DOCS(README): add SM reference guide

README.md

@@ -1,20 +1,22 @@
 ![Tencent Kona](https://user-images.githubusercontent.com/56812395/68106974-413b0700-ff1e-11e9-9128-ab1ad57283d1.png)
 ## Tencent Kona 8
-Tencent Kona is a no-cost, production-ready distribution of the Open Java Development Kit (OpenJDK), Long-Term Support(LTS) with quarterly updates. 
+Tencent Kona is a no-cost, production-ready distribution of the Open Java Development Kit (OpenJDK), Long-Term Support(LTS) with quarterly updates.
 
 Kona serves as the default JDK at Tencent internally, optimized for extreme-scale of Big Data, Machine Learning and Cloud Computing workload. It is also used to build and maintain a Tencent supported version of OpenJDK for Tencent customers and partners who wish to use OpenJDK to run their applications.
 
+Kona also implements China's cryptographic algorithms, including SM2, SM3 and SM4, and secure communication protocol TLCP (or SMSSL). For more details on theses features, please refer to [the reference guide](https://tencent.github.io/konajdk/sm/).
+
 ## Using Tencent Kona 8
 
-Tencent Kona currently supports Linux/x86_64, Linux/Aarch64, Windows/x86_64, Mac/x86_64. 
+Tencent Kona currently supports Linux/x86_64, Linux/Aarch64, Windows/x86_64, Mac/x86_64.
 
 ## License
 
 Tencent Kona is under the same licensing terms as the upstream OpenJDK project. It is clearly a "friendly fork". Tencent intends to contribute on the continuous success of Java and upstream as many enhancements as possible. Please read the file: "LICENSE".
 
 ## Introduction, Installation Guide and User Guide
 
-Please read [https://github.com/Tencent/TencentKona-8/wiki](https://github.com/Tencent/TencentKona-8/wiki) 
+Please read [https://github.com/Tencent/TencentKona-8/wiki](https://github.com/Tencent/TencentKona-8/wiki)
 
 ### The binary for Installation
 
@@ -23,4 +25,3 @@ Please access [https://github.com/Tencent/TencentKona-8/releases](https://github
 ## Issues Report and Discussion
 
 Please use [https://github.com/tencent/TencentKona-8/issues](https://github.com/tencent/TencentKona-8/issues)
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