About Keccak - Shuang's Crypto Notes

Table of Contents

Performance metrics

When people talking about the performance of the hash functions in SHA-3 family, what are the key performance metrics they are using?

Throughput refers to the speed at which the hash function can process data. In a hardware context, it’s typically measured in terms of the number of hashes computed per second, or how much data can be processed in a given time period.
Common units:
- Hashes per second (e.g., MHashes/s, GHashes/s).
- Bits per second (e.g., Gbps, Gb/s).
Example: A high-throughput SHA-3 implementation might process 1 billion hashes per second (1 GHash/s).

Area refers to the physical space or resources that an ASIC implementation of a hash function consumes. In ASIC terms, this is usually measured in gate equivalents (GE), which is a unit of area that expresses the number of basic logic gates required to implement the design.
Gate equivalents (GE) provide an indication of the hardware cost or the size of the circuit.
- Low area means the circuit occupies less space, which can be desirable for power-efficient or cost-effective implementations.
Example: You might see an implementation that requires 50 kGE (50,000 gate equivalents) to implement a SHA-3 hash function.
Sometimes, the area is expressed as area per hash, meaning how much area is required to compute one hash or a certain amount of data (e.g., kGE per 256-bit hash).

Energy refers to the amount of power required by the hardware to compute the hash function, and it’s usually measured in terms of power consumption over time.

VT (VLSI Technology): Refers to the technology used to fabricate the chip, including the process node (e.g., 14nm, 7nm) and how efficiently the design uses the silicon. This is related to both area and power consumption.
ETHZ and GMU: These refer to research institutions or universities that may be involved in the design, testing, and benchmarking of these implementations. ETHZ refers to ETH Zurich, and GMU likely refers to George Mason University.

When discussing ASIC implementations of hash functions (such as Keccak/SHA-3), performance is generally evaluated with respect to throughput, energy efficiency, and area efficiency because ASICs are designed to perform a specific task with optimal speed and power consumption.
Performance comparisons often involve measurements like area in kGE, throughput (MHashes/s or GHashes/s), and energy per hash (nJ/hash).

Keccak circuit introduction in this blog by huwenqing