参考文献

获取iOS设备唯一标识(UUID)并保存到钥匙串

Keychain简单理解和使用

---

1. UIDevice

会生成一个UUID，但随着APP删除也会改变。

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

2. 使用KeyChain

钥匙串是独立的，升级和删除都不会删除，因为它是存在手机中的钥匙串（iPhone估计很少人会去操作这里吧？）它也是被加密的。

打开KyeChain开关：
project -> targets -> Capabilities -> Keychain Sharing

复制下面两个类

• GetUUID
• KeyChainStore

KeyChainStore

#import <Foundation/Foundation.h>

@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 <Foundation/Foundation.h>

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

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

@implementation YKGetUUID
+(NSString *)getUUID
{
    NSString * strUUID = (NSString *)[KeyChainStore load:@"com.company.app.usernamepassword"];
    
    //首次执行该方法时，uuid为空
    if ([strUUID isEqualToString:@""] || !strUUID)
    {
        //生成一个uuid的方法
        CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);
        
        strUUID = (NSString *)CFBridgingRelease(CFUUIDCreateString (kCFAllocatorDefault,uuidRef));
        
        //将该uuid保存到keychain
        [KeyChainStore save:KEY_USERNAME_PASSWORD data:strUUID];
        
    }
    return strUUID;
}

@end

```

### 使用
```

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

```