About the Secure Password Breach Checker
The Secure Password Breach Checker helps you see whether a password has appeared in known data breaches while keeping the raw password on your device. It uses the Have I Been Pwned (HIBP) range API and the k-Anonymity model, sending only the first five characters of the password’s SHA-1 hash rather than the password itself.
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.
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.
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.
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.
This Secure Password Breach Checker is a client side educational tool intended to help you understand whether a password appears in the public Have I Been Pwned breach corpus. All hashing is performed in your browser and only a partial SHA-1 hash prefix is sent to the HIBP range API endpoint. Neither your full hash nor your plaintext password are transmitted to CyberLife Coach or stored by this page.
Legal disclaimerThe checker does not guarantee that a password is safe or secure and should not be relied upon as your only security control. A password that does not appear in breach data can still be weak, reused, or exposed by other means. Results are based on third party data and are provided “as is” without any warranty of completeness, accuracy, or fitness for a particular purpose. This page does not provide legal, financial, or professional security advice. Always follow modern password best practices, use unique credentials per site, enable multi factor authentication where available, and consult your organization’s security team or a qualified professional before changing high value or work related passwords.