Skip to content
Private Preview
Join Waitlist →

Breach Checker

Check if your credentials appeared in known data breaches using k-anonymity

Updated 5 Feb 20265 min readAuthor: Redactorr Support Team · [email protected]Last reviewed: March 2026

Outcome

Check credential exposure using the safest available path, understand what the result means, and choose the next action without pasting unnecessary secrets.

Your progress

Mark each step as you complete it. This is saved only in this browser.

0 / 3 steps complete

Before you start

Use a test value or a credential you are authorised to check.
Know whether you are checking an email, password, API key, or account identifier.
Be ready to rotate or reset anything that appears exposed.

Visual frame

Review asset

Breach checker storyboard

Synthetic breach checker frame only. It uses fake credentials and avoids implying live breach confirmation or external exposure checks.

InputSynthetic only
ReviewRisk signal
ActionRotate if needed

Synthetic frame

Checker input

Start with fake values.

Sample valuefake-secret-123
Real passwordDo not paste first
PurposeUnderstand signals
A checker should be understood with fake values before sensitive material is used.

Breach-check decision frame

A narrow credential-risk flow that checks only what is needed and routes exposed values to action.

InputOne authorised value or reviewed detection.
SignalExposure match is a risk signal, not full incident proof.
ActionRotate, revoke, reset, monitor, or investigate.

Guided steps

Follow the task, then check the result.

Choose the smallest safe thing to check

Only check the value needed for the question. Do not paste a full document, log, or credential bundle when the tool only needs one value or one detection result.

Single credential check instead of full document paste.
Success check: You are checking one authorised value or one reviewed detection.

Read the exposure result as a risk signal

A breach result means the value may need rotation, reset, or investigation. It does not prove who used it or whether the current account was compromised.

Result state split into no match, match found, and action needed.
Success check: You know whether the result requires no action, monitoring, reset, or rotation.

Act in the owning system

Use the account, provider, or key-management system that owns the credential to rotate, revoke, reset, or investigate. Redactorr can guide the check; it is not the system of record for the credential.

Breach result routed to rotate, revoke, reset, monitor, or investigate.
Success check: The exposed value has an owner and a next action outside the KB.

Branch questions

Completion check

You checked only the value needed for the risk question.
You know what the result does and does not prove.
Any exposed value has a rotation, reset, revoke, or investigation owner.

Support boundary

Support can use by default

  • Value category such as email, password, token, or account identifier.
  • Result state such as no match, match found, or unable to check.
  • No raw credential value by default.
  • Intent ID
  • Article slug
  • App route
  • Browser and viewport

Requires your consent

  • User-written description
  • Email address
  • Explicit attachment
  • Redacted sample
  • Support bundle previewed to the user

Not collected by default

  • Raw original document text
  • Full local file paths
  • Pasted private content
  • Unmasked screenshots
  • Replay capture

Safe support summary

Copy a scrubbed handoff.

Redactorr KB support summary

Article: /knowledge-base/breach-checker
Selected issue: The checker result is unclear or does not match the value type you selected.
Playbook progress: 0/3 steps marked complete

Safe context to include:
- Value category such as email, password, token, or account identifier.
- Result state such as no match, match found, or unable to check.
- No raw credential value by default.
- Intent ID
- Article slug
- App route
- Browser and viewport

Requires explicit consent:
- User-written description
- Email address
- Explicit attachment
- Redacted sample
- Support bundle previewed to the user

Do not include by default:
- Raw original document text
- Full local file paths
- Pasted private content
- Unmasked screenshots
- Replay capture

User note:
- Describe the step and symptom without pasting raw document text, secrets, files, or restoration material.

Article details

Breach Checker: A Background Check for Your Passwords

Ever wonder if your password was leaked in a data breach? That nagging feeling that maybe, just maybe, your credentials are floating around on the dark web?

That's what Breach Checker is for.

Think of it like a background check for your passwords. You paste in a password, email, or API key, and within seconds you'll know if it's been compromised in any of the thousands of known data breaches.

How It Works (The Privacy-First Way)

Here's the clever part: your actual password stays local during detection and redaction.

When you check a password, Redactorr uses a technique called "k-anonymity" that's used by security researchers worldwide. Instead of sending your password to a server (bad idea!), it only sends the first 5 characters of a cryptographic hash.

The server responds with all hashes that start with those 5 characters, and your browser compares them locally. It's like asking "do you have anyone whose name starts with 'Joh'?" instead of "do you have John Smith?"

The server never sees your actual password. Ever.

What You'll Learn

After checking a credential, you'll see:

  • Breach Status: Whether it appeared in known breaches
  • Breach Count: How many times it's been seen (higher = worse)
  • What to Do: Clear steps to rotate/change the credential

Real-World Use Cases

Before sharing credentials with a new team member: Check if the shared password has been compromised before distributing it.

Auditing old API keys: That GitHub token from 2019? Check if it showed up in any leaks before deciding to rotate it.

Due diligence for compliance: Some security frameworks require proof that credentials haven't been breached. This gives you that proof.

Browser-Local Detection

This bears repeating: browser-local. The password you're checking is hashed in your browser using SHA-1, and only the first 5 characters of that hash are sent to HaveIBeenPwned's API.

Your actual password? Stays on your machine. Always.

Still stuck?

Copy a safe article handoff.

Start support with the article, the issue, and safe context. Raw document text, files, restoration material, and unredacted screenshots stay out unless you explicitly choose otherwise.

Support can start here
  • Article slug
  • Selected issue
  • Screen name
  • Action name
Redactorr support case

Source: Article playbook: breach-checker
Route: /knowledge-base/breach-checker
Selected issue: The checker result is unclear or does not match the value type you selected.

Safe context:
- Value category such as email, password, token, or account identifier.
- Result state such as no match, match found, or unable to check.
- No raw credential value by default.
- Article slug
- Selected issue
- Screen name or article section
- Action name
- Browser and viewport

Only include with explicit consent:
- User-written description
- Email address
- Explicit attachment
- Redacted sample
- Support bundle previewed to the user

Do not include by default:
- Raw original document text
- Full local file paths
- Pasted private content
- Unmasked screenshots
- Replay capture
- Hidden diagnostic uploads

User note:
- Describe what you tried and what happened. Do not paste raw document text, secrets, files, restoration material, or unredacted screenshots.

Support case builder

One case format, wherever you start.

This is the same support case shape used by diagnostics and article handoffs.

Safe to include
  • Value category such as email, password, token, or account identifier.
  • Result state such as no match, match found, or unable to check.
  • No raw credential value by default.
  • Article slug
  • Selected issue
  • Screen name or article section
Consent boundary

Private material belongs behind an explicit consent step, not in the initial case.

6 default exclusions

Before you copy0/4 ready
Open safe support guide