Buslink CipherShield 4TB 256-bit Encrypted External Hard Drive with Bilateral Access Mode safeguards and protects classified information when they are too important to be left in the hand of one individual. To gain access to the drive, authentication will be based on two unique Cipher Keys. Unlike its counterpart with collateral access method, this model requires both keys to be plugged in all the time while working with the drive. It is like getting a safe deposit box that takes two keys to open. CipherShield Encrypted Drive with Bilateral Access Mode is suitable for group setting where more than one individual are working on highly confidential projects. i.e. blueprints for company's next new products, top secret programs, highly confidential legal cases, sensitive customer records and financial information.