IOS ID card verification detailed introduction and sample code

-(BOOL)checkUserIDCard:(NSString *)userID 
{ 
  //Exclude any length of 18  if (!=18) { 
    return NO; 
  } 
   
  //Calibration format  NSString *regex2 = @"^(^[1-9]\\d{7}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])\\d{3}$)|(^[1-9]\\d{5}[1-9]\\d{3}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])((\\d{4})|\\d{3}[Xx])$)$"; 
  NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2]; 
  BOOL flag = [identityCardPredicate evaluateWithObject:userID]; 
   
  if (!flag) { 
    return flag;  //Format error  }else { 
    //The format is correct and it is legal to determine whether it is legal.    //Save the first 17-bit weighting factors in the array    NSArray * idCardWiArray = @[@"7", @"9", @"10", @"5", @"8", @"4", @"2", @"1", @"6", @"3", @"7", @"9", @"10", @"5", @"8", @"4", @"2"]; 
     
    //This is the 11-bit remainder and verification code that may be generated after dividing by 11, and is also saved into an array    NSArray * idCardYArray = @[@"1", @"0", @"10", @"9", @"8", @"7", @"6", @"5", @"4", @"3", @"2"]; 
     
    // Used to save the sum of the first 17 bits after the weighting factor    NSInteger idCardWiSum = 0; 
    for(int i = 0;i < 17;i++){ 
      NSInteger subStrIndex = [[userID substringWithRange:NSMakeRange(i, 1)] integerValue]; 
      NSInteger idCardWiIndex = [[idCardWiArray objectAtIndex:i] integerValue]; 
      idCardWiSum+= subStrIndex * idCardWiIndex; 
    } 
     
    // Calculate the location of the array where the verification code is located    NSInteger idCardMod=idCardWiSum%11; 
     
    //Get the last ID number    NSString * idCardLast= [userID substringWithRange:NSMakeRange(17, 1)]; 
     
    //If it is equal to 2, it means that the verification code is 10, and the last digit of the ID number should be X    if(idCardMod==2){ 
      if([idCardLast isEqualToString:@"X"]||[idCardLast isEqualToString:@"x"]){ 
        return YES; 
      }else{ 
        return NO; 
      } 
    }else{ 
      //Match the calculated verification code with the last ID number. If it is consistent, it means that it is passed, otherwise it is an invalid ID number.      if([idCardLast isEqualToString: [idCardYArray objectAtIndex:idCardMod]]){ 
        return YES; 
      }else{ 
        return NO; 
      } 
    } 
  } 
} 

//Regularly match the user ID number 15 or 18 digits-(BOOL)validateIDCardNumber:(NSString *)value { 
 
  value = [value stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; 
  NSInteger length =0; 
  if (!value) { 
    return NO; 
  }else { 
    length = ; 
    //Not satisfied with 15-bit and 18-bit, that is, the ID card error    if (length !=15 && length !=18) { 
      return NO; 
    } 
  } 
  // Province code  NSArray *areasArray = @[@"11",@"12", @"13",@"14", @"15",@"21", @"22",@"23", @"31",@"32", @"33",@"34", @"35",@"36", @"37",@"41", @"42",@"43", @"44",@"45", @"46",@"50", @"51",@"52", @"53",@"54", @"61",@"62", @"63",@"64", @"65",@"71", @"81",@"82", @"91"]; 
   
  // Detect the provincial identity administrative region code  NSString *valueStart2 = [value substringToIndex:2]; 
  BOOL areaFlag =NO; //Identify the province code is correct  for (NSString *areaCode in areasArray) { 
    if ([areaCode isEqualToString:valueStart2]) { 
      areaFlag =YES; 
      break; 
    } 
  } 
   
  if (!areaFlag) { 
    return NO; 
  } 
   
  NSRegularExpression *regularExpression; 
  NSUInteger numberofMatch; 
   
  int year =0; 
  //Split into 15-digit and 18-digit ID cards for verification  switch (length) { 
    case 15: 
      //Get the number corresponding to the year      year = [value substringWithRange:NSMakeRange(6,2)].intValue +1900; 
     
