Is this RSA algorithm?

[Git]

As Kerlingen suggests you need the correct sig file for the compiler used. If it is an unusual compiler you will have to compile it yourself. One you have the .lib used to link in the openssl functions, use IDA's Flirt tools to convert .lib to .sig. Put the .sig in the sig directory and proceed to apply that sig to your disassembly. Many openssl functions should now be identified with the correct names.

Git