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.
Implementers should read and follow the HOTP security requirements and TOTP security considerations sections of the relevant RFCs. At minimum, application implementers should follow this checklist:
We also 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 phonepip install pyotp
import pyotp import time totp = pyotp.TOTP('base32secret3232') totp.now() # => '492039' # OTP verified for current time totp.verify('492039') # => True time.sleep(30) totp.verify('492039') # => False
import pyotp 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
A helper function is provided to generate a 32-character base32 secret, compatible with Google Authenticator and other OTP apps:
pyotp.random_base32()
Some applications want the secret key to be formatted as a hex-encoded string:
pyotp.random_hex() # returns a 40-character hex-encoded secretGoogle 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(name='alice@google.com', issuer_name='Secure App') >>> 'otpauth://totp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App' pyotp.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:
pyotp.parse_uri('otpauth://totp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App') >>> <pyotp.totp.TOTP object at 0xFFFFFFFF> pyotp.parse_uri('otpauth://hotp/Secure%20App:alice%40google.com?secret=JBSWY3DPEHPK3PXP&issuer=Secure%20App&counter=0' >>> <pyotp.totp.HOTP object at 0xFFFFFFFF>
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())Third-party contributions
The following third-party contributions are not described by a standard, not officially supported, and provided for reference only:
pyotp.contrib.Steam()
: An implementation of Steam TOTP. Uses the same API as pyotp.TOTP().For new applications:
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.
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