Provided by: monkeysphere_0.22-1_i386
monkeysphere-server - Monkeysphere server admin user interface
monkeysphere-server subcommand [args]
Monkeysphere is a framework to leverage the OpenPGP web of trust for
OpenSSH authentication. OpenPGP keys are tracked via GnuPG, and added
to the authorized_keys and known_hosts files used by OpenSSH for
monkeysphere-server is the Monkeysphere server admin utility.
monkeysphere-server 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’.
Generate a OpenPGP key for the host. If HOSTNAME is not
specified, then the system fully-qualified domain name will be
user. An alternate key bit length can be specified with the
‘-l’ or ‘--length’ option (default 2048). An expiration length
can be specified with the ‘-e’ or ‘--expire’ option (prompt
otherwise). The expiration format is the same as that of
extend-key, below. A key revoker fingerprint can be specified
with the ‘-r’ or ‘--revoker’ option. ‘g’ may be used in place
Extend the validity of the OpenPGP key for the host until EXPIRE
from the present. If EXPIRE is not specified, then the user
will be prompted for the extension term. Expiration is
specified like GnuPG does:
0 = key does not expire
<n> = key expires in n days
<n>w = key expires in n weeks
<n>m = key expires in n months
<n>y = key expires in n years
‘e’ may be used in place of ‘extend-key’.
Add a hostname user ID to the server host key. ‘n+’ may be used
in place of ‘add-hostname’.
Revoke a hostname user ID from the server host key. ‘n-’ may be
used in place of ‘revoke-hostname’.
Output gpg information about host’s OpenPGP key. ‘s’ may be
used in place of ‘show-key’.
Publish the host’s OpenPGP key to the keyserver. ‘p’ may be
used in place of ‘publish-key’.
Review the state of the server with respect to the MonkeySphere
in general and report on suggested changes. Among other checks,
this includes making sure there is a valid host key, that the
key is published, that the sshd configuration points to the
right place, and that there are at least some valid identity
certifiers. ‘d’ may be used in place of ‘diagnostics’.
Instruct system to trust user identity certifications made by
KEYID. 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-identity-certifier’.
Instruct system to ignore user identity certifications made by
KEYID. ‘c-’ may be used in place of ‘remove-identity-
List key IDs trusted by the system to certify user identities.
‘c’ may be used in place of ‘list-identity-certifiers’.
Execute a gpg command on the gnupg-authentication keyring as the
monkeysphere user. This takes a single command (multiple gpg
arguments need to be quoted). Use this command with caution, as
modifying the gnupg-authentication keyring can affect ssh user
help Output a brief usage summary. ‘h’ or ‘?’ may be used in place
In order to start using the monkeysphere, you must first generate an
OpenPGP key for the server and convert that key to an ssh key that can
be used by ssh for host authentication. This can be done with the gen-
$ monkeysphere-server gen-key
To enable host verification via the monkeysphere, you must then publish
the host’s key to the Web of Trust using the publish-key command to
push the key to a keyserver. You must also modify the sshd_config on
the server to tell sshd where the new server host key is located:
In order for users logging into the system to be able to identify the
host via the monkeysphere, at least one person (e.g. a server admin)
will need to sign the host’s key. This is done using standard OpenPGP
keysigning techniques, usually: pul the key from the keyserver, verify
and sign the key, and then re-publish the signature. Once an admin’s
signature is published, users logging into the host can use it to
validate the host’s key.
If the server will also 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 add-
$ monkeysphere-server add-identity-certifier KEYID
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-
identity-certifier command, and listed with the list-identity-
Remote users will then 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 can then be used to generate authorized_keys
file for local accounts based on the authorized user IDs listed in the
account’s authorized_user_ids file:
$ monkeysphere-server update-users USER
Not specifying USER will cause all accounts on the system to updated.
sshd can then use these monkeysphere generated authorized_keys files to
grant access to user accounts for remote users. You must also tell
sshd to look at the monkeysphere-generated authorized_keys file for
user authentication by setting the following in the sshd_config:
It is recommended to add "monkeysphere-server 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 monkeysphere-server.conf configuration file (defaults in
User to control authentication keychain (monkeysphere).
Set the log level (INFO). Can be SILENT, ERROR, INFO, VERBOSE,
DEBUG, in increasing order of verbosity.
OpenPGP keyserver to use (subkeys.pgp.net).
Path to user authorized_user_ids file
Path to user-controlled authorized_keys file. ‘-’ means not to
add user-controlled file (%h/.ssh/authorized_keys).
System monkeysphere-server config file.
System-wide monkeysphere config file.
Monkeysphere host GNUPG home gpg.conf
Monkeysphere authentication GNUPG home gpg.conf
Monkeysphere-generated user authorized_keys files.
Copy of the host’s private key in ssh format, suitable for use
Monkeysphere host GNUPG home directory.
Monkeysphere authentication GNUPG home directory.
Written by Jameson Rollins <email@example.com>, Daniel Kahn
monkeysphere(1), monkeysphere(7), gpg(1), ssh(1)