Data security using bit transposition during memory accesses

Abstract

Apparatus and method for transferring data between a processing circuit and a memory. In some embodiments, a data storage device has a main non-volatile memory (NVM) configured to store user data from a host device. A controller circuit is configured to direct transfers of the user data between the NVM and the host device. The controller circuit has a programmable processor and a secure data transfer circuit. The secure data transfer circuit executes memory access operations to transfer user data and control values between the processor and a local memory. A memory access operation includes receiving bits of a multi-bit control value on a multi-line bus from the processor, and activating a programmable switching circuit to randomly interconnect different ones of the multi-line bus to transpose the bits in the control value.