Hashed Email Passthrough

Freestar's hashed email (HEM) passthrough enables publishers to share a hashed version of a user's email with vendors.

Overview

Freestar's hashed email (HEM) passthrough enables publishers to share a hashed version of a user's email with vendors, such as Prebid User ID modules and bidders.

Expanding deterministic user IDs is a big opportunity for publishers to boost ad inventory value, especially with declining third-party cookie coverage.

📘

Please ensure compliance with any applicable regulations regarding disclosures and obtain required consent before sharing user data with upstream vendors.

Passing Unhashed Email Addresses

Call the following function to pass a user's plaintext email address. Freestar will hash the email before passing it to upstream vendors.

freestar.queue.push(function(){
    freestar.identity.setIdentity({
        email:EMAIL_ADDRESS
    });
});

Passing Hashed Email Addresses

When providing a hashed email address, please note the following:

• Validate the email against using a regular expression
• Remove leading and trailing spaces
• Convert all ASCII characters to lowercase
• Hash the email using SHA1, SHA256 and/or MD5 hash are supported (SHA256 is required)
• In gmail.com email addresses, remove the following characters from the username part of the email address:
  • Periods (ASCII code 46). For example, normalize [e-mail] to [e-mail].
  • Plus signs (ASCII code 43) and all subsequent characters. For example, normalize [e-mail] to [e-mail].

Call the following function and pass an object containing one or more hashes of each email address:

freestar.queue.push(function(){
    freestar.identity.setIdentity({ 
        hashes: {
            sha1: SHA1_HASH,
            sha256: SHA256_HASH,
            md5: MD5_HASH
        } 
    });
});

Testing

The function creates a cookie in session storage called fs.ident and holds the hashes that were passed through. To test the implementation simply look for the fs.ident cookie in session storage as in the screenshot below.

What's Next 

LiveIntent Identity Resolution