license key generator and validator used in libmdk
appid is "ProductName/CompanyName" from rc file. Rc file can be generated by visual studio, and qmake for qt apps(QMAKE_TARGET_PRODUCT/QMAKE_TARGET_COMPANY).
Rc can be encoded in utf8(default by qtcreator) if there are non ascii chars, and add #pragma code_page(65001)in rc (recommended for visual studio), or add rc compiler option`/c 65001``
Generate a key for windows:
keygen -gen -verify -appid "$(echo -n ProductName/CompanyName| iconv -t utf8)"
If rc is not encoded in utf8(may support more words in appid), must call setCodePage(cp)