113 lines
3.6 KiB
Python
113 lines
3.6 KiB
Python
# aadhaar.py - functions for handling Indian personal identity numbers
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#
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# Copyright (C) 2017 Srikanth L
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# Copyright (C) 2021 Gaurav Chauhan
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301 USA
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"""Aadhaar (Indian personal identity number).
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Aadhaar is a 12 digit identification number that can be obtained by Indian
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citizens, non-residents passport holders of India and resident foreign
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nationals. The number is issued by the Unique Identification Authority of
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India (UIDAI).
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Aadhaar is made up of 12 digits where the last digits is a check digit
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calculated using the Verhoeff algorithm. The numbers are generated in a
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random, non-repeating sequence and do not begin with 0 or 1.
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More information:
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* https://en.wikipedia.org/wiki/Aadhaar
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* https://web.archive.org/web/20140611025606/http://uidai.gov.in/UID_PDF/Working_Papers/A_UID_Numbering_Scheme.pdf
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>>> validate('234123412346')
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'234123412346'
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>>> validate('234123412347')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> validate('123412341234') # number should not start with 0 or 1
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Traceback (most recent call last):
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...
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InvalidFormat: ...
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>>> validate('643343121')
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Traceback (most recent call last):
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...
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InvalidLength: ...
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>>> validate('222222222222') # number cannot be a palindrome
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Traceback (most recent call last):
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...
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InvalidFormat: ...
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>>> format('234123412346')
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'2341 2341 2346'
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>>> mask('234123412346')
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'XXXX XXXX 2346'
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"""
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from __future__ import annotations
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import re
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from stdnum import verhoeff
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from stdnum.exceptions import *
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from stdnum.util import clean
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aadhaar_re = re.compile(r'^[2-9][0-9]{11}$')
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"""Regular expression used to check syntax of Aadhaar numbers."""
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def compact(number: str) -> str:
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"""Convert the number to the minimal representation. This strips the
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number of any valid separators and removes surrounding whitespace."""
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return clean(number, ' -').strip()
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def validate(number: str) -> str:
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"""Check if the number provided is a valid Aadhaar number. This checks
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the length, formatting and check digit."""
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number = compact(number)
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if len(number) != 12:
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raise InvalidLength()
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if not aadhaar_re.match(number):
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raise InvalidFormat()
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if number == number[::-1]:
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raise InvalidFormat() # Aadhaar cannot be a palindrome
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verhoeff.validate(number)
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return number
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def is_valid(number: str) -> bool:
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"""Check if the number provided is a valid Aadhaar number. This checks
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the length, formatting and check digit."""
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try:
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return bool(validate(number))
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except ValidationError:
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return False
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def format(number: str) -> str:
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"""Reformat the number to the standard presentation format."""
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number = compact(number)
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return ' '.join((number[:4], number[4:8], number[8:]))
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def mask(number: str) -> str:
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"""Masks the first 8 digits as per Ministry of Electronics and
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Information Technology (MeitY) guidelines."""
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number = compact(number)
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return 'XXXX XXXX ' + number[-4:]
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