SHA-3 Secure Hash Function Core

The SHA-3 is a high-throughput, area-efficient hardware accelerator for the SHA-3 cryptographic hashing functions, compliant to NIST’s FIPS 180-4 and FIPS 202 standards.

The accelerator core requires no assistance from a host processor and uses standard AMBA® AXI4-Stream interfaces for input and output data. An AXI4-Stream to AXI4 Memory Mapped bridge, with or without DMA capabilities, can be used with the core and is separately available from CAST. A single instance of the core implements all fixed-length and extendable-output hash functions. The cryptographic function, the length of the extendable output function (up to 2GB) is chosen at run time via AXI4-Stream side-band signals and can be different for every input message.

The SHA-3 core is also highly configurable at synthesis time, to ease integration in systems with different requirements. The data-bus width of the input and output interfaces is configurable at synthesis time. The number of SHA-3 permutation rounds per clock cycle is also configurable at synthesis time, allowing users to trade throughput for silicon resources. Under its minimum configuration of one permutation per cycle, the core processes 50 bits per cycle depending on the hashing function. Its throughput can scale by implementing 2, 3, or 4 permutations per cycle respectively, enabling throughputs in excess of 100Gbps in modern ASIC technologies.

The core is designed for ease of use and integration and adheres to industry-best coding and verification practices. Technology mapping, and timing closure are trouble-free, as the core contains no multi-cycle or false paths, and uses only ris-ing-edge-triggered D-type flip-flops, no tri-states, and a single-clock/reset domain.