Man Uses Clever Code To Ensure Only The Real Owner Could Contact Him

March 31, 2025

When one man found a wallet on a Saturday morning, he was determined to return it—but with police stations closed for the weekend, he had to get creative.

Instead of simply leaving the wallet in a drop box, where it wouldn’t be retrieved until Monday, he decided to give the rightful owner a chance to contact him directly—without exposing his own information to the public.

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Near the spot where he found the wallet, the man posted a flier with a brilliant twist.

The note contained a simple but clever cryptographic code: by entering their date of birth (which was on the ID in the wallet), the owner could unlock a sequence of numbers that revealed the man's phone number. This ensured that only the real owner, who could verify their ID, would be able to contact him—preventing random strangers from falsely claiming the wallet.

Later that day, the real owner called and was able to verify their identity, reuniting with their lost belongings.

He said he came up with the idea after watching a Computerphile video on cryptography and hashing. The popular YouTube channel is known for its insightful content on computer science, technology, and programming, making complex topics accessible to a broad audience.