24=>256 bits, and recommended
VALID_LENGTHS = (24, 18, 12)
# bit flag that means "also include bare prefix as a valid word"
_PREFIX_MARKER = const(1<<26)
def letter_choices(sofar='', depth=0, thres=5):
# make a list of word completions based on indicated prefix
if not sofar:
# all letters:
# - except 'x' which isn't used in the wordlist.
# - and q- which is really qu-, because English.
return [('%s-' % chr(97+i)) if i != 16 else 'qu-' for i in range(26) if i != 23]
exact, nexts, matched = bip39.next_char(sofar)
#print("[%d] %s => x=%r n=%r m=%r" % (depth, sofar, exact, nexts, matched))
if not nexts:
# no more choices; done
return [matched]
rv = []
if exact:
# ie: "act" plus "action", "actor"
rv.append(sofar)
if len(nexts) == 1 and matched:
# aba => abandon (unambig first 3 chars)
# but not: age => age, agent (abig first 3)
rv.append(matched)
else:
for w in nexts:
rv.append(sofar + w + '-')
# replace bab- => baby and other cases where prefix is unique
# - doesn't grow menu length
if len(sofar) >= 2:
for n, w in enumerate(rv):
if w[-1] != '-': continue
exact, nexts, matched = bip39.next_char(w[:-1])
if matched:
rv[n] = matched
if len(rv) <= thres:
if depth == 0:
# examples:
# z => ze- and zo- ... better if all 4 z-words are shown
# y => 6 choices
# - above thres=5, we get menus w/60+ entries
# - recurse only one level also to keep size down
a = []
for i in rv:
if i[-1] != '-':
a.append(i)
else:
a.extend(letter_choices(i[:-1], depth+1))
return a
return rv
'''
# 100% working test code (keep)
thres=2 => min/max/avg = 2 / 20 / 4.221338 nodes=628
thres=3 => min/max/avg = 2 / 20 / 4.371667 nodes=600
thres=4 => min/max/avg = 2 / 31 / 4.593250 nodes=563
thres=5 => min/max/avg = 2 / 34 / 4.882917 nodes=521
thres=6 => min/max/avg = 2 / 58 / 5.397826 nodes=460
thres=7 => min/max/avg = 2 / 61 / 5.618721 nodes=438
thres=8 => min/max/avg = 2 / 61 / 5.793839 nodes=422
thres=9 => min/max/avg = 2 / 66 / 5.485588 nodes=451
def test_lc():
for thres in range(2, 10):
terms = set()
todo = set(letter_choices(''))
sizes = []
while todo:
w = todo.pop()
assert w not in terms
if w[-1] == '-':
h = letter_choices(w[:-1], thres=thres)
assert len(h) == len(set(h))
sizes.append(len(h))
todo.update(h)
else:
terms.add(w)
assert len(terms) == 2048
print("thres=%d => min/max/avg = %d / %d / %f nodes=%d" %
(thres, min(sizes), max(sizes), sum(sizes)/len(sizes), len(sizes)))
'''
class WordNestMenu(MenuSystem):
# singleton (cls level) vars
words = []
target_words = None
has_checksum = True
done_cb = None
def __init__(self, num_words=None, has_checksum=True, done_cb=None, items=None, is_commit=False):
if num_words is not None:
WordNestMenu.target_words = num_words
WordNestMenu.has_checksum = has_checksum
WordNestMenu.words = []
WordNestMenu.done_cb = done_cb or self.all_done
is_commit = True
if not items:
items = [MenuItem(i, menu=self.next_menu) for i in letter_choices()]
self.is_commit = is_commit
super(WordNestMenu, self).__init__(items)
@staticmethod
async def next_menu(self, idx, choice):
words = WordNestMenu.words
cls = self.__class__
if choice.label[-1] == '-':
ch = letter_choices(choice.label[0:-1])
return cls(items=[MenuItem(i, menu=self.next_menu) for i in ch])
# terminal choice, start next word
words.append(choice.label)
assert len(words) <= self.target_words
if len(words) == 23 and self.has_checksum:
# we can provide final 8 choices, but only for 24-word case
final_words = list(bip39.a2b_words_guess(words))
async def picks_chk_word(s, idx, choice):
# they picked final word, the word includes valid checksum bits
words.append(choice.label)
await cls.done_cb(words.copy())
items = [MenuItem(w, f=picks_chk_word) for w in final_words]
items.append(MenuItem('(none above)', f=self.explain_error))
return cls(is_commit=True, items=items)
# add a few top-items in certain cases
if len(words) == self.target_words:
if self.has_checksum:
try:
bip39.a2b_words(' '.join(words))
correct = True
except ValueError:
correct = False
else:
