OTPpy

OTP library for Python 3 : HOTP and TOTP ( RFC4226 & RFC6238 )

Easy to use OTP 2FA check and generator, counter-based or time-based

• Fully compatible with standards
• Can manage 4 to 8 digits
• Can manage SHA1, SHA256 or SHA512 hash functions (as in RFC6238)

Compatible with Google Authenticator (default settings)

Using library

Get the library

From pip/pypi repository :

python3 -m pip install otppy

Or the old fashion way :
Copy the otppy folder in your working directory.

Use
from otppy import OTP in your Python program.

Examples

Example for code generation :

from otppy import OTP
this_otp = OTP.fromb32("BASE32SECRETHERE")
# TOTP return : [TOTPcode, Remaining Time in seconds]
totp = this_otp.TOTP()
print("TOTP Code :", totp[0])
print(totp[1], "sec left")

Example for code check :

# Initialize
from otppy import OTP
this_otp = OTP.fromb32("BASE32SECRETHERE")
# Check validity, return a boolean
totp_valid = this_otp.check_TOTP(string_code_received)

Interface methods of OTPpy OTP

otppy.OTP( secret, hashalg="sha1", digits=6, time_window=30 )
Create an OTP object from a raw secret.
Better to use with the class constructor "fromb32" :

otppy.fromb32( secret_base32, hashalg="sha1", digits=6, time_window=30 )
Load an OTP from parameters, including the shared secret as base32 encoded.
secret_base32 is the shared secret encoded in base32, optional padding.
hashalg is the hash algorithm to use : "sha1", "sha256" or "sha512".
digits is the integer for number of digits.
time_window is the time width of a time block in seconds (integer).
Note that the secret_base32 argument is enough to use a standard OTP setting (sha1, 6 digits and 30 seconds blocks).

.HOTP( counter )
Compute a HOTP code from the integer counter value.
Return the HOTP code as a string.

.TOTP( )
Compute a TOTP code from the current UTC machine time.
Return a duet list : the TOTP code as a string, and the remaining validity time in seconds.

.check_HOTP( counter_value, hotp_string )
Check the HOTP code string for the given values.
Return a boolean.

.check_TOTP( totp_string )
Check the TOTP code string (for the machine UTC time).
Return a boolean.

Form more details: see otppy/ code.

Internal tests

Test vectors from standards included in tests directory for pytest :

python3 -m pytest tests

Licence

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.