BLS Signature Scheme over BLS12-381 pairing-friendly curve

This library implements:

• The BLS signature scheme (Boneh-Lynn-Shacham)
• over the BLS12-381 (Barreto-Lynn-Scott) pairing-friendly curve

Cipher suite ID: BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_POP_

Installation

You can install the developement version of the library through nimble with the following command

nimble install https://github.com/status-im/nim-blscurve

Implementation stability

This repo follows Ethereum 2.0 requirements.

Besides the standardization work described below, no changes are planned upstream for the foreseeable future.

Standardization

Currently (Jun 2019) a cross-blockchain working group is working to standardize BLS signatures for the following blockchains:

• Algorand
• Chia Network
• Dfinity
• Ethereum 2.0
• Filecoin
• Zcash Sapling

Signature scheme

• IETF draft submission v2: https://tools.ietf.org/html/draft-boneh-bls-signature-02
• Repo for collaboration on the draft: https://github.com/cfrg/draft-irtf-cfrg-bls-signature

Hashing to curve

• https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-09
• https://github.com/cfrg/draft-irtf-cfrg-hash-to-curve

Note: the implementation was done following Hash-to-curve v7 v9 and v7 are protocol compatible but have cosmetic changes (naming variables, precomputing constants, ...)

Curve implementation

• https://tools.ietf.org/html/draft-irtf-cfrg-pairing-friendly-curves-00

Backend

This library uses:

• SupraNational BLST on all platforms.

BLST uses SSSE3 by default, if supported on the host. To disable that, when building binaries destined for older CPUs, pass -d:BLSTuseSSSE3=0 to the Nim compiler.

Executing the test suite

We recommend working within the nimbus build environment described here: https://github.com/status-im/nimbus-eth2

To execute the test suite, just navigate to the root of this repo and execute:

nimble test

Please note that within the nimbus build environment, the repository will be located in nimbus-eth2/vendor/nim-blscurve.

Executing the fuzzing tests

Before you start, please make sure that the regular test suite executes successfully (see the instructions above). To start a particular fuzzing test, navigate to the root of this repo and execute:

nim tests/fuzzing/run_fuzzing_test.nims <test-name>

You can specify the fuzzing engine being used by passing an additional --fuzzer parameter. The currently supported engines are libFuzzer (used by default) and afl.

All fuzzing tests are located in tests/fuzzing and use the following naming convention:

fuzz_<test-name>.nim

License

Licensed and distributed under either of

• MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT
• Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)

at your option. These files may not be copied, modified, or distributed except according to those terms.

Dependencies

• SupraNational BLST is distributed under the Apache License, Version 2.0