Source code for pyotp.utils

import unicodedata
from hmac import compare_digest
from typing import Dict, Optional, Union
from urllib.parse import quote, urlencode, urlparse


[docs]def build_uri(secret: str, name: str, initial_count: Optional[int] = None, issuer: Optional[str] = None, algorithm: Optional[str] = None, digits: Optional[int] = None, period: Optional[int] = None, image: Optional[str] = None) -> str: """ Returns the provisioning URI for the OTP; works for either TOTP or HOTP. This can then be encoded in a QR Code and used to provision the Google Authenticator app. For module-internal use. See also: https://github.com/google/google-authenticator/wiki/Key-Uri-Format :param secret: the hotp/totp secret used to generate the URI :param name: name of the account :param initial_count: starting counter value, defaults to None. If none, the OTP type will be assumed as TOTP. :param issuer: the name of the OTP issuer; this will be the organization title of the OTP entry in Authenticator :param algorithm: the algorithm used in the OTP generation. :param digits: the length of the OTP generated code. :param period: the number of seconds the OTP generator is set to expire every code. :param image: optional logo image url :returns: provisioning uri """ # initial_count may be 0 as a valid param is_initial_count_present = (initial_count is not None) # Handling values different from defaults is_algorithm_set = (algorithm is not None and algorithm != 'sha1') is_digits_set = (digits is not None and digits != 6) is_period_set = (period is not None and period != 30) otp_type = 'hotp' if is_initial_count_present else 'totp' base_uri = 'otpauth://{0}/{1}?{2}' url_args = {'secret': secret} # type: Dict[str, Union[None, int, str]] label = quote(name) if issuer is not None: label = quote(issuer) + ':' + label url_args['issuer'] = issuer if is_initial_count_present: url_args['counter'] = initial_count if is_algorithm_set: url_args['algorithm'] = algorithm.upper() # type: ignore if is_digits_set: url_args['digits'] = digits if is_period_set: url_args['period'] = period if image: image_uri = urlparse(image) if image_uri.scheme != 'https' or not image_uri.netloc or not image_uri.path: raise ValueError('{} is not a valid url'.format(image_uri)) url_args['image'] = image uri = base_uri.format(otp_type, label, urlencode(url_args).replace("+", "%20")) return uri
[docs]def strings_equal(s1: str, s2: str) -> bool: """ Timing-attack resistant string comparison. Normal comparison using == will short-circuit on the first mismatching character. This avoids that by scanning the whole string, though we still reveal to a timing attack whether the strings are the same length. """ s1 = unicodedata.normalize('NFKC', s1) s2 = unicodedata.normalize('NFKC', s2) return compare_digest(s1.encode("utf-8"), s2.encode("utf-8"))