correct = True
# they have checksum right, so they are certainly done.
if correct:
# they are done, don't force them to do any more!
return await cls.done_cb(words.copy())
else:
# give them a chance to confirm and/or start over
return cls(is_commit=True, items = [
MenuItem('(INCORRECT)', f=self.explain_error),
MenuItem('(start over)', f=self.start_over)])
# pop stack to reset depth, and start again at a- .. z-
cls.pop_all()
return cls(items=None, is_commit=True)
@classmethod
def pop_all(cls):
while isinstance(the_ux.top_of_stack(), cls):
the_ux.pop()
def on_cancel(self):
# user pressed cancel on a menu (so he's going upwards)
# - if it's a step where we added to the word list, undo that.
# - but keep them in our system until:
# - when the word list is empty and they cancel, stop
words = WordNestMenu.words
if self.is_commit and words:
words.pop()
# replace the menu we are show w/ top-level (a-) menu
the_ux.pop()
nxt = WordNestMenu(is_commit=True)
the_ux.push(nxt)
else:
the_ux.pop()
@staticmethod
async def all_done(new_words):
# save the new seed value
set_seed_value(new_words)
# clear menu stack
goto_top_menu(first_time=True)
return None
async def explain_error(self, *a):
await ux_show_story('''\
You've got a mistake in your words. We know because the checksum does not \
verify. It's probably best to start over again, but you can back out \
individual words if you wish.''')
async def start_over(self, *a):
# pop everything we've done off the stack
self.pop_all()
# begin again, empty but same settings
self.words = []
the_ux.push(self.__class__(num_words=WordNestMenu.target_words))
def tr_label(self):
return 'Word'
def late_draw(self, dis):
# add an overlay with "word N" in small text, top right.
from display import FontTiny
count = len(self.words)
if count >= self.target_words:
# on final DONE/incorrect screen
return
dis.progress_bar(count / self.target_words)
count += 1
invert = (self.cursor == self.ypos)
y = 6
dis.text(-8, y-4, "%d" % count, invert=invert)
dis.text(-18-(6 if count >= 10 else 0), y, self.tr_label(), FontTiny, invert=invert)
async def show_words(words, prompt=None, escape=None, extra=''):
msg = (prompt or 'Record these %d secret words!\n') % len(words)
msg += '\n'.join('%2d: %s' % (i+1, w) for i,w in enumerate(words))
msg += '\n\nPlease check and double check your notes. There will be a test!'
if version.has_fatram:
escape = (escape or '') + '1'
extra += 'Press 1 to view as QR Code. '
if extra:
msg += '\n\n'
msg += extra
while 1:
ch = await ux_show_story(msg, escape=escape, sensitive=True)
if ch == '1':
await show_qr_code(' '.join(w[0:4] for w in words), True)
continue
break
return ch
async def add_dice_rolls(count, seed, judge_them):
from glob import dis
from display import FontTiny, FontLarge
md = sha256(seed)
pr = PressRelease()
# fixed parts of screen
dis.clear()
y = 38
dis.text(0, y, "Press 1-6 for each dice"); y += 13
dis.text(0, y, "roll to mix in.")
