Arg0s1080
commented
5 years ago In this case mrz.checker works correctly. However, after seeing several Indian travel documents (Passports, Visas Type A and Visas type B) I have verified that what @tahajahangir explains may happen. For example:
Passports with errors in identifier and optional data hash:
However, in Indian visas identifier is printed correctly
Visa MRVB
Visa MRVA (although it seems that a final hash is used in this case)
(Images got from Google and pixilated to safeguard privacy)
Although it seems clear that this is a bad implementation of ICAO specifications, I think it would be a good idea to add the possibility of disabling checks for certain fields in future mrz.checker versions. (India is not the only country that does not comply with the specifications)
Meanwhile, the only solution I can think of for particular cases is that someone builds a class that inherits from TD1CodeChecker, TD2CodeChecker or TD3CodeChecker and overwrites some property. Recently someone consulted me by mail as adding a check for an additional hash and easily built a class called TD1DutchCodeChecker, inherited from TD1CodeChecker, which overwrote optional_data and optional_data_hash properties. Important note: The only requirement to make a child class in MRZ is that it must have this format: <DocumentType>*Code* . For example: TD1INDCodeChecker, TD1Type1CodeChecker, MRVAUKCodeGenerator, TD2BRACodeGenerator, TD3CodeCheckerBlahBlah or similar.
This is the class built for check Dutch Id Cards:
from ..base.countries_ops import *
from ..base.functions import hash_is_ok
from .td1 import TD1CodeChecker
import mrz.base.string_checkers as check
__all__ = ["TD1DutchCodeChecker", "code_list", "countries_list", "countries_code_list", "code_country_list",
"is_country", "is_code", "get_code", "get_country", "find_country"]
class TD1DutchCodeChecker(TD1CodeChecker):
"""
Check the string code of the machine readable zone for dutch TD1
__bool__() returns True if all fields are validated, False otherwise
Params:
mrz_string (str): MRZ string of td1s. Must be 90 uppercase characters long
check_expiry (bool): If it's set to True, it is verified and reported as warning that the
document is not expired and that expiry_date is not greater than 10 years
compute_warnings (bool): If it's set True, warnings compute as False
"""
def __init__(self, mrz_code: str, check_expiry=False, compute_warnings=False):
TD1CodeChecker.__init__(self, mrz_code, check_expiry, compute_warnings)
@property
def optional_data(self) -> bool:
"""Return True if the format of the optional data field is validated, False otherwise."""
s = self._optional_data
return True if check.is_empty(s) else self._report("id number format", check.is_printable(s))
@property
def optional_data_hash(self):
self._optional_data_hash = self.mrz_code.splitlines()[0][29]
self._optional_data = self.mrz_code.splitlines()[0][15: 29]
return self._report("id number hash", hash_is_ok(self._optional_data, self._optional_data_hash))
def _all_hashes(self) -> bool:
return (self.final_hash &
self.document_number_hash &
self.birth_date_hash &
self.expiry_date_hash &
self.optional_data_hash)Usage:
from mrz.checker.td1_dutch import TD1DutchCodeChecker
mrz_code = ("I<NLDARRE84NB20123456789<<<<<7\n" # '7' is an aditional hash not included in TD1 ICAO specifications
"9901236M3012235NLD<<<<<<<<<<<2\n"
"SMITH<<JOHN<JOEY<<<<<<<<<<<<<<")
checker = TD1DutchCodeChecker(mrz_code)
print("Check: %s" % checker)Output:
Check: True
ShadabShariff
Also, the first example MRZ, is an instance of another false-positive, where
optional data hashfails when optional-data is empty (all<) and optional-data-hash is<(instead of0). I think it may be an error according to specs, but exists in real-world.Originally posted by @tahajahangir in https://github.com/Arg0s1080/mrz/issues/1#issuecomment-439771574