An implementation of SM2 signature creation and verification is provided. Header files and library files of OpenSSL 1.1.1 are needed while compiling and linking. OpenSSL website is: https://www.openssl.org

    SM2 is a cryptographic algorithm based on elliptic curves. It is defined in the following standards of China:

• GB/T32918.1-2016,
• GB/T32918.2-2016,
• GB/T32918.3-2016,
• GB/T32918.4-2016,
• GM/T 0003-2012.

    SM2 signature creation and verification are supported in OpenSSL 1.1.1. In the source package, "/crypto/sm2/sm2_sign.c" is a good example. Digital signature creation and verification are encapsulated in an abstract level called EVP. In some cases using EVP interfaces to compute SM2 signature and verify it is a little inconvenient. An implementation bypassing invoking OpenSSL EVP interfaces is given here.

Work with OpenSSL 3.0.0 ?
    The codes here is designed to be run with OpenSSL 1.1.1. If the codes are compiled with OpenSSL 3.0.0 on Linux platform, many warnings are shown. But it can be run with OpenSSL 3.0.0. Test with CentOS Linux 7.9 + gcc 4.8.5 + OpenSSL 3.0.0 has passed. The codes cannot be compiled on Windows platform with OpenSSL 3.0.0.