change password or add user to S/Key
skeyinit initializes the system so you can
use S/Key one-time passwords to log in. The program will ask you to enter a
secret passphrase which is used by
generate one-time passwords: enter a phrase of several words in response.
After the S/Key database has been updated, you can log in using either your
regular password or using S/Key one-time passwords.
skeyinit requires you to type a secret
passphrase, so it should be used only on a secure terminal. For example, on
the console of a workstation or over an encrypted network session. If you
skeyinit while logged in over an untrusted
network, follow the instructions given below with the
Before initializing an S/Key entry, the user must authenticate
using either a standard password or an S/Key challenge. To use a one-time
password for initial authentication,
skey can be used. The user will then be presented with the standard
S/Key challenge and allowed to proceed if it is correct.
skeyinit prints a sequence number and a
one-time password. This password can't be used to log in; one-time passwords
should be generated using skey(1) first. The one-time password printed by
skeyinit can be used to verify if the right
passphrase has been given to skey(1). The one-time password with the corresponding
sequence number printed by skey(1) should match the one printed by
The options are as follows:
- Before an S/Key entry can be initialised, the user must authenticate themselves to the system. This option allows the authentication type to be specified, such as “passwd” or “skey”.
- Disables access to the S/Key database. Only the superuser may use the
- Enables access to the S/Key database. Only the superuser may use the
- Selects the hash algorithm: MD5, RMD-160 (160-bit Ripe Message Digest), or SHA1 (NIST Secure Hash Algorithm Revision 1).
- Start the
skeysequence at count (default is 100).
- Removes the user's S/Key entry.
- Secure mode. The user is expected to have already used a secure machine to
generate the first one-time password. Without the
-soption the system will assume you are directly connected over secure communications and prompt you for your secret passphrase. The
-soption also allows one to set the seed and count for complete control of the parameters.
-soption is specified,
skeyinitwill try to authenticate the user via S/Key, instead of the default listed in /etc/login.conf. If a user has no entry in the S/Key database, an alternate authentication type must be specified via the
-aoption (see above). Entering a password or passphrase in plain text defeats the purpose of using “secure” mode.
You can use
skeyinit -sin combination with the
skeycommand to set the seed and count if you do not like the defaults. To do this run
skeyinit -sin one window and put in your count and seed, then run skey(1) in another window to generate the correct 6 English words for that count and seed. You can then "cut-and-paste" or type the words into the
- Displays one-time passwords in hexadecimal instead of ASCII.
- The username to be changed/added. By default the current user is operated on.
- file containing authentication types
- directory containing user entries for S/Key
$ skeyinit Password: <enter your regular password here> [Updating user with md5] Old seed: [md5] host12377 Enter new secret passphrase: <type a new passphrase here> Again secret passphrase: <again> ID user skey is otp-md5 100 host12378 Next login password: CITE BREW IDLE CAIN ROD DOME $ otp-md5 -n 3 100 host12378 Enter secret passphrase: <type your passphrase here> 98: WERE TUG EDDY GEAR GILL TEE 99: NEAR HA TILT FIN LONG SNOW 100: CITE BREW IDLE CAIN ROD DOME
The one-time password for the next login will have sequence number 99.
- skey disabled
- /etc/skey does not exist or is not accessible by
the user. The superuser may enable
skey(1), skeyaudit(1), skeyinfo(1), skey(5), skeyprune(8)
Neil M. Haller
John S. Walden