Google Inc. is making it tougher for computer hackers and other imposters to break into e-mail accounts and other password-protected services. An additional security measure introduced Monday will require typing a six-digit code after an accountholder's Google password is entered. The codes will be sent to people's mobile phones. The two-step process means it will take more than a password to get into an account, at least the first time that an attempted login is made from a particular computer. After logging in, users can ask Google to remember that their identity has been verified on that device and security codes won't be required to get into the account again. The extra protection initially will be offered to companies and government agencies subscribing to a Google service that provides e-mail and other office applications. People using Google's free Gmail service will have the option of making the security codes a part of their login process within the next few months
