module ExoBasic

see: gist.github.com/ostinelli/1770a93d5c01376728c9

https://stackoverflow.com/questions/50077065/
        get-elliptic-curve-public-key-from-private-key-using-ruby-openssl
https://stackoverflow.com/questions/38934615/
        not-sure-how-to-generate-an-ecdsa-signature-given-a-private-key-and-a-message

see: docs.github.com/en/developers/webhooks-and-events/securing-your-webhooks

https://github.com/square/connect-api-examples/blob/master/connect-examples/v1/ruby/webhooks.rb