As I said, I may be wrong (I've never used slackware in my life), but it seems to me that soft-linking your existing library to the library required by silfyconnect worked. Now silfyconnect is obviously stopping at the next library it needs, which is libcrypto.so.4 -- it seems to me you should just repeat the process, by typing:
~# sudo ln -s /usr/lib/libcrypto.so /usr/lib/libcrypto.so.4
I assume you know what soft-linking is -- it's just "redirecting" the file system to just load the plain libcrypto.so (which you have) whenever a program requests to load libcrypto.so.4 (the version 4 which you don't have). If you do have the needed plain libraries in your /usr/lib directory (or elsewhere on your system - just issue find / -name libcrypto*
) you should IMHO just soft-link every *.so.4 library required by silfyconnect to its existing plain *.so version following the format given above. If however, you don't have the plain libraries on your system, then you'll probably have to google out which package contains them, and then download and install the package.