'Mixed feelings': AI cracks centuries-old ciphers

Napoleon Bonaparte ordered the wartime missive written in code, creating a puzzle that went unsolved for more than 200 years -- until AI cracked it in a matter of hours.

Tomokiyo said that since mid-September, most of the ciphers on his list have been cracked using AI.

"There remain some tough problems" which could stay an enigma for years to come, because there is less relevant data available to help AI figure them out, the 58-year-old told AFP.

"I'm excited long-time problems are now solved, but on the other hand, I have mixed feelings, because AI seems to have solved these difficult problems so easily," he said.