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.

The BitLocker encryption method and Cipher strength you set as default is only applied when you turn on BitLocker for a drive. Any changes you make will not affect a drive already encrypted by ...

In 1854, Sir Charles Wheatstone invented the cipher known as "Playfair," named for his friend Lyon Playfair, first Baron Playfair of St. Andrews, who popularized and promoted the cipher. Its ...