anastasis

Credential backup and recovery protocol and service
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validation_FR_INSEE.c (2333B)

      1 /*
      2   This file is part of Anastasis
      3   Copyright (C) 2022 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_FR_INSEE.c
     18  * @brief Validation for French INSEE Numbers
     19  * @author Christian Grothoff
     20  */
     21 #include <string.h>
     22 #include <stdbool.h>
     23 #include <stdio.h>
     24 
     25 
     26 /**
     27  * Function to validate a French INSEE number.
     28  *
     29  * See https://en.wikipedia.org/wiki/INSEE_code
     30  *
     31  * Note that we do not implement checks on the month
     32  * and also allow non-binary prefixes.  Corsican numbers carry 2A or 2B in
     33  * the department field and are accepted.
     34  *
     35  * @param insee_number social security number to validate (input)
     36  * @return true if validation passed, else false
     37  */
     38 bool
     39 FR_INSEE_check (const char *insee_number);
     40 
     41 /* declaration to fix compiler warning */
     42 bool
     43 FR_INSEE_check (const char *insee_number)
     44 {
     45   char pfx[14];
     46   unsigned long long num;
     47   unsigned int cc;
     48   char dum;
     49 
     50   if (strlen (insee_number) != 15)
     51     return false;
     52   memcpy (pfx,
     53           insee_number,
     54           13);
     55   pfx[13] = '\0';
     56   /* Corsica carries a letter in the department field (positions 5-6): the
     57      official rule is to substitute 2A -> 19 and 2B -> 18 before the mod-97,
     58      since the remaining digits alone would collide between the two. */
     59   if ('2' == pfx[5])
     60   {
     61     if ('A' == pfx[6])
     62     {
     63       pfx[5] = '1';
     64       pfx[6] = '9';
     65     }
     66     else if ('B' == pfx[6])
     67     {
     68       pfx[5] = '1';
     69       pfx[6] = '8';
     70     }
     71   }
     72   if (1 !=
     73       sscanf (pfx,
     74               "%llu%c",
     75               &num,
     76               &dum))
     77     return false;
     78   if (1 !=
     79       sscanf (&insee_number[13],
     80               "%u%c",
     81               &cc,
     82               &dum))
     83     return false;
     84   if (97 - cc != num % 97)
     85     return false;
     86   return true;
     87 }