@interface NSUUIDManager : NSObject

+ (NSString*)UUID;
@end

#import <Security/Security.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>

@implementation NSUUIDManager

static const char kKeychainUUIDItemIdentifier[]  = "UUID";



+ (NSString*)UUID
{
    NSString *uuid = [NSUUIDManager getUUIDFromKeyChain];
    if (!uuid) {

        NSString *sysVersion = [UIDevice currentDevice].systemVersion;
        CGFloat version = [sysVersion floatValue];

        if (version >= 7.0) {
            uuid = [NSUUIDManager get_IdentifierForVendor];
        }else{

            uuid = @"NULL";
        }

        [NSUUIDManager setUUIDToKeyChain:uuid];
    }


    return uuid;
}
+ (NSString*)get_IdentifierForVendor
{
    return [[UIDevice currentDevice].identifierForVendor UUIDString];
}


#pragma mark -
#pragma mark Helper Method for make identityForVendor consistency

+ (NSString*)getUUIDFromKeyChain
{
    NSMutableDictionary *dictForQuery = [[NSMutableDictionary alloc] init];
    [dictForQuery setValue:(id)kSecClassGenericPassword forKey:(id)kSecClass];

    // set Attr Description for query
    [dictForQuery setValue:[NSString stringWithUTF8String:kKeychainUUIDItemIdentifier]
                    forKey:(NSString *)kSecAttrDescription];

    // set Attr Identity for query
    NSData *keychainItemID = [NSData dataWithBytes:kKeychainUUIDItemIdentifier
                                            length:strlen(kKeychainUUIDItemIdentifier)];
    [dictForQuery setObject:keychainItemID forKey:(id)kSecAttrGeneric];

    [dictForQuery setValue:(id)kCFBooleanTrue forKey:(id)kSecMatchCaseInsensitive];
    [dictForQuery setValue:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
    [dictForQuery setValue:(id)kCFBooleanTrue forKey:(id)kSecReturnData];

    OSStatus queryErr   = noErr;
    NSData   *uuidValue = nil;
    NSString *uuid      = nil;
    queryErr = SecItemCopyMatching((CFDictionaryRef)dictForQuery, (CFTypeRef*)&uuidValue);

    NSMutableDictionary *dict = nil;
    [dictForQuery setValue:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];
    queryErr = SecItemCopyMatching((CFDictionaryRef)dictForQuery, (CFTypeRef*)&dict);

    if (queryErr == errSecItemNotFound) {
        NSLog(@"KeyChain Item: %@ not found!!!", [NSString stringWithUTF8String:kKeychainUUIDItemIdentifier]);
    }
    else if (queryErr != errSecSuccess) {
        NSLog(@"KeyChain Item query Error!!! Error code:%d", queryErr);
    }
    if (queryErr == errSecSuccess) {
        NSLog(@"KeyChain Item: %@", uuidValue);

        if (uuidValue) {
            uuid = [NSString stringWithUTF8String:uuidValue.bytes];

        }
     
    }


    return uuid;
}

+ (BOOL)setUUIDToKeyChain:(NSString*)uuid
{
    NSMutableDictionary *dictForAdd = [[NSMutableDictionary alloc] init];

    [dictForAdd setValue:(id)kSecClassGenericPassword forKey:(id)kSecClass];
    [dictForAdd setValue:[NSString stringWithUTF8String:kKeychainUUIDItemIdentifier] forKey:(NSString *)kSecAttrDescription];

    [dictForAdd setValue:@"UUID" forKey:(id)kSecAttrGeneric];

    // Default attributes for keychain item.
    [dictForAdd setObject:@"" forKey:(id)kSecAttrAccount];
    [dictForAdd setObject:@"" forKey:(id)kSecAttrLabel];



    const char *uuidStr = [uuid UTF8String];
    NSData *keyChainItemValue = [NSData dataWithBytes:uuidStr length:strlen(uuidStr)];
    [dictForAdd setValue:keyChainItemValue forKey:(id)kSecValueData];

