Bit-flipping memory controller to prevent sram data remanence

Abstract

A memory is organized into blocks. In a bit-flipping operation, a memory block is read, the read bit data values are inverted, and the inverted data is written back to the memory block. Inverted memory blocks are tracked by setting a flag bit in the memory block, or by storing a pointer to a memory block. In a read operation, a memory block is read and, if the tracking method indicates the memory block is inverted, the read data values are reverted before being returned. In a write operation, a memory block is read and, if the tracking method indicates the memory block is inverted, the write data values are inverted before being written. Inversion of data values and tracking of inverted memory blocks may be performed by a specialized memory controller or by a processor executing secure memory code. Data remanence is thus prevented in the memory.