Introduction

Julia Wrapper for the Relic Toolkit.

The goal is to facilitate a user-friendly, secure, and performant PBC lib for Julia.

Key Features

• Supports multiple Curves (BLS381 and BN254)
• Single-line (using ...) changes curve
• Supports both 32 and 64 bit machines
• Supports common operative systems (Linux, Mac, Windows)
• State-of-the art performance
• Production Ready (timing, side-channel resistance)

Quick Start

So lets implement the simplest possible BLS signature scheme in 10 lines of code!

The symbols (e.g. pk, H(m)) below were chosen to be consistent with this excellent blog.

using Pkg
Pkg.add(PackageSpec(url="https://github.com/blenessy/RelicToolkit.jl"))

Import the Curve functions you want to use (BLS381 and BN254 are currently supported):

using RelicToolkit.BLS381

Lets start by defining the following functions to remain consistent with Stepan's blog:

# a.k.a. hash to curve function
H(m) = curve_map(EP2, Vector{UInt8}(m))
# a.k.a. pairing function
e(P::EP, Q::EP2) = field_final_exp(curve_miller(P, Q))

Create a random private key:

pk = mod(rand(BN), curve_order(EP))

Generate a public key from the private key:

G = curve_gen(EP)
P = pk * G

Generate a public key from the private key:

P = pk * curve_gen(EP)

Sign a hashed message:

S = pk * H("foo")

Validate the signature:

@assert e(P, H("foo")) == e(G, S)

Performance

You can run the performance tests with:

make CURVE=BLS381 bench

Performance is state of the art (on par with C). You should get something like this on a 4-5 year old 2.2GHz Core i7:

...
[PP][field_final_exp]: 947.266 μs (alloc: 1, mem: 624 bytes, gc: 0.000 ns)
[PP][curve_miller]: 1.734 ms (alloc: 1, mem: 624 bytes, gc: 0.000 ns)
...

Since the pairing function is defined as field_final_exp(curve_miller(P, Q)) you can estimate its performance by adding these times together.

Configurations

Cofiguration is done through environment variables. The number of configuration possibilities should be limited for simplicity.

Key	Default	Description
RELIC_TOOLKIT_CURVE	(all curves are loaded)	Used for limiting, which curve is loaded (saves memory) at startup. Possible values are: BN254 and BLS381.

Contibutions

Contributions are welcome! If you are unsure where to chip in, please see the roadmap below.

Testing

Currect code coverage is 100% and the author would like to keep it that way.

Test	Purpose
UnitTests	Make sure the ccall are working and do not crash Julia.
SysTests	Protect complete features from breaking
PerfTests	Fair benchmarks for performance awareness

Fixes and minor features

Just create a PR (as usual in GitHub) and make sure that the code coverage stays at 100%.

High-level API changes and new Features

1. Please start by creating an issue and explain your use-case and goal.
2. Create a PR (as usual in GitHub) with the implementation and add a new SysTest to protect your use-case.

Roadmap

0.1.0: Provide smooth API for implementing BLS Signatures

• PoC finished (missing Windows)
• Add .travis.yml and improve README.md so that the community can help
• Add conversion from Integer
• Add syntactic sugar by overloading applicable operators (e.g. +, -, *, //, ^)
• Use BN(undef) and FP(undef) where safe to save some clock cycles
• Remove function name prefix from lib - it just make it harder to switch
• Make it possible to instantiate both libs in one session
• Implement zero and one functions
• Unit tests for EPX
• BLS Schema System Test and example in README.md
• README.md chapter about performance
• README.md chapter about configuration
• README.md chapter to contributors
• Tested on Windows
• Tested 32-bit Linux

0.2.0: Facilitate timing and side-channel resistance

• Fix TODOs in code
• Add gmp-sec libs for timing resistance.
• Use timing resistent FP, EP, and PP configs and functions.
• Add tests that measure time, CPU, Memory usage consistency over time.

0.x.0: PBC feature complete

• Julia 1.3.x and multi-thread support
• Implement all logical operators for BN, FP, and FPX
• Support all ARCH/OS combos that Julia and the Relic Toolkit has in common
• Support (signed) integers where BN is supported with FP and EP
• BN should extend Signed and should be automatically convertible/promotable to BigInt

1.0.0: Production Ready

• Academic/security audits (help needed)