Erlang OTP 20 breaks JsonWebToken.Algorithm.Rsa.validate_key_size/1

[BrendonPierson]

It appears the latest erlang release has removed :crypto.mpint/1. This is causing the JsonWebToken.Algorithm.Rsa.validate_key_size/1 to break. I think we will need a work around for validating key size.

[lachezar]

As a temporary solution I created a erl file with the mpint/1 implementation. I am not sure if there is a proper function in crypto or in other modules which can replace mpint/1 (I am not experienced with Erlang), but I can make a PR if this solution is good enough.

lachezar@e9b0faf

[BrendonPierson]

I've played around with it a bit and it looks like :crypto.mpint/1 was just moved to :ssh_bits.mpint/1. I'm not sure on the best practice here, but It's probably wise to run some logic that picks the correct version based on the erlang version.

Here is a simple workaround that runs a check for the Erlang version and picks the right function -> #21

[lachezar]

Looks very clean and nice!!