dis.save()
while 1:
# Note: cannot scroll this msg because 5=up arrow
dis.restore()
dis.text(None, 0, '%d rolls' % count, FontLarge)
hx = str(b2a_hex(md.digest()), 'ascii')
dis.text(0, 20, hx[0:32], FontTiny)
dis.text(0, 20+7, hx[32:], FontTiny)
dis.show()
ch = await pr.wait()
if ch in '123456':
count += 1
dis.restore()
dis.text(None, 0, '%d rolls' % count, FontLarge)
dis.show()
# this is slow enough to see
md.update(ch)
elif ch == 'x':
# Because the change (roll) has already been applied,
# only let them abort if it's early still
if count < 10 and judge_them:
return 0, seed
elif ch == 'y':
if count < 99 and judge_them:
if not count:
return 0, seed
ok = await ux_confirm('''\
You only provided %d dice rolls, and each roll adds only 2.585 bits of entropy. \
For 128-bit security, which is considered the minimum, you need 50 rolls, and \
for 256-bits of security, 99 rolls.''' % count)
if not ok: continue
break
if count:
seed = md.digest()
return count, seed
async def new_from_dice(nwords):
# Use lots of (D6) dice rolls to create seed entropy.
# Note: only 2.585 bits of entropy per roll, so need lots!
# 50 => 128bits, 99 => 256bits
seed = b''
count = 0
count, seed = await add_dice_rolls(count, seed, True)
if count == 0: return
await approve_word_list(seed, nwords)
async def make_new_wallet(nwords):
# Pick a new random seed.
await ux_dramatic_pause('Generating...', 3)
# starting point
seed = random.bytes(32)
assert len(set(seed)) > 4 # TRNG failure
# hash to mitigate possible bias in TRNG
seed = ngu.hash.sha256s(seed)
await approve_word_list(seed, nwords)
async def approve_word_list(seed, nwords):
# Force the user to write the seeds words down, give a quiz, then save them.
# LESSON LEARNED: if the user is writting down the words, as we have
# vividly instructed, then it's a big deal to lose those words and have to start
# over. So confirm that action, and don't volunteer it.
if nwords == 12:
seed = seed[0:16]
words = bip39.b2a_words(seed).split(' ')
assert len(words) == nwords
while 1:
# show the seed words
ch = await show_words(words, escape='46',
extra='Press 4 to add some dice rolls into the mix. ')
if ch == 'x':
# user abort, but confirm it!
if await ux_confirm("Throw away those words and stop this process?"):
return
else:
continue
if ch == '4':
# dice roll mode
count, new_seed = await add_dice_rolls(0, seed, False)
if count:
seed = new_seed[0:16] if nwords == 12 else new_seed
words = bip39.b2a_words(seed).split(' ')
continue
if ch == '6':
# wants to skip the quiz (undocumented)
if await ux_confirm("Skipping the quiz means you might have "
"recorded the seed wrong and will be crying later."):
break
# Perform a test, to check they wrote them down
ch = await word_quiz(words)
if ch == 'x':
# user abort quiz
if await ux_confirm("Throw away those words and stop this process? Press X to see the word list again and restart the quiz."):
return
# show the words again, but don't change them
continue
# quiz passed
break
# Done!
set_seed_value(words)
# send them to home menu, now with a wallet enabled
goto_top_menu(first_time=True)
def set_seed_value(words=None, encoded=None):
# Save the seed words into secure element, and reboot. BIP-39 password
# is not set at this point (empty string)
if words:
bip39.a2b_words(words) # checksum check
# map words to bip39 wordlist indices
data = [bip39.wordlist_en.index(w) for w in words]
# map to packed binary representation.
val = 0
for v in data:
val <<= 11
val |= v
# remove the checksum part
vlen = (len(words) * 4) // 3
val >>= (len(words) // 3)
# convert to bytes
seed = val.to_bytes(vlen, 'big')
assert len(seed) == vlen
# encode it for our limited secret space
nv = SecretStash.encode(seed_phrase=seed)
else:
nv = encoded
from glob import dis
try:
dis.fullscreen('Applying...')
dis.busy_bar(True)
pa.change(new_secret=nv)
# re-read settings since key is now different
# - also captures xfp, xpub at this point
pa.new_main_secret(nv)
# check and reload secret
pa.reset()
pa.login()
finally:
dis.busy_bar(False)
def set_bip39_passphrase(pw):
# apply bip39 passphrase for now (volatile)
# takes a bit, so show something
from glob import dis
dis.fullscreen("Working...")
