When your leaked password lookup in a data breach, criminals have a huge advantage because they can sell your information to other people or use it to attack you. Having your password leaked could even expose your whole organization to ransomware and other attacks. This is why it’s important to identify any passwords that have been leaked as quickly as possible.

Leaked Password Lookup

Fortunately, there are several ways to check if your password has been compromised. You can use a service like Have I Been Pwned, or sign up for a breach notification service to alert you when your email or username appears in a data leak. Or you can use a password manager, like iolo technologies ByePass, that instantly identifies any leaked passwords and lets you change them within the system.

Troy Hunt’s new tool works differently than existing services in that it doesn’t send your entire SHA-1 hash to a server; doing so would expose too much information and make it easier for malicious actors to reconstruct your original password. Instead, it sends the first five characters of your SHA-1 hash to the server, which returns a list of all leaked password hashes that start with those same five characters.

The service can also search passwords directly from your website, software or app with a simple API, allowing you to detect breaches live during registration, login and other sensitive actions. This could reduce your risk of breach and improve user experience by avoiding delays caused by network calls, though the performance impact will depend on how many searches you need to perform at any given moment.