Ruby 3.1.x and OpenSSL::Digest::DigestError

#ruby #openssl #rbenv

Came across this issue after upgrading Ruby to 3.1.0 in one of the apps I'm working on.

I use rbenv to manage Ruby versions, and it turns out they recently started building Ruby with OpenSSL 3.0 instead of OpenSSL 1.1.

OpenSSL 3.0, in turn, has retired a number of algorithms (including MD4 function, which was used in that app).

And hello! After the update, we call OpenSSL::Digest::MD4.hexdigest() and get this:
OpenSSL::Digest::DigestError, message: Digest initialization failed: initialization error

So, if you're using rbenv to update Ruby to 3.1.x and your code uses one of the retired algorithms, there's a chance you'll come across a similar issue.

A temporary workaround if you can't get rid of legacy code right away:

install Ruby with OpenSSL 1.1 (note I'm using brew here): export RUBY_CONFIGURE_OPTS="--with-openssl-dir=$(brew --prefix openssl@1.1)" && rbenv install 3.1.0
as an alternative, look into re-enabling MD4 in OpenSSL (this looks useful)

Another alternative would be to use an MD4 implementation in pure Ruby.