# set passphrase
import stash
stash.bip39_passphrase = pw
# capture updated XFP
with stash.SensitiveValues() as sv:
# can't do it without original seed words (late, but caller has checked)
assert sv.mode == 'words'
sv.capture_xpub()
# Might need to bounce the USB connection, because our pubkey has changed,
# altho if they have already picked a shared session key, no need, and
# would only affect MitM test, which has already been done.
async def remember_bip39_passphrase():
# Compute current xprv and switch to using that as root secret.
import stash
from glob import dis
dis.fullscreen('Check...')
with stash.SensitiveValues() as sv:
nv = SecretStash.encode(xprv=sv.node)
# Important: won't write new XFP to nvram if pw still set
stash.bip39_passphrase = ''
dis.fullscreen('Saving...')
pa.change(new_secret=nv)
# re-read settings since key is now different
# - also captures xfp, xpub at this point
pa.new_main_secret(nv)
# check and reload secret
pa.reset()
pa.login()
def clear_seed():
from glob import dis
import utime, callgate
dis.fullscreen('Clearing...')
dis.busy_bar(True)
# clear settings associated with this key, since it will be no more
settings.blank()
if version.mk_num >= 4:
callgate.fast_wipe(True)
# NOT REACHED
else:
# save a blank secret (all zeros is a special case, detected by bootloader)
nv = bytes(AE_SECRET_LEN)
pa.change(new_secret=nv)
if version.has_608:
# wipe the long secret too
nv = bytes(AE_LONG_SECRET_LEN)
pa.ls_change(nv)
dis.busy_bar(False)
dis.fullscreen('Reboot...')
utime.sleep(1)
# security: need to reboot to really be sure to clear the secrets from main memory.
from machine import reset
reset()
async def word_quiz(words, limited=None, title='Word %d is?'):
# Perform a test, to check they wrote them down
# Return X if they cancel early.
# Can just pick a subset # of words, with limited arg.
wl = len(words) # 24 or 12, etc.
if limited is not None:
# truncate to some N randomly-selected words in the list
# and always the last word
order = list(range(wl-1))
random.shuffle(order)
order = order[0:limited-1]
order.append(wl-1)
else:
order = list(range(wl))
random.shuffle(order)
for o in order:
# always 3 choices: right answer, wrong from correct set, random word
right = words[o]
choices = [right]
while 1:
n = words[random.randbelow(wl)]
if n in choices: continue
choices.append(n)
break
while 1:
n = bip39.wordlist_en[random.randbelow(0x800)]
if n in choices: continue
choices.append(n)
break
while 1:
random.shuffle(choices)
msg = '\n'.join(' %d: %s' % (i+1, choices[i]) for i in range(3))
msg += '\n\nWhich word is right?\n\nX to give up, OK to see all the words again.'
ch = await ux_show_story(msg, title=title % (o+1), escape='123', sensitive=True)
if ch == 'x':
# user abort
return 'x'
elif ch == 'y':
await show_words(words)
continue
if ch in '123':
n = ord(ch) - ord('1')
if choices[n] == right:
break
await ux_dramatic_pause('Wrong!', 2)
return
pp_sofar = ''
class PassphraseMenu(MenuSystem):
# Collect up to 100 chars as a BIP-39 passphrase
# singleton (cls level) vars
done_cb = None
def __init__(self, done_cb=None, items=None):
global pp_sofar
pp_sofar = ''
items = [
# xxxxxxxxxxxxxxxx
MenuItem('Edit Phrase', f=self.view_edit_phrase),
MenuItem('Add Word', menu=self.word_menu),
MenuItem('Add Numbers', f=self.add_numbers),
MenuItem('Clear All', f=self.empty_phrase),
MenuItem('APPLY', f=self.done_apply),
MenuItem('CANCEL', f=self.done_cancel),
]
try:
saved = PassphraseSaver().make_menu()
if saved:
items.insert(0, MenuItem('Restore Saved', menu=saved))
except:
# don't want bugs/corrupt files to make rest of menu inaccessible
pass
super(PassphraseMenu, self).__init__(items)
def on_cancel(self):
# zip to cancel item when they fail to exit via X button
self.goto_idx(self.count - 1)
async def word_menu(self, *a):
return SingleWordMenu()
async def add_numbers(self, *a):
# collect a series of digits
from glob import dis
from display import FontTiny, FontSmall
global pp_sofar
# allow key repeat on X only
press = PressRelease('1234567890y')
footer = "X to DELETE, or OK when DONE."
