mmgen-wallet/mmgen/common.py

#!/usr/bin/env python3
#
# mmgen = Multi-Mode GENerator, command-line Bitcoin cold storage solution
# Copyright (C)2013-2020 The MMGen Project <mmgen@tuta.io>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
common.py:  Common imports for all MMGen scripts
"""

import sys,os
from .exception import *
from .globalvars import *
import mmgen.opts as opts
from .opts import opt
from .util import *

def help_notes(k):
	from .obj import SubSeedIdxRange,SeedShareIdx,SeedShareCount,MasterShareIdx
	from .wallet import Wallet
	from .tx import MMGenTX
	def fee_spec_letters(use_quotes=False):
		cu = g.proto.coin_amt.units
		sep,conj = ((',',' or '),("','","' or '"))[use_quotes]
		return sep.join(u[0] for u in cu[:-1]) + ('',conj)[len(cu)>1] + cu[-1][0]
	def fee_spec_names():
		cu = g.proto.coin_amt.units
		return ', '.join(cu[:-1]) + ('',' and ')[len(cu)>1] + cu[-1] + ('',',\nrespectively')[len(cu)>1]
	return {
		'rel_fee_desc': MMGenTX().rel_fee_desc,
		'fee_spec_letters': fee_spec_letters(),
		'seedsplit': """
COMMAND NOTES:

This command generates shares one at a time.  Shares may be output to any
MMGen wallet format, with one limitation: only one share in a given split may
be in hidden incognito format, and it must be the master share in the case of
a master-share split.

If the command's optional first argument is omitted, the default wallet is
used for the split.

The last argument is a seed split specifier consisting of an optional split
ID, a share index, and a share count, all separated by colons.  The split ID
must be a valid UTF-8 string.  If omitted, the ID 'default' is used.  The
share index (the index of the share being generated) must be in the range
{sia}-{sib} and the share count (the total number of shares in the split)
in the range {sca}-{scb}.

Master Shares

Each seed has a total of {msb} master shares, which can be used as the first
shares in multiple splits if desired.  To generate a master share, use the
--master-share (-M) option with an index in the range {msa}-{msb} and omit
the last argument.

When creating and joining a split using a master share, ensure that the same
master share index is used in all split and join commands.

EXAMPLES:

  Split a BIP39 seed phrase into two BIP39 shares.  Rejoin the split:

    $ echo 'zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong' > sample.bip39

    $ mmgen-seedsplit -o bip39 sample.bip39 1:2
    BIP39 mnemonic data written to file '03BAE887-default-1of2[D51CB683][128].bip39'

    $ mmgen-seedsplit -o bip39 sample.bip39 2:2
    BIP39 mnemonic data written to file '03BAE887-default-2of2[67BFD36E][128].bip39'

    $ mmgen-seedjoin -o bip39 \\
        '03BAE887-default-2of2[67BFD36E][128].bip39' \\
        '03BAE887-default-1of2[D51CB683][128].bip39'
    BIP39 mnemonic data written to file '03BAE887[128].bip39'

    $ cat '03BAE887[128].bip39'
    zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong

  Create a 3-way default split of your default wallet, outputting all shares
  to default wallet format.  Rejoin the split:

    $ mmgen-seedsplit 1:3 # Step A
    $ mmgen-seedsplit 2:3 # Step B
    $ mmgen-seedsplit 3:3 # Step C
    $ mmgen-seedjoin <output_of_step_A> <output_of_step_B> <output_of_step_C>

  Create a 2-way split of your default wallet with ID string 'alice',
  outputting shares to MMGen native mnemonic format.  Rejoin the split:

    $ mmgen-seedsplit -o words alice:1:2 # Step D
    $ mmgen-seedsplit -o words alice:2:2 # Step E
    $ mmgen-seedjoin <output_of_step_D> <output_of_step_E>

  Create a 2-way split of your default wallet with ID string 'bob' using
  master share #7, outputting share #1 (the master share) to default wallet
  format and share #2 to BIP39 format.  Rejoin the split:

    $ mmgen-seedsplit -M7                   # Step X
    $ mmgen-seedsplit -M7 -o bip39 bob:2:2  # Step Y
    $ mmgen-seedjoin -M7 --id-str=bob <output_of_step_X> <output_of_step_Y>

  Create a 2-way split of your default wallet with ID string 'alice' using
  master share #7.  Rejoin the split using master share #7 generated in the
  previous example:

    $ mmgen-seedsplit -M7 -o bip39 alice:2:2 # Step Z
    $ mmgen-seedjoin -M7 --id-str=alice <output_of_step_X> <output_of_step_Z>

  Create a 2-way default split of your default wallet with an incognito-format
  master share hidden in file 'my.hincog' at offset 1325.  Rejoin the split:

    $ mmgen-seedsplit -M4 -o hincog -J my.hincog,1325 1:2 # Step M (share A)
    $ mmgen-seedsplit -M4 -o bip39 2:2                    # Step N (share B)
    $ mmgen-seedjoin -M4 -H my.hincog,1325 <output_of_step_N>

""".strip().format(
	sia=SeedShareIdx.min_val,sib=SeedShareIdx.max_val,
	sca=SeedShareCount.min_val,scb=SeedShareCount.max_val,
	msa=MasterShareIdx.min_val,msb=MasterShareIdx.max_val),
		'subwallet': """
SUBWALLETS:

Subwallets (subseeds) are specified by a "Subseed Index" consisting of:

  a) an integer in the range 1-{}, plus
  b) an optional single letter, 'L' or 'S'

The letter designates the length of the subseed.  If omitted, 'L' is assumed.

