PyOTP - The Python One-Time Password Library
PyOTP is a Python library for generating and verifying one-time passwords. It can be used to implement two-factor (2FA) or multi-factor (MFA) authentication methods in web applications and in other systems that require users to log in.
Open MFA standards are defined in RFC 4226 (HOTP: An HMAC-Based One-Time Password Algorithm) and in RFC 6238 (TOTP: Time-Based One-Time Password Algorithm). PyOTP implements server-side support for both of these standards. Client-side support can be enabled by sending authentication codes to users over SMS or email (HOTP) or, for TOTP, by instructing users to use Google Authenticator, Authy, or another compatible app. Users can set up auth tokens in their apps easily by using their phone camera to scan otpauth:// QR codes provided by PyOTP.
We recommend that implementers read the OWASP Authentication Cheat Sheet and NIST SP 800-63-3: Digital Authentication Guideline for a high level overview of authentication best practices.
Quick overview of using One Time Passwords on your phone
- OTPs involve a shared secret, stored both on the phone and the server
- OTPs can be generated on a phone without internet connectivity
- OTPs should always be used as a second factor of authentication (if your phone is lost, you account is still secured with a password)
- Google Authenticator and other OTP client apps allow you to store multiple OTP secrets and provision those using a QR Code
pip install pyotp
totp = pyotp.TOTP('base32secret3232') totp.now() # => '492039' # OTP verified for current time totp.verify('492039') # => True time.sleep(30) totp.verify('492039') # => False
hotp = pyotp.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 base32 Secret Key
pyotp.random_base32() # returns a 16 character base32 secret. Compatible with Google Authenticator and other OTP apps
Google Authenticator Compatible
PyOTP works with the Google Authenticator iPhone and Android app, as well as other OTP apps like Authy. PyOTP includes the ability to generate provisioning URIs for use with the QR Code scanner built into these MFA client apps:
pyotp.totp.TOTP('JBSWY3DPEHPK3PXP').provisioning_uri("email@example.com", issuer_name="Secure App") >>> 'otpauth://totp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App' pyotp.hotp.HOTP('JBSWY3DPEHPK3PXP').provisioning_uri("firstname.lastname@example.org", initial_count=0, issuer_name="Secure App") >>> '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/neocotic/qrious) which can then be scanned and added to the users list of OTP credentials.
Scan the following barcode with your phone's OTP app (e.g. Google Authenticator):
Now run the following and compare the output:
import pyotp totp = pyotp.TOTP("JBSWY3DPEHPK3PXP") print("Current OTP:", totp.now())
- Project home page (GitHub)
- Documentation (Read the Docs)
- 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