ykpamcfg - Manage user settings for the Yubico PAM module

add_hmac_chalresp
       The PAM module can utilize the HMAC-SHA1 Challenge-response (C/R) mode found in YubiKeys starting with
       version 2.2 for offlineauthentication. This action creates the initial state information with the C/R to
       be issued at the next logon.

       The utility currently outputs the state information to a file in the current user’s home directory
       (~/.yubico/challenge-123456 for a YubiKey with serial number API readout enabled, and ~/.yubico/challenge
       for one without).

       The PAM module supports a system-wide directory for these state files (in case the user’s home
       directories are encrypted), but in a system-wide directory, the challenge part should be replaced with
       the username. Example: /var/yubico/challenges/alice-123456

       To use the system-wide mode, you currently have to move the generated state files manually and configure
       the PAM module accordingly.

       Report ykpamcfg bugs in the issue tracker: https://github.com/Yubico/yubico-pam/issues

       First, program a YubiKey for challenge-response on slot 2:

           $ ykpersonalize -2 -ochal-resp -ochal-hmac -ohmac-lt64 -oserial-api-visible
           ...
           Commit? (y/n) [n]: y

       Now, set the current user to require this YubiKey for logon:

           $ ykpamcfg -2 -v
           ...
           Stored initial challenge and expected response in '/home/alice/.yubico/challenge-123456'.

       Then, configure authentication with PAM for example like this (makeabackupfirst):

       /etc/pam.d/common-auth (from Ubuntu 10.10):

           auth  required        pam_unix.so nullok_secure try_first_pass
           auth  [success=1 new_authtok_reqd=ok ignore=ignore default=die] pam_yubico.so mode=challenge-response
           auth  requisite       pam_deny.so
           auth  required        pam_permit.so
           auth  optional        pam_ecryptfs.so unwrap

       ykpamcfg - Manage user settings for the Yubico PAM module

-1
           Use slot 1. This is the default.

       -2
           Use slot 2.

       -Aaction
           Choose action to perform. See ACTIONS below.

       -ppath
           Specify output file, default is ~/.yubico/challenge.-iiterations
           Number of iterations to use for PBKDF2 of expected response.

       -v
           Enable verbose mode.

       -V
           Display version and exit.

       -h
           Display help and exit.

pam_yubico(8)

       The yubico-pam home page: https://developers.yubico.com/yubico-pam/

       YubiKeys can be obtained from Yubico: http://www.yubico.com/

yubico-pam                                        Version 2.27                                       YKPAMCFG(1)

ykpamcfg [-1 | -2] [-A] [-p] [-i] [-v] [-V] [-h]