How to Save Check box data

I Created UITableView, the data in that TableView loads from web service .And I insert a check box in the cell.

I would like to save the data of checked cell.

And also when i reopen the application the selected check boxes are remaining as it is like previous.

This is my myTable.m

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath       *)indexPath {
     static NSString *cell1=@"aa";
     CustomCell *cell=[tableView dequeueReusableCellWithIdentifier:cell1];

    if (cell==nil) {

      cell=[[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cell1];
      NSArray *cellArray=[[NSBundle mainBundle]loadNibNamed:@"CustomCell" owner:nil options:nil];

      for (UIView *view in cellArray) {

         if([view isKindOfClass:[CustomCell class]])
           {
            cell = (CustomCell*)view;             

        }
        }
}

    //cell.textLabel.text=[array objectAtIndex:indexPath.row];
cell.labelcell.text=[array objectAtIndex:indexPath.row];

return cell;

}

CustomCell.h

  #import <UIKit/UIKit.h>

   @interface CustomCell : UITableViewCell{

    BOOL isSelected;
     }


    @property (strong, nonatomic) IBOutlet UILabel *labelcell;

    @property (strong, nonatomic) IBOutlet UIButton *checkButton;

    - (IBAction)checkboxAction:(id)sender;

    @end

CustomCell.m

    - (IBAction)checkboxAction:(id)sender {

       NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];

        if(!isSelected){

          [checkButton setImage:[UIImage imageNamed:@"checked.png"]
                 forState:UIControlStateNormal];

         isSelected = YES;
         [defaults setBool:isSelected forKey:@"boxIsChecked"];

         }
         else if (isSelected){

           [checkButton setImage:[UIImage imageNamed:@"empty-check.png"]
                 forState:UIControlStateNormal];

        isSelected = NO;
        [defaults setBool:isSelected forKey:@"boxIsChecked"];

        }

        [defaults synchronize];
        }
        -(void)checkTheBox{

          if(!isSelected){
            [checkButton setImage:[UIImage imageNamed:@"empty-check.png"]
                 forState:UIControlStateNormal];
          }
           else if (isSelected){

            [checkButton setImage:[UIImage imageNamed:@"checked.png"]
                 forState:UIControlStateNormal];
          }

          }

Am try to use NSUserDefaults but it is applying for total rows in the table. I would like to apply for individual row and also want to save that row data. Can any one Help me.