Security 框架

// 第一步：根据ServiceID获取对应配置
- (NSMutableDictionary *)getKeyChainQueryByServiceID:(NSString *)serviceID {
    //这个就和keychainitemwrapper里面提前预设了参数一样
    return [NSMutableDictionary dictionaryWithObjectsAndKeys:
            (id)kSecClassGenericPassword,(id)kSecClass,
            serviceID,(id)kSecAttrService,
            serviceID,(id)kSecAttrAccount,
            (id)kSecAttrAccessibleAfterFirstUnlock,(id)kSecAttrAccessible,
            nil];
}
// 第二步：存
- (void)saveObject:(id)obj toService:(NSString *)serviceID
{
    //Get search dictionary
    NSMutableDictionary *keychainQuery = [self getKeyChainQueryByServiceID:serviceID];
    //Delete old item before add new item
    SecItemDelete((CFDictionaryRef)keychainQuery);
    //Add new object to search dictionary(Attention:the data format)
    [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:obj requiringSecureCoding:YES error:nil] forKey:(id)kSecValueData];
    ;
    //Add item to keychain with the search dictionary
    SecItemAdd((CFDictionaryRef)keychainQuery, NULL);
    
}

// 第三步：取
- (id)fetService:(NSString*)serviceID {
    
        id ret = nil;
        NSMutableDictionary *keychainQuery = [self getKeyChainQueryByServiceID:serviceID];
        [keychainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
        [keychainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
        NSData *keyData = NULL;
        if(SecItemCopyMatching((CFDictionaryRef)keychainQuery, (CFTypeRef*)(void*)&keyData) == noErr) {
            @try {
                ret = [NSKeyedUnarchiver unarchivedObjectOfClass:[NSString class] fromData:keyData error:nil];
            }
            @catch (NSException *exception) {
                
            }
            @finally {
            }
        }
    return ret;
}