An email address run through a one-way hash function (SHA-256 by convention) so that it can be matched between parties without exposing the address itself. Hashed emails are the most common key for customer list uploads, clean room matches, and alternative identifiers such as Unified ID 2.0. Hashing is not anonymization: anyone holding the same email can produce the same hash.
Related terms
Cite this entry:
Agency Echelon. "Hashed Email." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/hashed-email/