      if (year %4 ==0 || (year %100 ==0 && year %4 ==0)) { 
        //Create regular expression NSRegularExpressionCaseInsensitive: a case-insensitive pattern        regularExpression = [[NSRegularExpression alloc]initWithPattern:@"^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}$" 
          options:NSRegularExpressionCaseInsensitive error:nil];//Test the legality of the date of birth      }else { 
        regularExpression = [[NSRegularExpression alloc]initWithPattern:@"^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}$" 
        options:NSRegularExpressionCaseInsensitive error:nil];//Test the legality of the date of birth      } 
      //Use regular expressions to match strings NSMatchingReportProgress: Call the block callback after finding the longest matching string.      numberofMatch = [regularExpression numberOfMatchesInString:value 
                                options:NSMatchingReportProgress 
                                 range:NSMakeRange(0, )]; 
       
      if(numberofMatch >0) { 
        return YES; 
      }else { 
        return NO; 
      } 
    case 18: 
      year = [value substringWithRange:NSMakeRange(6,4)].intValue; 
      if (year %4 ==0 || (year %100 ==0 && year %4 ==0)) { 
        regularExpression = [[NSRegularExpression alloc]initWithPattern:@"^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}[0-9Xx]$" options:NSRegularExpressionCaseInsensitive error:nil];//Test the legality of the date of birth      }else { 
        regularExpression = [[NSRegularExpression alloc]initWithPattern:@"^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}[0-9Xx]$" options:NSRegularExpressionCaseInsensitive error:nil];//Test the legality of the date of birth      } 
      numberofMatch = [regularExpression numberOfMatchesInString:value 
                                options:NSMatchingReportProgress 
                                 range:NSMakeRange(0, )]; 
       
       
      if(numberofMatch >0) { 
        //1: Calculation method of verification code: The 17-digit number of ID card numbers are multiplied by different coefficients respectively.  The coefficients from the first position to the seventeenth position are: 7-9-10-5-8-4-2-1-6-3-7-9-10-5-8-4-2.  Add the result of multiplying these 17-digit numbers and coefficients.         
        int S = [value substringWithRange:NSMakeRange(0,1)].intValue*7 + [value substringWithRange:NSMakeRange(10,1)].intValue *7 + [value substringWithRange:NSMakeRange(1,1)].intValue*9 + [value substringWithRange:NSMakeRange(11,1)].intValue *9 + [value substringWithRange:NSMakeRange(2,1)].intValue*10 + [value substringWithRange:NSMakeRange(12,1)].intValue *10 + [value substringWithRange:NSMakeRange(3,1)].intValue*5 + [value substringWithRange:NSMakeRange(13,1)].intValue *5 + [value substringWithRange:NSMakeRange(4,1)].intValue*8 + [value substringWithRange:NSMakeRange(14,1)].intValue *8 + [value substringWithRange:NSMakeRange(5,1)].intValue*4 + [value substringWithRange:NSMakeRange(15,1)].intValue *4 + [value substringWithRange:NSMakeRange(6,1)].intValue*2 + [value substringWithRange:NSMakeRange(16,1)].intValue *2 + [value substringWithRange:NSMakeRange(7,1)].intValue *1 + [value substringWithRange:NSMakeRange(8,1)].intValue *6 + [value substringWithRange:NSMakeRange(9,1)].intValue *3; 
         
        //2: Use the addition and divide by 11 to see what the remainder is?  The remainder can only have 11 numbers: 0-1-2-3-4-5-6-7-8-9-10        int Y = S %11; 
        NSString *M =@"F"; 
        NSString *JYM =@"10X98765432"; 
        M = [JYM substringWithRange:NSMakeRange(Y,1)];// 3: Get the check bit        //4: Check the ID's check bit        if ([M isEqualToString:[value substringWithRange:NSMakeRange(17,1)]]) { 
          return YES; 
        }else { 
          return NO; 
        } 
         
      }else { 
        return NO; 
      } 
    default: 
      return NO; 
  } 
}