    OSStatus writeErr = noErr;
    if ([NSUUIDManager getUUIDFromKeyChain]) {        // there is item in keychain
        [NSUUIDManager updateUUIDInKeyChain:uuid];

        return YES;
    }
    else {          // add item to keychain
        writeErr = SecItemAdd((CFDictionaryRef)dictForAdd, NULL);
        if (writeErr != errSecSuccess) {
            NSLog(@"Add KeyChain Item Error!!! Error Code:%d", writeErr);


            return NO;
        }
        else {
            NSLog(@"Add KeyChain Item Success!!!");

            return YES;
        }
    }


    return NO;
}

+ (BOOL)removeUUIDFromKeyChain
{
    NSMutableDictionary *dictToDelete = [[NSMutableDictionary alloc] init];

    [dictToDelete setValue:(id)kSecClassGenericPassword forKey:(id)kSecClass];

    NSData *keyChainItemID = [NSData dataWithBytes:kKeychainUUIDItemIdentifier length:strlen(kKeychainUUIDItemIdentifier)];
    [dictToDelete setValue:keyChainItemID forKey:(id)kSecAttrGeneric];

    OSStatus deleteErr = noErr;
    deleteErr = SecItemDelete((CFDictionaryRef)dictToDelete);
    if (deleteErr != errSecSuccess) {
        NSLog(@"delete UUID from KeyChain Error!!! Error code:%d", deleteErr);

        return NO;
    }
    else {
        NSLog(@"delete success!!!");
    }

    return YES;
}

+ (BOOL)updateUUIDInKeyChain:(NSString*)uuid
{

    NSMutableDictionary *dictForQuery = [[NSMutableDictionary alloc] init];

    [dictForQuery setValue:(id)kSecClassGenericPassword forKey:(id)kSecClass];

    NSData *keychainItemID = [NSData dataWithBytes:kKeychainUUIDItemIdentifier
                                            length:strlen(kKeychainUUIDItemIdentifier)];
    [dictForQuery setValue:keychainItemID forKey:(id)kSecAttrGeneric];
    [dictForQuery setValue:(id)kCFBooleanTrue forKey:(id)kSecMatchCaseInsensitive];
    [dictForQuery setValue:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
    [dictForQuery setValue:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];

    NSDictionary *queryResult = nil;
    SecItemCopyMatching((CFDictionaryRef)dictForQuery, (CFTypeRef*)&queryResult);
    if (queryResult) {

        NSMutableDictionary *dictForUpdate = [[NSMutableDictionary alloc] init];
        [dictForUpdate setValue:[NSString stringWithUTF8String:kKeychainUUIDItemIdentifier] forKey:(NSString *)kSecAttrDescription];
        [dictForUpdate setValue:keychainItemID forKey:(id)kSecAttrGeneric];

        const char *uuidStr = [uuid UTF8String];
        NSData *keyChainItemValue = [NSData dataWithBytes:uuidStr length:strlen(uuidStr)];
        [dictForUpdate setValue:keyChainItemValue forKey:(id)kSecValueData];

        OSStatus updateErr = noErr;

        // First we need the attributes from the Keychain.
        NSMutableDictionary *updateItem = [NSMutableDictionary dictionaryWithDictionary:queryResult];


        // Second we need to add the appropriate search key/values.
        // set kSecClass is Very important
        [updateItem setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];

        updateErr = SecItemUpdate((CFDictionaryRef)updateItem, (CFDictionaryRef)dictForUpdate);
        if (updateErr != errSecSuccess) {
            NSLog(@"Update KeyChain Item Error!!! Error Code:%d", updateErr);

            return NO;
        }
        else {
            NSLog(@"Update KeyChain Item Success!!!");

            return YES;
        }
    }


    return NO;
}



@end

#pragma mark -┏━━━━━━━━━━━━━━━━设置设备的唯一标示符━━━━━━━━━━━━━━━━━┓

#pragma mark -IdentifierForVendor(厂商标识符)
    NSString *uuid = [[[UIDevice currentDevice] identifierForVendor ]UUIDString];
    NSLog(@"%@",uuid);
#pragma mark -将IdentifierForVendor(厂商标识符)存储在钥匙串里
    NSString *uuid_2 = [NSUUIDManager UUID];

    NSLog(@"%@",uuid_2);


#pragma mark -┗━━━━━━━━━━━━━━━━设置设备的唯一标示符━━━━━━━━━━━━━━━━━┛

uuid 删除后在安装，每次值不一致
uuid_2 删除后在安装，每次保持一致

注：
1.NSUUIDManager.m

屏幕快照 2016-03-28 17.50.35.png

屏幕快照 2016-03-28 17.52.36.png