iOSが取得した一意の識別子

参考文献
iOSデバイス固有ID(UUID)を取得し、キー列に保存
Keychainの簡単な理解と使用
1. UIDevice
UUIDが生成されますが、アプリの削除に伴って変更されます.

NSString *identifierForVendor = [[UIDevice currentDevice].identifierForVendor UUIDString];

2.KeyChainの使用
キーホルダーは独立しており、アップグレードも削除も削除されません.携帯電話に存在するキーホルダーなので(iPhoneではここを操作する人は少ないのではないでしょうか?)暗号化されています.
KyeChainスイッチをオンにします:project -> targets -> Capabilities -> Keychain Sharing次の2つのクラスをコピー

GetUUID

KeyChainStore

KeyChainStore

#import 

@interface YKKeyChainStore : NSObject
+ (void)save:(NSString *)service data:(id)data;
+ (id)load:(NSString *)service;
+ (void)deleteKeyData:(NSString *)service;
@end

#import "YKKeyChainStore.h"

@implementation YKKeyChainStore
+ (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);
}

GetUUID

#import 

@interface YKGetUUID : NSObject
+(NSString *)getUUID;
@end

#import "GetUUID.h"
#import "KeyChainStore.h"
#define  KEY_USERNAME_PASSWORD @"com.company.app.usernamepassword" //   
#define  KEY_USERNAME @"com.company.app.username" //   
#define  KEY_PASSWORD @"com.company.app.password" //   

@implementation YKGetUUID
+(NSString *)getUUID
{
    NSString * strUUID = (NSString *)[KeyChainStore load:@"com.company.app.usernamepassword"];
    
    //        ，uuid  
    if ([strUUID isEqualToString:@""] || !strUUID)
    {
        //    uuid   
        CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);
        
        strUUID = (NSString *)CFBridgingRelease(CFUUIDCreateString (kCFAllocatorDefault,uuidRef));
        
        //  uuid   keychain
        [KeyChainStore save:KEY_USERNAME_PASSWORD data:strUUID];
        
    }
    return strUUID;
}

@end

```

###   
```

 NSLog(@"----%@",[YKGetUUID getUUID]);

```