A single leaked hint exposed the CIA’s most puzzling code. But dozens of the world’s toughest ciphers are still waiting to be solved.

You could do worse than to confuse the meanings of "code" and "cipher"—even cryptographers sometime use the terms as though they had the same meaning. There is, however, a definite distinction between ...

The cryptic text of a 250-year-old secret society has finally been translated. Researchers from North America and Europe used a powerful computer program to break the code. Daniel Hajek reports on how ...

SAN FRANCISCO -- Experts have solved the code in the "340 Cipher" sent to the San Francisco Chronicle in 1969 by the Zodiac Killer, the elusive figure who terrorized California's Bay Area decades ago ...