Ransomware has become a huge issue in the past year. Ransomware was first detected on March 6, 2016, by Claud Xiao of Palo Alto Networks. The ransomware called KeRanger infected a BitTorrent product called Transmission.app. What ransomware does is encrypt your hard drive, then demands a "ransom" payment in the form of Bitcoin. After the payment is made, the creators of the ransomware claim to "give you a key that will be used for decryption.
What this means?
First, back up your data frequently. If you're using an external hard drive, then there is no reason to pay the ransom. Simply wipe your hard drive, and put your new information on. If you are looking for a way to block ransomware, there are a few free tools floating around out there.
I saw this video and found it fascinating. In May of 2017, a strain of ransomware called WanaCrypt0r, or more commonly known as "WannaCry" was released and a worldwide cyberattack began. In the following video, you can see each case as it happened.