+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {

    return [NSMutableDictionary dictionaryWithObjectsAndKeys:

            (__bridge id)kSecClassGenericPassword,(__bridge id)kSecClass,

//存储类型、密码、私钥等等

            service, (__bridge id)kSecAttrService,

//干什么的

            service, (__bridge id)kSecAttrAccount,

//账户名称：区别用户用的

            (__bridge id)kSecAttrAccessibleAfterFirstUnlock,(__bridge id)kSecAttrAccessible,

            nil];

//信息访问的授权方式：手机是否解锁

}

 

[keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge id)kSecValueData];

//添加存储值

 

SecItemAdd((__bridge CFDictionaryRef)keychainQuery, NULL);

 

 

[keychainQuery setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnData];

    [keychainQuery setObject:(__bridge id)kSecMatchLimitOne forKey:(__bridge id)kSecMatchLimit];

//查询时数据的过滤方式