Patent attributes
A portable storage device has a storage peripheral interface connecting to a computer. An encrypted data storage is available to the computer connected to the interface. The encrypted data storage includes a first part accessible after an authentication. A controller has a first operation mode performing encryption and decryption of data of the first part after the authentication of a first combined credential. The encryption and the decryption rely on a cipher key derived from a second combined credential. The first combined credential and the second combined credential are derived from at least a computer signature of the computer connected to the interface and a user credential of a user of the computer connected to the portable storage device.