Lobster Programming

Sep 14, 2026 · Databases

Three-Field Schema for Encrypted Phone Number Queries by Last Four Digits

The article analyzes flawed approaches for querying encrypted phone numbers by last four digits — memory decryption, ciphertext fuzzy matching, partial encryption, and mapping tables — and presents a three-field design (full ciphertext, masked display, indexed last-four plaintext) that ensures compliance, security, and millisecond query performance at million-user scale.