Workaround RubyGems' SSL errors on Ruby for Windows (RubyInstaller)
UPDATE 2016-12-01: Please refer to the official guide instead of this process.
UPDATE 2014-12-21: RubyGems 1.8.30, 2.0.15 and 2.2.3 have been released. It requires manual installation, please see instructions below.
If you reached this page, means you've hit this SSL error when trying to pull updates from RubyGems:
SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
This error is produced by changes in rubygems.org infrastructure, please keep reading to better understand it.
If you're one of those too long, didn't read just skip to the guide on how to workaround it.
For those who are not familiar with SSL and certificates, there are many parts that make secure serving of content possible.
SSL certificates are used on the website, which are obtained from a certificate authority (CA) and generated from a private key, along with its respective signature.
Normally and up until a few months ago, private key signatures used SHA-1 as way to provide a digest (or checksum) of the private key without distributing the key itself (remember, needs to remain private).
SHA-1 has been encountered weak and lot of web servers and sites have been upgrading towards SHA-2 (specifically SHA256 or higher) in order to prepare for the browsers changes.
The particular case of RubyGems (the command line tool) is that it requires to bundle inside of its code the trust certificates, which allow RubyGems to establish a connection with the servers even when base operating system is unable to verify the identity of them.
Up until a few months ago, this certificate was provided by one CA, but newer certificate is provided by a different one.
Because of this, existing installations of RubyGems would have to been updated before the switch of the certificate and give enough time for the change to spread (and people to update).
As what normally happens with software, things might get out of sync and coordinate such effort, to the size and usage of rubygems.org is almost impossible.
I've described this on Issue #1050
We had discussed also on IRC, and patches and backports were provided to all major branches of RubyGems: 1.8, 2.0, 2.2, 2.4 and 2.6
Please understand this could happen to anyone. Release multiple versions of any software in a short span of time and be very time sensitive is highly complicated.
Even if we have official releases of any of the versions that correct the issue, it will not be possible install those via RubyGems (chicken-egg problem described before).
RubyGems has covered this in the official guides, please follow the instructions here
gem install --local
You should now be able to install gems normally.
If you still experience any issue, please search for any existing issue on RubyGems Issue Tracker or report a new one.