Overview
What this tool is designed to do
This helper lets you test a password against the public Have I Been Pwned breach corpus without revealing the
password to CyberLife Coach. It is useful for checking whether a password is already known to attackers, which
is a strong signal that you should retire it everywhere it is used.
It is aimed at individuals, families, small organizations, and security conscious users who want a quick
privacy respecting way to spot obviously unsafe passwords before reusing them on important accounts.
Local hashing in your browser
k-Anonymity range query to HIBP
When this checker is a good fit
The Secure Password Breach Checker works best when you:
- Are evaluating a personal password before reusing it on a new site.
- Are helping a friend or family member understand why a password should be replaced.
- Want a safer way to demonstrate breach checking during a workshop or training session.
It should not be treated as an authorization to keep using a password. A password that does not appear in
breach records can still be weak, guessable, or reused across multiple services.
Important habit.
The safest practice is to use a unique, random password for every account and store them in a reputable
password manager. The breach checker is there to catch obvious problems, not to certify that a password is
strong enough.
How it works
Privacy first design
The checker performs all hashing in your browser using SHA-1. The full hash and the plaintext password stay
on your device. The page then sends only the first five characters of the uppercase hash prefix to the Have
I Been Pwned range API and compares the suffixes locally.
In practice, the flow looks like this.
- You type a password into the field on the breach checker page.
- Your browser computes its SHA-1 hash and displays the prefix and suffix for transparency.
- Only the first five characters of that hash prefix are sent to HIBP’s range endpoint.
- HIBP returns a list of matching suffixes and counts for that prefix.
- The page checks locally whether your full hash appears in that list and shows a result.
Safe use and limitations
The tool is careful about what it sends, but there are still important boundaries to respect:
-
Do not enter shared, administrative, or work managed passwords unless your organization explicitly allows
this kind of check.
-
A “not found in breaches” result does not guarantee safety. A short or common password can still be guessed
quickly even if it has never been leaked before.
-
Results depend on third party breach data. New breaches may not yet be included, and some older breaches may
never be captured.
The checker is a quick indicator, not an intrusion detection system or a full credential management solution.
You should still enable multi factor authentication where possible and rotate passwords if you suspect any
compromise.
Use it as a warning light.
Treat a positive breach hit as a red light for that password and a strong nudge to change it everywhere it
was used. Treat a clean result as a yellow light that still requires good hygiene and unique passwords.