.rar or .zip saved to SQL Server

Yes - just read it as a sequence of bytes and save it in a varbinary(max) column. You retrieve it the same way, and can then save it as a zip / rar file again.

However, I would strongly suggest against it: zip / rar files tend to be used for very large objects, and most databases have a maximum size limit as well as causing a lot of database traffic when you insert, update or select them. It might make a lot more sense to keep them in a separate file-system based folder instead, under a temporary name (a Guid for example) and store the original name and the Guid path in the DB instead.