create sm2 private key
openssl genpkey -algorithm EC -pkeyopt ec_paramgen_curve:sm2 -out sm2key.pem
view sm2 key
openssl ec -in sm2key.pem -noout -text
sign sm2 with sm3 and distid ( aka userid or uid )
openssl dgst -sm3 -hex -sign sm2key.pem -sigopt distid:userid file_to_sign
gmssl sm2 sign
./gmssl sm2sign
usage: sm2sign -key pem -pass str [-id str] [-in file] [-out file]
