Logical-to-physical address translation for a removable data storage device

A portable storage device comprising:

• memory configured to store encrypted data at physical memory addresses with different physical block numbers within the portable storage device, the memory having a page organization wherein sector data are mapped to the physical memory addresses and extra data are mapped adjacent the sector data;
• a lookup table for mapping the physical memory addresses to logical memory addresses, the lookup table assigning different decryption keys to different logical block address ranges corresponding to the different physical block numbers;
• a processor coupled with the memory, the processor configured to decrypt the encrypted data using one of different decryption keys;
• and
• an interface coupled with the processor, the interface configured to receive the logical memory addresses and communicate the decrypted data to a host device.

A method for operating a removable memory storage device coupled to a host computer, the method comprising:

• storing encrypted data at physical memory addresses within memory of the removable storage device;
• receiving logical addresses from the host computer;
• determining the physical memory addresses corresponding to the logical memory addresses via a lookup table stored on the removable storage device;
• decrypting the encrypted data using a decryption key corresponding to the encrypted data stored at the physical memory addresses, wherein the lookup table assigns different decryption keys to encrypted data stored at different physical memory addresses in the memory of the removable storage device;
• and
• communicating the decrypted data from the removable storage device to the host computer.