Ryanair's online check-in service fails to ensure users submit confidential details across a secure connection. As a result, travellers are invited to send confidential data across an unencrypted link.

"I checked every step when checking into a recent flight from Luton to Dublin to attend a funeral. At no point is SSL used, including when you're transmitting your name, passport details, or when they send you back your boarding pass," notes Register reader Jim H, who was the first to warn us of the issue.

Ryanair has fallen foul of the same type of problem that affected a British Gas website that allows homeowners to pay bills. As exclusively reported by El Reg earlier this month, consumers logging on to pay their bills through house.co.uk initially go through a secure server. But once they create an account and login they may be transferred to a payment server that fails to use an HTTPS connection, potentially exposing submitted credit card information to snooping.

Sometimes the use of frames on a site means users cannot see they are using a HTTPS link, and a padlock is not displayed, even though information is transferred over a secure link. The problems with Ryanair's check-in service go deeper than this.

We reported the apparent problems with the Ryanair website to the firm earlier this week. The airline is yet to respond to our requests for comment. ®

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