Passphrases to remember
Passphrases to remember...
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dicewareis a passphrase generator following the proposals of Arnold G. Reinhold on http://diceware.com . It generates passphrases by concatenating words randomly picked from wordlists. For instance::
$ diceware MyraPend93rdSixthEagleAid
The passphrase contains by default six words (with first char capitalized) without any separator chars. Optionally you can let
dicewareinsert special chars into the passphrase.
dicewaresupports several sources of randomness (including real life dice) and different wordlists (including cryptographically signed ones).
This Python package can be installed via pip_::
$ pip install diceware
The exact way depends on your operating system.
Once installed, use
--helpto list all available options::
$ diceware --help Create a passphrase
positional arguments: INFILE Input wordlist. `-' will read from stdin.
optional arguments: -h, --help show this help message and exit -n NUM, --num NUM number of words to concatenate. Default: 6 -c, --caps Capitalize words. This is the default. --no-caps Turn off capitalization. -s NUM, --specials NUM Insert NUM special chars into generated word. -d DELIMITER, --delimiter DELIMITER Separate words by DELIMITER. Empty string by default. -r SOURCE, --randomsource SOURCE Get randomness from this source. Possible values:
realdice',system'. Default: system -w NAME, --wordlist NAME Use words from this wordlist. Possible values:
en',eneff', `enorig', `ensecuredrop'. Wordlists are stored in the folder displayed below. Default: eneff -v, --verbose Be verbose. Use several times for increased verbosity. --version output version information and exit.
Arguments related to `realdice' randomsource: --dice-sides N Number of sides of dice. Default: 6
Wordlists are stored in
-nyou can tell how many words are supposed to be picked for your new passphrase::
$ diceware -n 1 Thud
$ diceware -n 2 KnitMargo
dicewareadditionally let generate special chars to replace characters in the 'normal' passphrase. The number of special chars generated can be determined with the
-soption (default is zero)::
$ diceware -s 2 Heroic%unkLon#DmLewJohns
"#"are the special chars.
Special chars are taken from the following list::
Please note that several special chars might replace the same original char, resulting in a passphrase with less special chars than requested.
-dyou can advise
dicewareto put a delimiter string between the words generated::
$ diceware -d "" WavyBaden400WhelpQuestMacon
By default we use the empty string as delimiter, which is good for copying via double click on Linux systems. But other delimiters might make your passphrases more readable (and more secure, see
Security Traps_ below).
By default the single phrase words are capitalized, i.e. the first char of each word is made uppercase. This does not necessarily give better entropy (but protects against entropy loss due to non
prefix code, see
Security Trapsbelow), and it might improve phrase readability.
You can nevertheless disable caps with the
$ diceware --no-caps oceanblendbaronferrylistenvalet
This will leave the input words untouched (upper-case stays upper-case, lower-case stays lower-case). It does not mean, that all output words will be lower-case (except if all words of your wordlist are lowercase).
As the default lists of
dicewarecontain only lower-case terms, here
--no-capsmeans in fact lower-case only output, which might be easier to type on smart phones and similar.
dicewaresupports also different sources of randomness, which can be chosen with the
--randomsourceoption. Use the
--helpoption to list all valid values for this option.
By default we use the
random.SystemRandom_ class of standard Python lib but you can also bring your own dice to create randomness::
$ diceware -r realdice --dice-sides 6 Please roll 5 dice (or a single dice 5 times). Enter your 5 dice results, separated by spaces: 6 4 2 3 1 Please roll 5 dice (or a single dice 5 times). Enter your 5 dice results, separated by spaces: 5 4 3 6 2 ... UnleveledSimilarlyBackboardMurkyOasisReplay
Normally dice have six sides. And this is also the default in
dicewareif you do not use
--dice-sides. But if you do, you can tell how many sides (all) your dice have. More sides will lead to less rolls required.
We support even sources of randomness from other packages. See the
documentation_ for more details.
dicewarecomes with an English wordlist provided by the EFF, which will be used by default and contains 7776 (=6^5) different words. This list is registered as ``eneff``.
dicewarecomes with an English wordlist provided by
@heartsucker_, which contains 8192 different words. This list is based off the original diceware list written by Arnold G. Reinhold.
