Thank you for your responses, Rafael and Josh!
Unfortunately, we don't have SSL/TLS setup for our instance. We are starting to take a more serious look at implementing it this would help us meet our project requirements.
Rafael - I'm a little confused by your description about your use of Marketo webhook, would you be able to clarfiy? Did you capture the trial registration data with a Marketo form or an external form? If an external form was used, what triggered the webhook to be called (API call to smart campaign, web page visit, etc)? We have looked into using Webhooks to sent the trial registration data to the product to generate the trial, but there are concerns about possible delays in relaying the information between systems and getting the prospect directly into the trial on form submit.