There are some more technical details in the extended blog post – <a href="https://www.benthamsgaze.org/2016/08/02/do-you-know-what-youre-paying-for-how-contactless-cards-are-still-vulnerable-to-relay-attack/" rel="nofollow">https://www.benthamsgaze.org/2016/08/02/do-you-know-what-you...</a>