NAME¶

genotpurl — Generate Google Authenticator URLs

SYNOPSIS¶

DESCRIPTION¶

genotpurl is a utility for generating URLs for the Google Authenticator cell phone app, which generates one-time passwords compatible with the HOTP/OATH algorithm defined by RFC 4226. When such and URL is clicked on a cell phone, the token is automatically installed into the Google Authenticator app. This is a convenient way to deploy such tokens.

The issuer and label are required; these strings are displayed in the app along with the current token value.

The key is the token's binary secret key and is specified as a hexadecimal string. If no key is given, genotpurl generates a random key and prints it to standard output.

The -i, -c, -d, and -p flags allow creation of non-standard tokens, but these may not be supported by Google Authenticator.

OPTIONS¶

-c

Specify the starting target counter value for the one-time password generation. This flag is incompatible with the -t flag.

-d

Specify the number of digits in the one-time password. The default value is six.

-h

Print the usage message and exit successfully.

-I

Specify token issuer (e.g., "Example Industries, Inc.")

-i

Create an interval-based token instead of a time-based token.

-k

Specify the token binary secret key as a hexadecimal string.

If no key is given, genotpurl generates a random key and prints it to standard output.

-K

Specify generated key length. Ignored if -k is also specified.

-L

Specify token label (e.g., "user@example.com")

-p

Specify the length of a single time interval in seconds. The default value is 30 seconds. Ignored if -i is given.

SEE ALSO¶

mod_authn_otp: Apache module for one-time password authentication, https://github.com/archiecobbs/mod-authn-otp.

Google Authenticator (iOS), https://itunes.apple.com/us/app/google-authenticator/id388497605?mt=8.

Google Authenticator (Android), https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2&hl=en_US.

AUTHOR¶

Archie L. Cobbs ⟨archie@dellroad.org⟩