Embodiments of the invention provide a table-free technique for detecting all temporal and spatial memory access errors in programs supporting general pointers. Embodiments of the invention provide such error checking using constant-time operations. Embodiments of the invention rely on fat pointers, whose size is contained within standard scalar sizes (up to two words) so that atomic hardware support for operations upon the pointers is obtained along with meaningful casts in-between pointers and other scalars. Optimized compilation of code becomes possible since the scalarized-for-free encoded pointers get register allocated and manipulated. Backward compatibility is enabled by the scalar pointer sizes, with automatic support provided for encoding and decoding of fat pointers in place for interaction with unprotected code.