lx = 6
y = 16
here = ''
dis.clear()
dis.text(None, -1, footer, FontTiny)
dis.save()
while 1:
dis.restore()
# text centered
msg = here
by = y
bx = dis.text(lx, y, msg[0:16])
dis.text(lx, y-9, str(pp_sofar, 'ascii').replace(' ', '_'), FontTiny)
if len(msg) > 16:
# second line when needed (left just)
by += 15
bx = dis.text(lx, by, msg[16:])
if len(here) < 32:
dis.icon(bx, by-2, 'sm_box')
dis.show()
ch = await press.wait()
if ch == 'y':
pp_sofar += here
self.check_length()
return
elif ch == 'x':
if here:
here = here[0:-1]
else:
# quit if they press X on empty screen
return
else:
if len(here) < 32:
here += ch
async def empty_phrase(self, *a):
global pp_sofar
if pp_sofar and len(pp_sofar) >= 3:
if not await ux_confirm("Press OK to clear passphrase. X to cancel."):
return
pp_sofar = ''
await ux_dramatic_pause('Cleared...', 0.25)
async def backspace(self, *a):
global pp_sofar
if pp_sofar:
pp_sofar = pp_sofar[0:-1]
async def view_edit_phrase(self, *a):
# let them control each character
global pp_sofar
pw = await spinner_edit(pp_sofar)
if pw is not None:
pp_sofar = pw
self.check_length()
@classmethod
def check_length(cls):
# enforce a limit of 100 chars
global pp_sofar
pp_sofar = pp_sofar[0:100]
@staticmethod
async def add_text(_1, _2, item):
global pp_sofar
pp_sofar += item.label
PassphraseMenu.check_length()
while not isinstance(the_ux.top_of_stack(), PassphraseMenu):
the_ux.pop()
async def done_cancel(self, *a):
global pp_sofar
if len(pp_sofar) > 3:
if not await ux_confirm("What you have entered will be forgotten."):
return
goto_top_menu()
async def done_apply(self, *a):
# apply the passphrase.
# - important to work on empty string here too.
from stash import bip39_passphrase
old_pw = str(bip39_passphrase)
set_bip39_passphrase(pp_sofar)
xfp = settings.get('xfp')
msg = '''Above is the master key fingerprint of the new wallet.
Press X to abort and keep editing passphrase, OK to use the new wallet, or 1 to use and save to MicroSD'''
ch = await ux_show_story(msg, title="[%s]" % xfp2str(xfp), escape='1')
if ch == 'x':
# go back!
set_bip39_passphrase(old_pw)
return
if ch == '1':
await PassphraseSaver().append(xfp, pp_sofar)
goto_top_menu()
class SingleWordMenu(WordNestMenu):
def __init__(self, items=None, **kws):
if items:
super(SingleWordMenu, self).__init__(items=items, **kws)
else:
super(SingleWordMenu, self).__init__(num_words=1, has_checksum=False, done_cb=None)
@staticmethod
async def all_done(new_words):
# create one more menu w/ the word and some variations on that word
word = new_words[0]
options = [word, word[0].upper() + word[1:], word.upper()]
for w in options[:]:
options.append(' ' + w)
# bugfix: in case they cancel from new menu
WordNestMenu.words = []
return MenuSystem([MenuItem(w, f=PassphraseMenu.add_text)
for n,w in enumerate(options)], space_indicators=True)
def late_draw(self, dis):
#PassphraseMenu.late_draw(self, dis)
pass
async def spinner_edit(pw, confirm_exit=True):
# Allow them to pick each digit using "D-pad"
from glob import dis
from display import FontTiny, FontSmall
# Should allow full unicode, NKDN
# - but limited to what we can show in FontSmall
# - so really just ascii; not even latin-1
# - 8-bit codepoints only
my_rng = range(32, 127) # FontSmall.code_range
