1. 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 based on the logical block address; 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.