Flash Memory Data Protection via Read Address Verification

The patent segments data access control by dividing flash memory devices into authorized and unauthorized categories based on host identification. The controller implements separate access paths: one for authorized hosts that can access all data, and another for unauthorized hosts that are restricted to specific directories or files, thus maintaining data accessibility for legitimate users while preventing unauthorized copying.

The controller acts as an intermediary between the host and flash memory data. It intercepts access requests, verifies host authorization status, and selectively permits or blocks data access based on authorization. This intermediary function enables the system to maintain high data accessibility for authorized users while implementing security restrictions for unauthorized users without affecting overall system performance.

The system performs preliminary actions by recording the read addresses of authorized hosts during their normal operation. These addresses are stored in advance and used for comparison when determining authorization status. This preliminary recording simplifies the control mechanism because the authorization verification only requires comparing current read addresses against the pre-recorded authorized addresses, rather than implementing complex cryptographic verification for each access request.

The patent uses address copying as a simple verification mechanism. Instead of complex security protocols, it copies and stores the read addresses from authorized hosts, then compares future read addresses against these copied addresses. This copying-based approach maintains data security while minimizing device complexity, as it relies on simple address comparison rather than sophisticated authentication systems.