Both the original and 8k diceware wordlists by Mr. Reinhold are provided. You can enable a certain (installed) wordlist with the
$ diceware --wordlist en_orig YorkNodePrickEchoToriNiobe
diceware --helpfor a list of all installed wordlists.
If you do not like the wordlists provided, you can use your own one. Any
INFILEprovided will be parsed line by line and each line considered a possible word. For instance::
$ echo -e "hi\nhello\n" > mywordlist.txt $ diceware mywordlist.txt HelloHelloHiHiHiHello
With dash (
-) as filename you can pipe in wordlists::
$ echo -e "hi\nhello\n" | diceware - HiHiHelloHiHiHello
In custom wordlists we take each line for a valid word and ignore empty lines (i.e. lines containing whitespace characters only). Oh, and we handle even PGP-signed wordlists.
You can set customized default values in a configuration file
.diceware.ini(note the leading dot) placed in your home directory. This file could look like this::
[diceware] num = 7 caps = off specials = 2 delimiter = "MYDELIMITER" randomsource = "system" wordlist = "en_securedrop"
The options names have to match long argument names, as output by
--help. The values set must meet the requirements valid for commandline usage. All options must be set within a section
dicewarepassphrases are easier to remember than shorter passwords constructed in more or less bizarre ways. But at the same time
dicewarepassphrases provide more entropy as
xkcd_ can show with the famous '936' proof_:
.. image:: http://imgs.xkcd.com/comics/password_strength.png :align: center :target: http://xkcd.com/936/
.. _xkcd: http://xkcd.com/ .. _proof: http://xkcd.com/936/
The standard english wordlist of this
dicewareimplementation contains 7776 = 6^5 different english words. It is the official EFF_ wordlist. compiled by
Joseph Bonneau_. Therefore, picking a random word from this list gives an entropy of nearly 12.9 bits. Picking six words means an entropy of 6 x 12.9 = 77.54 bits.
The special chars replacing chars of the originally created passphrase give some more entropy (the more chars you have, the more additional entropy), but not much. For instance, for a sixteen chars phrase you have sixteen possibilities to place one of the 36 special chars. That makes 36 x 16 possibilitities or an entropy of about 9.17 you can add. To get an entropy increase of at least 10 bits, you have to put a special char in a phrase with at least 29 chars (while at the same time an additional word would give you 13 bits of extra entropy). Therefore you might think again about using special chars in your passphrase.
The security level provided by Diceware_ depends heavily on your source of random. If the delivered randomness is good, then your passphrases will be very strong. If instead someone can foresee the numbers generated by a random number generator, your passphrases will be surprisingly weak.
This Python implementation uses (by default) the
random.SystemRandom_ source provided by Python. On Un*x systems it accesses
/dev/urandom. You might want to follow reports about manipulated random number generators in operating systems closely.
The Python API of this package allows usage of other sources of randomness when generating passphrases. This includes real dice. See the
There are issues that might reduce the entropy of the passphrase generated. One of them is the
prefix code_ problem:
Prefix Code ...........
If the wordlist contains, for example, the words::
"air", "airport", "portable", "able"
and we switched off caps and delimiter chars, then
dicewaremight generate a passphrase containing::
which could come from
airport-able. We cannot tell and an attacker would have less combinations to guess.
To avoid that, you can leave caps enabled (the default), use any word delimiter except the empty string or use the
en_effwordlist, which was checked to be a
prefix code_ (i.e. it does not contain words that start with other words in the list). The
pt-bris also a secure
Each of these measures is sufficient to protect you against the
prefix code_ problem.
Reduced Entropy ...............
dicewareis a kind of mapping input values, dice throws for instance, onto wordlist entries. We normally want each of the words in the wordlist to be picked for passphrases with the same probability.
This, however, is not possible, if the number of wordlist entries is not a power of dice sides. In that case we cut some words of the wordlist and inform the user about the matter. Reducing the number of words this way makes it easier for attackers to guess the phrase picked.
You can fix that problem by using longer wordlists.
Developers want to
fork me on github_::
$ git clone https://github.com/ulif/diceware.git
We recommend to create and activate a virtualenv_ first::
$ cd diceware/ $ virtualenv -p /usr/bin/python3.4 py34 $ source py34/bin/activate (py34) $
We support Python versions 2.6, 2.7, 3.3 to 3.7, and pypy.
