Thinking through this: If we add cryptographic signing to BT outgoing webhooks, the clients receiving the webhooks would 1. need to update code to verify the signature and 2. we'd need a mechanism to generate and provide a shared secret? does that match up with what you're thinking?

Not sure the best to share the signing secret, I suppose somewhere in the BT admin dashboard. Stripe provides the signing secret in the stripe CLI. I also dug up the code stripe is using the sign their webhooks for fun:

      # Computes a webhook signature given a time (probably the current time),
      # a payload, and a signing secret.
      def self.compute_signature(timestamp, payload, secret)
        raise ArgumentError, "timestamp should be an instance of Time" \
          unless timestamp.is_a?(Time)
        raise ArgumentError, "payload should be a string" \
          unless payload.is_a?(String)
        raise ArgumentError, "secret should be a string" \
          unless secret.is_a?(String)

        timestamped_payload = "#{timestamp.to_i}.#{payload}"
        OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new("sha256"), secret,
                                timestamped_payload)
      end

@bhumi1102 Verifying the signature is totally optional, so no one will need to update any webhook processing code. It'll just give them a good option for validating the webhook originated at the right place and has not been tampered with.