The ransomware model is increasingly being adopted by cybercriminals who target mobile users, one of their latest creations being able to encrypt files stored on the SD memory cards of Android devices. A new threat dubbed Android/Simplock.A was identified by researchers from antivirus firm ESET over the weekend and while it's not the first ransomware program for Android, it is the first one seen by the company that holds files hostage by encrypting them.