oc唯一标时一部设备

#import MyKeyChainManager.h

@implementation MyKeyChainManager : NSObject

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
return [NSMutableDictionary dictionaryWithObjectsAndKeys:
(__bridge_transfer id)kSecClassGenericPassword,(__bridge_transfer id)kSecClass,
service, (__bridge_transfer id)kSecAttrService,
service, (__bridge_transfer id)kSecAttrAccount,
(__bridge_transfer id)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transfer 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((__bridge_retained CFDictionaryRef)keychainQuery);
//Add new object to search dictionary(Attention:the data format)
[keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge_transfer id)kSecValueData];
//Add item to keychain with the search dictionary
SecItemAdd((__bridge_retained CFDictionaryRef)keychainQuery, NULL);
}

+ (id)load:(NSString *)service {
id ret = nil;
NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
//Configure the search setting
[keychainQuery setObject:(id)kCFBooleanTrue forKey:(__bridge_transfer id)kSecReturnData];
[keychainQuery setObject:(__bridge_transfer id)kSecMatchLimitOne forKey:(__bridge_transfer id)kSecMatchLimit];
CFDataRef keyData = NULL;
if (SecItemCopyMatching((__bridge_retained CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
@try {
ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge_transfer NSData *)keyData];
} @catch (NSException *e) {
NSLog(@Unarchive of %@ failed: %@, service, e);
} @finally {
}
}
return ret;
}

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

@end

#import

@interface MyUUIDManager: NSObject

+(void)saveUUID:(NSString *)uuid;

+(NSString *)getUUID;

+(void)deleteUUID;

@end

.m文件来实现它：

#import MyUUIDManager.h
#import MyKeyChainManager.h

@implementation MyUUIDManager

static NSString * const KEY_IN_KEYCHAIN = @com.myuuid.uuid;

+(void)saveUUID:(NSString *)uuid{
if (uuid && uuid.length > 0) {
[MyKeyChainManager save:KEY_IN_KEYCHAIN data:uuid];
}
}

+(NSString *)getUUID{
//先获取keychain里面的UUID字段，看是否存在
NSString *uuid = (NSString *)[MyKeyChainManager load:KEY_IN_KEYCHAIN];

//如果不存在则为首次获取UUID，所以获取保存。
if (!uuid || uuid.length == 0) {
CFUUIDRef puuid = CFUUIDCreate( nil );

CFStringRef uuidString = CFUUIDCreateString( nil, puuid );

uuid = [NSString stringWithFormat:@%@, uuidString];

[self saveUUID:uuid];

CFRelease(puuid);

CFRelease(uuidString);
}

return uuid;
}

+(void)deleteUUID{
[MyKeyChainManager delete:KEY_IN_KEYCHAIN];
}

@end

测试数据：

NSString *uuid = [MyUUIDManager getUUID];
NSLog(@uuid: %@,uuid);