#import <UIKit/UIKit.h>
@interface MYVendorToll : NSObject
+ (NSString *)getIDFV;
@end

#import "MYVendorToll.h"
#import "MYKeyChainTool.h"

@implementation MYVendorToll


+ (NSString *)getIDFV
{
 NSString *IDFV = (NSString *)[MYKeyChainTool load:@"IDFV"];

 if ([IDFV isEqualToString:@""] || !IDFV) {

  IDFV = [UIDevice currentDevice].identifierForVendor.UUIDString;
  [MYKeyChainTool save:@"IDFV" data:IDFV];
 }

 return IDFV;
}

@end

#import <Foundation/Foundation.h>

@interface MYKeyChainTool : NSObject


+ (void)save:(NSString *)service data:(id)data;
+ (id)load:(NSString *)service;
+ (void)deleteKeyData:(NSString *)service;

@end

#import "MYKeyChainTool.h"

@implementation MYKeyChainTool


+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
 return [NSMutableDictionary dictionaryWithObjectsAndKeys:
   (id)kSecClassGenericPassword,(id)kSecClass,
   service, (id)kSecAttrService,
   service, (id)kSecAttrAccount,
   (id)kSecAttrAccessibleAfterFirstUnlock,(id)kSecAttrAccessible,
   nil];
}

+ (void)save:(NSString *)service data:(id)data {
 //Get search dictionary
 NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
 //Delete old item before add new item
 SecItemDelete((CFDictionaryRef)keychainQuery);
 //Add new object to search dictionary(Attention:the data format)
 [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];
 //Add item to keychain with the search dictionary
 SecItemAdd((CFDictionaryRef)keychainQuery, NULL);
}

+ (id)load:(NSString *)service {
 id ret = nil;
 NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
 //Configure the search setting
 //Since in our simple case we are expecting only a single attribute to be returned (the password) we can set the attribute kSecReturnData to kCFBooleanTrue
 [keychainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
 [keychainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
 CFDataRef keyData = NULL;
 if (SecItemCopyMatching((CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
  @try {
   ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge NSData *)keyData];
  } @catch (NSException *e) {
   NSLog(@"Unarchive of %@ failed: %@", service, e);
  } @finally {
  }
 }
 if (keyData)
  CFRelease(keyData);
 return ret;
}

+ (void)deleteKeyData:(NSString *)service {
 NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
 SecItemDelete((CFDictionaryRef)keychainQuery);
}

@end