There are also security options for OS X Yosemite only.

35-Pass Erase – Writes over the data over 35 times.7-Pass Erase – Erases according to Department of Defense’s 5220-22M standards.Don’t Erase Data – Removes catalog, keeps data.Step 2: Select your external drive in the Disk Utility and then click Erase. Then the Disk Utility application will start as shown below. Step 1: First, Open the finder and get the Disk Utility by typing Disk Utility there and pressing enter. Look to the list below to see the wide range of selections The steps are to encrypt an external hard drive on macOS using FileVault. To securely erase your files from the thumb drive, press the button labeled “security options.” A variety of options will show, including even one that meets the Department of Defense’s 5220-22M standards. Passwords protect your USB, SSD & external drives with reliable security for your files & folders on USB Drives. Press “erase” on the bottom right of the screen.Look to the left side of the screen, clicking on the appropriate disk.

Password protect flash drive mac