Long ('L') subseeds are the same length as their parent wallet's seed
(typically 256 bits), while short ('S') subseeds are always 128-bit.
The long and short subseeds for a given index are derived independently,
so both may be used.

MMGen has no notion of "depth", and to an outside observer subwallets are
identical to ordinary wallets.  This is a feature rather than a bug, as it
denies an attacker any way of knowing whether a given wallet has a parent.

Since subwallets are just wallets, they may be used to generate other
subwallets, leading to hierarchies of arbitrary depth.  However, this is
inadvisable in practice for two reasons:  Firstly, it creates accounting
complexity, requiring the user to independently keep track of a derivation
tree.  More importantly, however, it leads to the danger of Seed ID
collisions between subseeds at different levels of the hierarchy, as
MMGen checks and avoids ID collisions only among sibling subseeds.

An exception to this caveat would be a multi-user setup where sibling
subwallets are distributed to different users as their default wallets.
Since the subseeds derived from these subwallets are private to each user,
Seed ID collisions among them doesn't present a problem.

A safe rule of thumb, therefore, is for *each user* to derive all of his/her
subwallets from a single parent.  This leaves each user with a total of two
million subwallets, which should be enough for most practical purposes.
""".strip().format(SubSeedIdxRange.max_idx),
		'passwd': """
PASSPHRASE NOTE:

For passphrases all combinations of whitespace are equal, and leading and
trailing space are ignored.  This permits reading passphrase or brainwallet
data from a multi-line file with free spacing and indentation.
""".strip(),
		'brainwallet': """
BRAINWALLET NOTE:

To thwart dictionary attacks, it's recommended to use a strong hash preset
with brainwallets.  For a brainwallet passphrase to generate the correct
seed, the same seed length and hash preset parameters must always be used.
""".strip(),
		'txcreate': """
The transaction's outputs are specified on the command line, while its inputs
are chosen from a list of the user's unspent outputs via an interactive menu.

If the transaction fee is not specified on the command line (see FEE
SPECIFICATION below), it will be calculated dynamically using network fee
estimation for the default (or user-specified) number of confirmations.
If network fee estimation fails, the user will be prompted for a fee.

Network-estimated fees will be multiplied by the value of '--tx-fee-adj',
if specified.

Ages of transactions are approximate based on an average block discovery
interval of one per {g.proto.secs_per_block} seconds.

All addresses on the command line can be either {pnu} addresses or {pnm}
addresses of the form <seed ID>:<index>.

To send the value of all inputs (minus TX fee) to a single output, specify
one address with no amount on the command line.
""".format(g=g,pnm=g.proj_name,pnu=g.proto.name),
		'fee': """
FEE SPECIFICATION: Transaction fees, both on the command line and at the
interactive prompt, may be specified as either absolute {c} amounts, using
a plain decimal number, or as {r}, using an integer followed by
'{l}', for {u}.
""".format( c=g.coin,
			r=MMGenTX().rel_fee_desc,
			l=fee_spec_letters(use_quotes=True),
			u=fee_spec_names() ),
		'txsign': """
Transactions may contain both {pnm} or non-{pnm} input addresses.

To sign non-{pnm} inputs, a {dn} wallet dump or flat key list is used
as the key source ('--keys-from-file' option).

To sign {pnm} inputs, key data is generated from a seed as with the
{pnl}-addrgen and {pnl}-keygen commands.  Alternatively, a key-address file
may be used (--mmgen-keys-from-file option).

Multiple wallets or other seed files can be listed on the command line in
any order.  If the seeds required to sign the transaction's inputs are not
found in these files (or in the default wallet), the user will be prompted
for seed data interactively.

To prevent an attacker from crafting transactions with bogus {pnm}-to-{pnu}
address mappings, all outputs to {pnm} addresses are verified with a seed
source.  Therefore, seed files or a key-address file for all {pnm} outputs
must also be supplied on the command line if the data can't be found in the
default wallet.
""".format( dn=g.proto.daemon_name,
			pnm=g.proj_name,
			pnu=g.proto.name,
			pnl=g.proj_name.lower())
	}[k] + ('-α' if g.debug_utf8 else '')

def exit_if_mswin(feature):
	if g.platform == 'win':
		m = capfirst(feature) + ' not supported on the MSWin / MSYS2 platform'
		ydie(1,m)