This plug-in adds support for OTP time based tokens for pppd PPP server. Compatible with Google Authenticator software token or software/hardware based OTP tokens.
Compile and install otp.so file to your PPP daemon plugins directory and add it to your pppd config:
# use otp passwords
plugin otp.so
The plugin supports following options (default values specified):
# Path to otp secrets file
otp_secrets /etc/ppp/otp-secrets
# Maximum allowed clock slop
otp_slop 180
# T0 value for TOTP (time drift)
totp_t0 0
# Step value for TOTP
totp_step 30
# Number of digits to use from TOTP hash
totp_digits 6
# Step value for MOTP
motp_step 10
The otp-secrets file format is as follows:
# user server type:hash:encoding:key:pin:udid client
# where type is totp, totp-60-6 or motp
# hash should be sha1 in most cases
# encoding is base32, text or text
# key is your key in encoding format
# pin is a 4 digit pin
# udid is used in motp mode
#
# use sha1/base32 for Google Authenticator
bob otp totp:sha1:base32:K7BYLIU5D2V33X6S:1234:xxx *
# use totp-60-6 and sha1/hex for hardware based 60 seconds / 6 digits tokens
mike otp totp-60-6:sha1:hex:5c5a75a87ba1b48cb0b6adfd3b7a5a0e:6543:xxx *
# use text encoding for text based format
jane otp totp:sha1:text:1234567890:9876:xxx *
When users dial in, they will need to provide their username and pin+current OTP number from the OTP token. Example for user bob:
username: bob
password: 1234920151
Originally written by GitHub User kolbyjack This instruction, Base32 and hex support added by Evgeny Gridasov (evgeny.gridasov@gmail.com)