UserSig is a security signature designed by Tencent Cloud to prevent attackers from accessing your Tencent Cloud account.
Currently, Tencent Cloud services including TRTC, Chat, and MLVB all use this security mechanism. To use these services, you must pass in three parameters – SDKAppID, UserID, and UserSig – to the initialization or login API of the corresponding SDK.
SDKAppID identifies an application, and UserID identifies a user. UserSig is a security signature calculated based on SDKAppID and UserID using the HMAC SHA256 encryption algorithm. Attackers cannot use your Tencent Cloud traffic as long as they don’t have UserSig.
See the figure below for how UserSig is calculated. Basically, it involves hashing crucial information such as SDKAppID, UserID, and ExpireTime.
// UserSig formula, in which `secretkey` is the key used to calculate UserSig
How do I calculate UserSig during debugging or demo run?
If you want to quickly run the demo to try out TRTC features, you can generate UserSig either using our client-side sample code or in the console:
Caution
These two methods are only suitable for debugging. It’s not recommended for official launch because SECRETKEY in the client code (especially on the web) may be easily decompiled and reversed. If your key is leaked, attackers can steal your Tencent Cloud traffic.
The correct method is to deploy the UserSig calculation code on your project server so that your application can request from your server a UserSig that is calculated whenever one is needed.
Calculating UserSig using client-side sample code
1. Get the SDKAppID and key:
1. Log in to the TRTC console and click Application Management.
2. Find your application and click Configuration.
3. In Basic information, SDKSecretKey is the key used to calculate UserSig.
4. Copy the key.
2. Calculate UserSig:
We offer source code for calculating UserSig on different platforms.
We provide an open-source module called GenerateTestUserSig in the TRTC SDK sample code. Set the three member variables of SDKAPPID, EXPIRETIME, and SECRETKEY, and you will be able to call genTestUserSig() to obtain the UserSig and get started quickly.
Generating UserSig in the console
1. Log in to the TRTC console, select Application Management on the left sidebar, and click UserSig generation.
2. Select your application (SDKAppID) from the drop-down list. A secret key will be generated automatically.
3. Enter the user ID.
4. Click Generate.
How do I calculate UserSig in a production environment?
In a production environment, server-side UserSig calculation offers stronger protection against key leakage because it is more difficult to hack a server than it is to reverse engineer an application. See below for detailed directions:
1. Before your application calls the initialization API of the SDK, request UserSig from your server.
2. Your server will calculate a UserSig based on the SDKAppID and UserID. The calculation source code is provided above.
3. The server returns the UserSig to your application.
4. Your application sends the UserSig to the SDK through a specific API.
5. The SDK submits the SDKAppID + UserID + UserSig to the Tencent Cloud server for verification.
6. Tencent Cloud verifies the validity of the UserSig.
7. If the UserSig is valid, services will be provided to the TRTC SDK.
To simplify your implementation process, we provide UserSig calculation source code (new algorithm) in multiple languages.
UserSig calculation source code using the legacy algorithm
To simplify the signature calculation process and facilitate your use of Tencent Cloud services, on July 19, 2019, TRTC switched from ECDSA-SHA256 to the new signature algorithm HMAC-SHA256. This means that all applications (SDKAppID) created on and after July 19, 2019 will use the new HMAC-SHA256 algorithm.
If your application (SDKAppID) was created before July 19, 2019, you can continue to use the old signature algorithm, whose source code can be downloaded below.
