OpenSK

This is an OpenSK fork that allows signing with a PQC Hybrid scheme. If you are looking for the original documentation, please check the develop branch of its GitHub page.

Hardware

You will need a Nordic nRF52840-DK development kit.

Installation

To install OpenSK,

1. follow the general setup steps,
2. then continue with the instructions for your specific hardware: Nordic nRF52840-DK

PQC Experiments

Modes

The Dilithium mode is set at compile time. If you want to perform experiments for different modes, you will need to recompile. The mode is a feature, defined in third_party/dilithium/Cargo.toml. By default, it is set to default = [ "dilithium5", "optimize_stack" ]. You can change the default mode by either changing the number 5 to 2 or 3. Or you remove the feature for stack optimizations, e.g. default = [ "dilithium2" ].

Note that some benchmarks will not run in all modes without stack optimizations. You can try to play with the stack size in these cases. As an example, stack painting for speed mode Dilithium2 works if you apply the following changes:

• APP_HEAP_SIZE = 16384 in deploy.py
• libtock_core::stack_size! {0x1A000} in examples/measure_stack.rs
• STACK_SIZE = 106496; in nrf52840_layout.ld
• Change the app break from 70 * 1024 to 104 * 1024 in patches/tock/07-app-break-fix.patch.

For your convenience, you can also simply try:

git apply increase_stack.patch

Compiler flags

To trade binary size for speed, you can play with [profile.release] in Cargo.toml. For example, try a different compiler optimization level:

opt-level = 3

Debug output

Only the CTAP commands tests are measured end to end on the host. All other experiments are measured on the embedded device itself and output over RTT. You can either use a client to print results by running the following commands in different terminals:

JLinkExe -device nrf52 -if swd -speed 1000 -autoconnect 1
JLinkRTTClient

Or you directly output all messages to a file:

JLinkRTTLogger -device NRF52840_XXAA -if swd -speed 1000 -RTTchannel 0

Perform Experiments

The paper contains the following experiments:

Crypto benchmarks

Deploy the crypto_bench example and read the debug output with one of the methods above:

./deploy.py --board=nrf52840dk_opensk --crypto_bench

CTAP benchmarks

To measure the speed of FIDO commands, run:

python benchmarks.py --runs=2000

Aggregate results will be printed, and the raw data is written to make_durations.txt and get_durations.txt.

Stack painting

Deploy the measure_stack example and read the debug output with one of the methods above:

./deploy.py --board=nrf52840dk_opensk --measure_stack

x86 benchmarks

You don't need your embedded hardware for those, run:

cd third_party/dilithium/
cargo bench --features std