anastasis

Credential backup and recovery protocol and service
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validation_NL_BSN.c (1710B)


      1 /*
      2   This file is part of Anastasis
      3   Copyright (C) 2020, 2021 Anastasis SARL
      4 
      5   Anastasis is free software; you can redistribute it and/or modify it under the
      6   terms of the GNU General Public License as published by the Free Software
      7   Foundation; either version 3, or (at your option) any later version.
      8 
      9   Anastasis is distributed in the hope that it will be useful, but WITHOUT ANY
     10   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
     11   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
     12 
     13   You should have received a copy of the GNU General Public License along with
     14   Anastasis; see the file COPYING.GPL.  If not, see <http://www.gnu.org/licenses/>
     15 */
     16 /**
     17  * @file reducer/validation_NL_BSN.c
     18  * @brief Validation for Dutch Buergerservicenummern
     19  * @author Christian Grothoff
     20  */
     21 #include <string.h>
     22 #include <stdbool.h>
     23 
     24 
     25 /**
     26  * Function to validate a Dutch Social Security number.
     27  *
     28  * See https://nl.wikipedia.org/wiki/Burgerservicenummer
     29  *
     30  * @param bsn_number social security number to validate (input)
     31  * @return true if validation passed, else false
     32  */
     33 bool
     34 NL_BSN_check (const char *bsn_number);
     35 
     36 /* declaration to fix compiler warning */
     37 bool
     38 NL_BSN_check (const char *bsn_number)
     39 {
     40   static const int factors[] = {
     41     9, 8, 7, 6, 5, 4, 3, 2, -1
     42   };
     43   unsigned int sum = 0;
     44 
     45   if (strlen (bsn_number) != 9)
     46     return false;
     47   for (unsigned int i = 0; i<8; i++)
     48   {
     49     unsigned char c = (unsigned char) bsn_number[i];
     50 
     51     if ( ('0' > c) || ('9' < c) )
     52       return false;
     53     sum += (c - '0') * factors[i];
     54   }
     55   {
     56     unsigned char c = (unsigned char) bsn_number[8];
     57     unsigned int v = (c - '0');
     58 
     59     return (sum % 11 == v);
     60   }
     61 }