Time-based OTPs

import rlotp
import time

totp = rlotp.TOTP('base32secret3232')
totp.now() # => '492039'

# OTP verified for current time
totp.verify('492039') # => True
time.sleep(30)
totp.verify('492039') # => False

Counter-based OTPs

import rlotp

hotp = rlotp.HOTP('base32secret3232')
hotp.at(0) # => '260182'
hotp.at(1) # => '055283'
hotp.at(1401) # => '316439'

# OTP verified with a counter
hotp.verify('316439', 1401) # => True
hotp.verify('316439', 1402) # => False

Generating a Secret Key

A helper function is provided to generate a 32-character base32 secret, compatible with Google Authenticator and other OTP apps:

rlotp.random_base32()

Some applications want the secret key to be formatted as a hex-encoded string:

rlotp.random_hex()  # returns a 40-character hex-encoded secret

Google Authenticator Compatible

RLOTP works with the Google Authenticator iPhone and Android app, as well as other OTP apps like Authy. RLOTP includes the ability to generate provisioning URIs for use with the QR Code scanner built into these MFA client apps:

rlotp.totp.TOTP('JBSWY3DPEHPK3PXP').provisioning_uri(name='alice@google.com', issuer_name='Secure App')

>>> 'otpauth://totp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App'

rlotp.hotp.HOTP('JBSWY3DPEHPK3PXP').provisioning_uri(name="alice@google.com", issuer_name="Secure App", initial_count=0)

>>> 'otpauth://hotp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App&counter=0'

This URL can then be rendered as a QR Code (for example, using https://github.com/soldair/node-qrcode) which can then be scanned and added to the users list of OTP credentials.

Parsing these URLs is also supported:

rlotp.parse_uri('otpauth://totp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App')

>>> <rlotp.totp.TOTP object at 0xFFFFFFFF>

rlotp.parse_uri('otpauth://hotp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App&counter=0'

>>> <rlotp.totp.HOTP object at 0xFFFFFFFF>

Working example

Scan the following barcode with your phone’s OTP app (e.g. Google Authenticator):

Now run the following and compare the output:

import rlotp
totp = rlotp.TOTP("JBSWY3DPEHPK3PXP")
print("Current OTP:", totp.now())

Third-party contributions

The following third-party contributions are not described by a standard, not officially supported, and provided for reference only:

• rlotp.contrib.Steam(): An implementation of Steam TOTP. Uses the same API as rlotp.TOTP().

Links

• Project home page (GitHub)

• Documentation

• Package distribution (PyPI)

• Change log

• RFC 4226: HOTP: An HMAC-Based One-Time Password

• RFC 6238: TOTP: Time-Based One-Time Password Algorithm

• ROTP - Original Ruby OTP library by Mark Percival

• OTPHP - PHP port of ROTP by Le Lag

• OWASP Authentication Cheat Sheet

• NIST SP 800-63-3: Digital Authentication Guideline

For new applications:

• WebAuthn

• PyWARP

Versioning

This package follows the Semantic Versioning 2.0.0 standard. To control changes, it is recommended that application developers pin the package version and manage it using pip-tools or similar. For library developers, pinning the major version is recommended.