Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of Hem and Haw

Hem and Haw by Tin Le

Looks for hashed email addresses (HEMs) and other personal information sent to third parties.

ExperimentalExperimental
0 (0 reviews)0 (0 reviews)
1 User1 User
You'll need Firefox to use this extension
Download Firefox and get the extension
Download file

Extension Metadata

Screenshots
Input page for PIISearching for hash transmissionsHash transmissions detectedGraph generated in see all results
About this extension
https://tincangit.github.io/hemandhaw-study/

About Hem and Haw:
This browser extension monitors when hashes of your personally identifiable information (like emails or phone numbers) are sent to third parties.

How it works:
- You enter email addresses, phone numbers, and/or other details, and press submit.
- Hem and Haw creates hashes of these inputs.
- When a matching hash is detected being sent to a third party, Hem and Haw takes note and logs to our server:
Type of data (e.g., email),
Hash type (e.g., MD5),
Third party's hostname,
Originating website's hostname,
Where in the transmission (HTTP request) the hash was found,
Whether you use an ad blocker (based on your response).

At any point, you can stop Hem and Haw from searching for hashes, add/modify/delete the PII to search for, and see the logs of transmissions.

What Hem and Haw does NOT collect:
- Your actual personal data (e.g., email addresses or phone numbers),
- HTTP request details and data,
- Any other personal information. Your IP address is also not collected by our server.

IMPORTANT NOTE:
Hem and Haw will clear all results when you clear all history.
Rated 0 by 0 reviewers
Log in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and dataLearn more

Required permissions:

  • Download files and read and modify the browser’s download history
  • Access browsing history
  • Access browser tabs

Optional permissions:

  • Access your data for all websites
More information
Add-on Links
  • Support site
Version
3.5.5
Size
1.44 MB
Last updated
a month ago (Aug 16, 2025)
Related Categories
  • Privacy & Security
License
MIT License
Privacy Policy
Read the privacy policy for this add-on
Version History
  • See all versions
Tags
  • privacy
Add to collection
Report this add-on
Release notes for 3.5.5
  • Now reports browser
More extensions by Tin Le
  • There are no ratings yet

  • There are no ratings yet

  • There are no ratings yet

  • There are no ratings yet

  • There are no ratings yet

  • There are no ratings yet

Go to Mozilla's homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Browsers

  • Desktop
  • Mobile
  • Enterprise

Products

  • Browsers
  • VPN
  • Relay
  • Monitor
  • Pocket
  • Bluesky (@firefox.com)
  • Instagram (Firefox)
  • YouTube (firefoxchannel)
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike License v3.0 or any later version.