Pwned Passwords

Last August, I launched a little feature within Have I Been Pwned (HIBP) I called Pwned Passwords. This was a list of 320 million passwords from a range of different data breaches which organisations could use to better protect their own systems. How? NIST explains: When processing requests to establish and change memorized secrets, verifiers SHALL compare the prospective secrets against a list that contains values known to be commonly-used, expected, or compromised. They then go on to recommend that passwords "obtained from previous breach corpuses" should be disallowed and that the service should "advise the subscriber that they need to select a different secret". This makes a lot of sense when you think about it:...

Edit 1: The following day, I loaded another set of passwords which has brought this up to 320M. More on why later on. Edit 2: The API model described below has subsequently been discontinued in favour of the k-anonymity model launched with V2. Last week I wrote about Passwords Evolved: Authentication Guidance for the Modern Era with the aim of helping those building services which require authentication to move into the modern era of how we think about protecting accounts. In that post, I talked about NIST's Digital Identity Guidelines which were recently released. Of particular interest to me was the section advising organisations to block subscribers from using passwords that have previously appeared in a data breach. Here's the...