Gemini is elastic proof system system, FFT-free, blazingly fast and space-conscious. This code is not meant for production use and has not been audited.

Documentation

Gemini's API can be accessed via:

cargo rustdoc --open

This include a detailed protocol description.

Features

Gemini can be compiled with the following feature flags:

• asm, to turn on the assembly backend within ark-ff;
• parallel, to turn on multi-threading. This requires the additional dependency rayon;
• std, to rely on the Rust Standard library;
• print-trace, to print additional information concerning the execution time of the sub-protocols. This feature must be enabled in order to monitor the execution time of the examples.

Performance

Micro-benchmarks for single components are done using criterion.rs. Benchmarks for the elastic and time-efficient provers can be run through the examples/. More specifically, to benchmark an instance of logarithmic size INSTANCE_LOGSIZE, run:

cargo run --features asm,print-trace,parallel --example snark -- -i <INSTANCE_LOGSIZE>

You monitor the memory used setting the environment variable RUST_LOG=debug. We tested so far ranges from 18 up to 35. It is also possible to run a purely-linear time prover with the additional option --time-prover.

Elasticity

Space footprint for the prover can be tweaked playing with the following constants:

• TENSOR_EXPANSION_LOG (set to 16) which sets the space budget for expanding the tensor products;
• MAX_MSM_BUFFER_LOG (set to 20) the size of the buffers over which Gemini performs multi-scalar multiplication;
• SPACE_TIME_THRESHOLD (set to 22) the threshold for converting the space-prover into the time-prover. It will run a separate thread measuring stack+heap consumption.

The so-called time_prover modules contain a full-speed implementation of the proving algorithm without constraints on space.