SHA-1 can not be configured

here is link of my repo:- GitHub - Rkgarg2127/git_cpp

[compile] /usr/bin/ld: CMakeFiles/git.dir/src/Server.cpp.o: in function sha_file(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)': [compile] Server.cpp:(.text+0x112e): undefined reference to SHA1’
[compile] collect2: error: ld returned 1 exit status
[compile] gmake[2]: *** [CMakeFiles/git.dir/build.make:97: git] Error 1
[compile] gmake[1]: *** [CMakeFiles/Makefile2:83: CMakeFiles/git.dir/all] Error 2
[compile] gmake: *** [Makefile:91: all] Error 2

Hi @Rkgarg2127, sorry if I missed it, but have you implemented the SHA1 function?

SHA1((unsigned char *)data.c_str(), data.size(), hash);
I have done this line 167 of server.cpp

My C++ is a bit rusty, but it seems like you’re only calling SHA1, and it doesn’t appear to be implemented within the codebase?

so what can be done how to implement it??
I have searched online and it is generally used this way.