Security researchers took a look at some popular self-encrypting consumer HDDs from Western Digital and found they're riddled with security issues that make it easy for someone to retrieve your data, sometimes even without having to crack your password:
The paper, titled got HW crypto? On the (in)security of a Self-Encrypting Drive series, recited a litany of weaknesses in the multiple versions of the My Passport and My Book brands of external hard drives. The flaws make it possible for people who steal a vulnerable drive to decrypt its contents, even when they're locked down with a long, randomly generated password. The devices are designed to self-encrypt all stored data, a feature that saves users the time and expense of using full-disk encryption software.
"After researching the inner workings of some of the numerous models in the My Passport external hard drive series, several serious security vulnerabilities have been discovered, affecting both authentication and confidentiality of user data," the researchers wrote. "We developed several different attacks to recover user data from these password protected and fully encrypted external hard disks."
The full 36-page report can be found over here. Users wishing to securely encrypt a HDD are recommended to opt for software from provides with a longer track record like Symantec, which acquired PGP's Full Disk Encryption.