【Richard Rambuss, from Sacred Eroticism】

If you've just logged into your Yahoo email and Richard Rambuss, from Sacred Eroticismread an urgent security letter from the Yahoo team saying that your account has been compromised, you are one of the more than a billion users that have been hacked.

The massive data breach actually happened in August 2013 but was just revealed by the company.

It's separate to an incident from 2014 and is believed to affect names, email addresses, phone numbers, dates of birth, MD5-hashed passwords (a form of encryption now widely considered insecure) and security question answers, according to the company.

Yahoo said it is notifying potentially affected users and has taken steps to secure their accounts, including asking users to change their passwords.

You can follow these steps to secure your account:

1. Update your Yahoo accounts

If you haven't changed your username and password since August 2013 (the time when the hack occurred) it's time to do it immediately. Yahoo is advising all its users to update their credentials and security questions/answers. Both might have been compromised.

2. Change Yahoo passwords, security questions on other accounts

If you used your Yahoo passwords and security questions on multiple services, like social media or banking services, they could have been compromised. You need to urgently change them. This is an opportunity for you to learn to use different passwords on the service you use.

3. Use a password manager

Platforms like LastPass or 1Password can generate and store passwords and security answers for all of the accounts you have. These password managers only require users to have one master password, so they can make your life easier.

Yahoo advises to use Yahoo Account Key, the in-house authentication tool.

4. Don't trust emails asking for more information

Yahoo advises users to be cautious "of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information."

Similarly, users should avoid clicking on links or downloading attachments from suspicious emails or unknown email addresses.

5. Check your bank accounts

Yahoo also encourages users to review the online banking accounts for suspicious activity.

"Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information," it said.

Hackers who have gained private information might try to open a credit card in your name.