symbols = b' !"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'
letters = b'abcdefghijklmnopqrstuvwxyz'
Letters = b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
numbers = b'1234567890'
#assert len(set(symbols+letters+Letters+numbers)) == len(my_rng)
footer1 = "1=Letters 2=Numbers 3=Symbols"
footer2 = "4=SwapCase 0=HELP"
y = 20
pw = bytearray(pw or 'A')
pos = len(pw)-1 # which part being changed
n_visible = const(9)
scroll_x = max(pos - n_visible, 0)
def cycle_set(which, direction=1):
# pick next item in set of choices
for n, s in enumerate(which):
if pw[pos] == s:
try:
pw[pos] = which[n+direction]
except IndexError:
pw[pos] = which[0 if direction==1 else -1]
return
pw[pos] = which[0]
def change(dx):
# next/prev within the same subset of related chars
ch = pw[pos]
for subset in [symbols, letters, Letters, numbers]:
if ch in subset:
return cycle_set(subset, dx)
# probably unreachable code: numeric up/down
ch = pw[pos] + dx
if ch not in my_rng:
ch = (my_rng.stop-1) if dx < 0 else my_rng.start
assert ch in my_rng
pw[pos] = ch
# pre-render the fixed stuff
dis.clear()
dis.text(None, -10, footer1, FontTiny)
dis.text(None, -1, footer2, FontTiny)
dis.save()
# no key-repeat on certain keys
press = PressRelease('4xy')
while 1:
dis.restore()
lr = pos - scroll_x # left/right distance of cursor
if lr < 4 and scroll_x:
scroll_x -= 1
elif lr < 0:
scroll_x = pos
elif lr >= (n_visible-1):
# past right edge
scroll_x += 1
for i in range(n_visible):
# calc abs position in string
ax = scroll_x + i
x = 4 + (13*i)
try:
ch = pw[ax]
except IndexError:
continue
if ax == pos:
# draw cursor
if len(pw) < 2*n_visible:
dis.text(x-4, y-19, '0x%02X' % ch, FontTiny)
dis.icon(x-2, y-10, 'spin')
if ch == 0x20:
dis.icon(x, y+11, 'space')
else:
dis.text(x, y, chr(ch) if ch in my_rng else chr(215), FontSmall)
if scroll_x > 0:
dis.text(2, y-14, str(pw, 'ascii')[0:scroll_x].replace(' ', '_'), FontTiny)
if scroll_x + n_visible < len(pw):
dis.text(-1, 1, "MORE>", FontTiny)
dis.show()
ch = await press.wait()
if ch == 'y':
return str(pw, 'ascii')
elif ch == 'x':
if len(pw) > 1:
# delete current char
pw = pw[0:pos] + pw[pos+1:]
if pos >= len(pw):
pos = len(pw)-1
else:
if confirm_exit:
pp = await ux_show_story(
"OK to leave without any changes? Or X to cancel leaving.")
if pp == 'x': continue
return None
elif ch == '7': # left
pos -= 1
if pos < 0: pos = 0
elif ch == '9': # right
pos += 1
if pos >= len(pw):
if len(pw) < 100 and pw[-3:] != b' ':
pw += ' ' # expand with spaces
else:
pos -= 1 # abort addition
elif ch == '5': # up
change(1)
elif ch == '8': # down
change(-1)
elif ch == '1': # alpha
cycle_set(b'Aa')
elif ch == '4': # toggle case
if (pw[pos] & ~0x20) in range(65, 91):
pw[pos] ^= 0x20
elif ch == '2': # numbers
cycle_set(numbers)
elif ch == '3': # symbols (all of them)
cycle_set(symbols)
elif ch == '0': # help
help_msg = '''\
Use arrow keys (5789) to select letter and move around.
1=Letters (Aa..)
2=Numbers (12..)
3=Symbols (!@#&*)
4=Swap Case (q/Q)
X=Delete char
Add more characters by moving past end (right side).'''
if confirm_exit:
help_msg += '\nTo quit without changes, delete everything.'
await ux_show_story(help_msg)
# EOF