How to create an encrypted volume on an external drive or flash drive

Solution 1:

The best way to do this is via Disk Utility in the Application/Utilities folder. Review pictures for better understanding

Select the disk you want to encrypt Disk Utility

Choose the format method as in the picture, making sure you choose the option with Encryption Choose format

Next time you connect the disk, you will be asked to enter password. Here is what it looks like after you are done

You can create an encrypted volume using Disk Utility:

http://support.apple.com/kb/ht1578

Also, see here for information on FileVault:

Is File Vault 2 whole disk encryption or whole partition encryption?