import calendar
import datetime
import hashlib
import time
from typing import Any, Optional, Union
from . import utils
from .otp import OTP
[docs]class TOTP(OTP):
"""
Handler for time-based OTP counters.
"""
def __init__(
self,
s: str,
digits: int = 6,
digest: Any = None,
name: Optional[str] = None,
issuer: Optional[str] = None,
interval: int = 30,
) -> None:
"""
:param s: secret in base32 format
:param interval: the time interval in seconds for OTP. This defaults to 30.
:param digits: number of integers in the OTP. Some apps expect this to be 6 digits, others support more.
:param digest: digest function to use in the HMAC (expected to be SHA1)
:param name: account name
:param issuer: issuer
"""
if digest is None:
digest = hashlib.sha1
self.interval = interval
super().__init__(s=s, digits=digits, digest=digest, name=name, issuer=issuer)
[docs] def at(self, for_time: Union[int, datetime.datetime], counter_offset: int = 0) -> str:
"""
Accepts either a Unix timestamp integer or a datetime object.
To get the time until the next timecode change (seconds until the current OTP expires), use this instead:
.. code:: python
totp = pyotp.TOTP(...)
time_remaining = totp.interval - datetime.datetime.now().timestamp() % totp.interval
:param for_time: the time to generate an OTP for
:param counter_offset: the amount of ticks to add to the time counter
:returns: OTP value
"""
if not isinstance(for_time, datetime.datetime):
for_time = datetime.datetime.fromtimestamp(int(for_time))
return self.generate_otp(self.timecode(for_time) + counter_offset)
[docs] def now(self) -> str:
"""
Generate the current time OTP
:returns: OTP value
"""
return self.generate_otp(self.timecode(datetime.datetime.now()))
[docs] def verify(self, otp: str, for_time: Optional[datetime.datetime] = None, valid_window: int = 0) -> bool:
"""
Verifies the OTP passed in against the current time OTP.
:param otp: the OTP to check against
:param for_time: Time to check OTP at (defaults to now)
:param valid_window: extends the validity to this many counter ticks before and after the current one
:returns: True if verification succeeded, False otherwise
"""
if for_time is None:
for_time = datetime.datetime.now()
if valid_window:
for i in range(-valid_window, valid_window + 1):
if utils.strings_equal(str(otp), str(self.at(for_time, i))):
return True
return False
return utils.strings_equal(str(otp), str(self.at(for_time)))
[docs] def provisioning_uri(
self, name: Optional[str] = None, issuer_name: Optional[str] = None, image: Optional[str] = None
) -> str:
"""
Returns the provisioning URI for the OTP. This can then be
encoded in a QR Code and used to provision an OTP app like
Google Authenticator.
See also:
https://github.com/google/google-authenticator/wiki/Key-Uri-Format
"""
return utils.build_uri(
self.secret,
name if name else self.name,
issuer=issuer_name if issuer_name else self.issuer,
algorithm=self.digest().name,
digits=self.digits,
period=self.interval,
image=image,
)
[docs] def timecode(self, for_time: datetime.datetime) -> int:
"""
Accepts either a timezone naive (`for_time.tzinfo is None`) or
a timezone aware datetime as argument and returns the
corresponding counter value (timecode).
"""
if for_time.tzinfo:
return int(calendar.timegm(for_time.utctimetuple()) / self.interval)
else:
return int(time.mktime(for_time.timetuple()) / self.interval)