Yahoo on Wednesday revealed that Net bandits stole data associated with 1 billion of its user accounts -- one of the largest data breaches in Internet history. The theft, which occurred in August 2013, is distinct from the theft disclosed earlier this fall, in which 500 million accounts were compromised, Yahoo CISO Bob Lord explained. Stolen information may include names, email addresses, telephone numbers, dates of birth, hashed passwords using MD5 encryption -- and in some cases, encrypted or unencrypted security questions and answers.