Monkeysphere is a framework to leverage the OpenPGP Web of Trust
(WoT) for key-based authentication. OpenPGP keys are tracked via
GnuPG, and added to the authorized_keys files used by OpenSSH for
monkeysphere-authentication is a Monkeysphere server admin
utility for configuring and managing SSH user authentication through
monkeysphere-authentication takes various subcommands:
Rebuild the monkeysphere-controlled authorized_keys files. For each
specified account, the user ID's listed in the account's
authorized_user_ids file are processed. For each user ID, gpg will be
queried for keys associated with that user ID, optionally querying a
keyserver. If an acceptable key is found (see KEY ACCEPTABILITY in
monkeysphere(7)), the key is added to the account's
monkeysphere-controlled authorized_keys file. If the
RAW_AUTHORIZED_KEYS variable is set, then a separate authorized_keys
file (usually ~USER/.ssh/authorized_keys) is appended to the
monkeysphere-controlled authorized_keys file. If no accounts are
specified, then all accounts on the system are processed. `u' may be
used in place of `update-users'.
Refresh all keys in the monkeysphere-authentication keyring. If no
accounts are specified, then all accounts on the system are processed.
`r' may be used in place of `refresh-keys'.
Output to stdout all acceptable keys for a given user. User IDs are
read from the user's authorized_user_ids file (see
Instruct system to trust user identity certifications made by KEYID.
The key ID will be loaded from the keyserver. A file may be loaded
instead of pulling the key from the keyserver by specifying the path
to the file as the argument, or by specifying `-' to load from stdin.
Using the `-n' or `--domain' option allows you to indicate that you
only trust the given KEYID to make identifications within a specific
domain (e.g. "trust KEYID to certify user identities within the
@example.org domain"). A certifier trust level can be specified with
the `-t' or `--trust' option (possible values are `marginal' and
`full' (default is `full')). A certifier trust depth can be specified
with the `-d' or `--depth' option (default is 1). `c+' may be used in
place of `add-id-certifier'.
Instruct system to ignore user identity certifications made by KEYID.
`c-' may be used in place of `remove-id-certifier'.
List key IDs trusted by the system to certify user identities. `c'
may be used in place of `list-id-certifiers'.
Show the monkeysphere version number. `v' may be used in place of
Output a brief usage summary. `h' or `?' may be used in place of
Setup the server in preparation for Monkeysphere user authentication.
This command is idempotent and run automatically by the other
commands, and should therefore not usually need to be run manually.
`s' may be used in place of `setup'.
Review the state of the server with respect to authentication. `d'
may be used in place of `diagnostics'.
Execute a gpg command, as the monkeysphere user, on the monkeysphere
authentication `sphere' keyring. This takes a single argument
(i.e. multiple gpg arguments need to be quoted all together). Use
this command with caution, as modifying the authentication sphere
keyring can affect ssh user authentication.
SETUP USER AUTHENTICATION
If the server will handle user authentication through
monkeysphere-generated authorized_keys files, the server must be told
which keys will act as identity certifiers. This is done with the
where KEYID is the key ID of the server admin, or whoever's
certifications should be acceptable to the system for the purposes of
authenticating remote users. You can run this command multiple times
to indicate that multiple certifiers are trusted. You may also
specify a filename instead of a key ID, as long as the file contains a
single OpenPGP public key. Certifiers can be removed with the
remove-id-certifier command, and listed with the
A remote user will be granted access to a local account based on the
appropriately-signed and valid keys associated with user IDs listed in
that account's authorized_user_ids file. By default, the
authorized_user_ids file for an account is
~/.monkeysphere/authorized_user_ids. This can be changed in the
The update-users command is used to generate authorized_keys
files for a local account based on the user IDs listed in the
account's authorized_user_ids file:
# monkeysphere-authentication update-users USER
Not specifying USER will cause all accounts on the system to updated.
The ssh server can use these monkeysphere-generated authorized_keys
files to grant access to user accounts for remote users. In order for
sshd to look at the monkeysphere-generated authorized_keys file for
user authentication, the AuthorizedKeysFile parameter must be set in
the sshd_config to point to the monkeysphere-generated
It is recommended to add "monkeysphere-authentication update-users"
to a system crontab, so that user keys are kept up-to-date, and key
revocations and expirations can be processed in a timely manner.
The following environment variables will override those specified in
the config file (defaults in parentheses):
User to control authentication keychain. (monkeysphere)
Set the log level. Can be SILENT, ERROR, INFO, VERBOSE, DEBUG, in
increasing order of verbosity. (INFO)
OpenPGP keyserver to use. (pool.sks-keyservers.net)
Path to user's authorized_user_ids file. %h gets replaced with the
user's homedir, %u with the username.
Path to regular ssh-style authorized_keys file to append to
monkeysphere-generated authorized_keys. `none' means not to add any
raw authorized_keys file. %h gets replaced with the user's homedir,
%u with the username. (%h/.ssh/authorized_keys)
If set to `false', never prompt the user for confirmation. (true)
If set to `false', ignore too-loose permissions on known_hosts,
authorized_keys, and authorized_user_ids files. NOTE: setting this to
false may expose users to abuse by other users on the system. (true)
If monkeysphere-authentication is configured to query an hkps
keyserver, it will use X.509 Certificate Authority certificates in
this file to validate any X.509 certificates used by the keyserver.
If the monkeysphere-authentication-x509 file is present, the
monkeysphere-x509 file will be ignored.
Monkeysphere-generated user authorized_keys files.
A list of OpenPGP user IDs, one per line. OpenPGP keys with an
exactly-matching User ID (calculated valid by the designated identity
certifiers), will have any valid authorization-capable keys or subkeys
added to the given user's authorized_keys file.