totp

totp is a command-line utility to generate TOTP keys from the command-line. This is very useful for integrating 2-factor authentication support into your existing password-management setup. totp supports both TOTP secret keys and OTP URIs as input. This means you can also integrate totp together with zbarimg to generate TOTP codes from scannable QR codes.

Depdendencies

totp depends on libssl, libcrypto, and liburiparser. You probably already have the first two. If liburiparser isn’t in your systems repositories, you can obtain it from here

Installation

Installation is made easy with the provided Makefile:

$ make
$ make install

Usage

The totp utility reads TOTP secret keys from the standard input and prints the corresponding codes to the standard output. You can use multiple keys:

$ printf '7KFSJ562KJDK23KD\n7YNEG7J3XBIVYR54' | totp
546316
942303

You can also provide the keys as arguments:

$ totp 7KFSJ562KJDK23KD 7YNEG7J3XBIVYR54
546316
942303

By default it is assumed that the TOTP codes have a length of 6 and are valid for 30 seconds. You can change both of these parameters using the -d and -p respectively, if required:

$ totp -d8 -p60 7KFSJ562KJDK23KD 7YNEG7J3XBIVYR54
71696020
18335070

It might be useful however to instead use an OTP URI. These are the URIs embedded within 2-factor authentication QR codes, and often contain the metadata specifying the length and period of the generated codes. To use URIs, use the -u flag:

$ totp -u 'otpauth://totp/GitHub:Mango0x45?secret=7YNEG7J3XBIVYR54'
942303

This also works with the standard input:

$ echo 'otpauth://totp/GitHub:Mango0x45?secret=7YNEG7J3XBIVYR54' | totp -u
942303

Integration with zbarimg

zbarimg is a helpful CLI utility that we can use to get an OTP URI from a QR code. Here is an example of how we can use it to generate a TOTP code from a 2-factor authentication QR code:

$ zbarimg -q qr-code.png | sed 's/QR-Code://' | totp
546316