Is openssl required for a local .gem file + gem install?

Today at work, I had to compile a ruby from source into my home dir
(Linux system; had no superuser access).

That built ruby had no openssl.

I did not have enough time to investigate deeper; at home I compile
everything from source but I also have full freedom over all paths.
I think with openssl it may be a bit more complicated to build but
I assume there is some --with-openssl option or something like that.

Anyway, what I was wondering is that I was then trying to install a
local .gem file via “gem install --user-install ./*.gem” - something
like that.

And the error message was something along this line:

“Unable to require openssl, install OpenSSL and rebuild ruby”

But that confused me, because why would I need openssl when
the .gem was already available locally? I did it the other way
by extracting the .gem, then using good old setup.rb instead
and it worked too.

So here my question:

  • Is openssl required for (local) gems to work and be installed?

Perhaps I have done something wrong, that may also be, but I can
not for the sake of me figure out why openssl would be required
for “gem” to work on local .gem files.