Now you can create the devel environment::
(py34) $ python setup.py dev
This will fetch test packages (py.test_). You should be able to run tests now::
(py34) $ py.test
If you have also different Python versions installed you can use tox_ for using them all for testing::
(py34) $ pip install tox # only once (py34) $ tox
Should run tests in all supported Python versions.
Documentation Install .....................
The docs can be generated with Sphinx_. The needed packages are installed via::
(py34) $ python setup.py docs
To create HTML you have to go to the
docs/directory and use the prepared
(py34) $ cd docs/ (py34) $ make
This should generate the docs in
Creating the Man Page .....................
We provide a
ReStructuredTexT_ template to create a man page. When the documentation engine is installed (
Sphinx_, see above), then you can create a manpage doing::
(py34) $ rst2man.py docs/manpage.rst > diceware.1
The template is mainly provided to ease the job of Debian maintainers. Currently, it is not automatically updated. Dates, authors, synopsis, etc. have to be updated manually. Information in the manpage may therefore be wrong, outdated, or simply misleading.
Arnold G. Reinhold deserves all merits for the working parts of
Diceware_. The non-working parts are certainly my fault.
People that helped spotting bugs, providing solutions, etc.:
Conor Schaefer (conorsch)_
@drebs_ provided patches and discussion for different sources of randomness and the excellent
@drebs_ also initiated and performed the packaging of
Debian_ platform. Many kudos for this work!
@drebs_ is also the official Debian maintainer of the
@heartsucker_ hand-compiled and added a new english wordlist.
dwcoder_ revealed and fixed bugs #19, #21, #23. Also showed sound knowledge of (theoretical) entropy. A pleasure to work with.
George V. Reilly_ pointed to new EFF wordlists.
lieryan_ brought up the
prefix code_ problem.
LogosOfJ_ discovered and fixed serious
realdicesource of randomness problem.
Bhavin Gandhi_ fixed the confusing error message when an invalid input filename is given.
Simon Fondrie-Teitler_ contributed a machine-readable copyright file, with improvements from
Doug Muth_ fixed formatting in docs.
Many thanks to all of them!
fork me on github_
Diceware standard list_ by Arnold G. Reinhold.
Diceware8k list_ by Arnold G. Reinhold.
Diceware SecureDrop list_ by
EFF large list_ provided by EFF_.
This Python implementation of Diceware, (C) 2015-2019 Uli Fouquet, is licensed under the GPL v3+. See file LICENSE for details.
"Diceware" is a trademark of Arnold G Reinhold, used with permission.
The copyright for the
Diceware8k list_ is owned by Arnold G Reinhold. The copyright for the the
Diceware SecureDrop list_ are owned by
@heartsucker. Copyright for the
EFF large listby
Joseph Bonneau_ and EFF_. See file COPYRIGHT for details.
.. pip: https://pip.pypa.io/en/latest/ .. _
@anarcat: https://github.com/anarcat .. _
Debian: https://www.debian.org/ .. _
Diceware: http://diceware.com/ .. _
Diceware standard list: http://world.std.com/~reinhold/diceware.wordlist.asc .. _
Diceware SecureDrop list: https://github.com/heartsucker/diceware .. _
Diceware8k list: http://world.std.com/~reinhold/diceware8k.txt .. _
@drebs: https://github.com/drebs .. _
EFF: https://eff.org/ .. _
EFF large list: https://www.eff.org/files/2016/07/18/efflargewordlist.txt .. _
fork me on github: http://github.com/ulif/diceware/ .. _
@heartsucker: https://github.com/heartsucker/ .. _
Joseph Bonneau: https://www.eff.org/about/staff/joseph-bonneau .. _
prefix code: https://en.wikipedia.org/wiki/Prefixcode .. _
random.SystemRandom: https://docs.python.org/3.4/library/random.html#random.SystemRandom .. _ReStructuredText: http://docutils.sourceforge.net/rst.html .. _virtualenv: https://virtualenv.pypa.io/ .. _py.test: https://pytest.org/ .. _tox: https://tox.testrun.org/ .. _Sphinx: https://sphinx-doc.org/