I do not need to get into detail about the high profile data breaches of recent times, you are sure to know of most of them. Maylaysia just had a breach of 46 million mobile phone numbers and some have been found for sale or free on the dark web.
So how do you find out if your data is out there in the dark web?
One way is: Have I been pwned? https://haveibeenpwned.com/
Just enter your data, for instance your email and it will check it's database to see if your email has been found on any websites serving up breach data.