The U.S. government has demanded that major Internet companies divulge users' stored passwords, according to two industry sources familiar with these orders, which represent an escalation in surveillance techniques that has not previously been disclosed. If the government is able to determine a person's password, which is typically stored in encrypted form, the credential could be used to log in to an account to peruse confidential correspondence or even impersonate the user. Obtaining it also would aid in deciphering encrypted devices in situations where passwords are reused. Details here.