Relocating Encrypted Partial Bitstreams by Advance Task Address Loading

The ability to relocate hardware tasks in FPGAs is an attractive task management technique, especially in reconfigurable operating systems. A method of relocation involves the modification of the location address of the task while it is being configured. However, the use of encryption to protect bitstreams requires that decryption is done on-chip before relocation. This usually results in a significant resource overhead, arising from the introduced decryption circuit. This paper presents Advance Task Address Loading (ATAL), a unique solution that involves loading the unencrypted task address ahead of the encrypted task's configuration frame data. We have developed a software named Splixbit, which processes the bitstream offline, and a corresponding hardware configuration controller that configures the bitstream on the FPGA. Our results confirmed the possibility of avoiding on-chip dedicated decryption circuit in relocating encrypted partial bitstreams.