Ad-hoc Threshold Multi-Signatures

Proof of Concept implementation. This crate is ongoing work, has not been audited, and API is by no means final. Do not use.

A Rust implementation of ATMS signatures

atms implements Ad-Hoc Threshold MultiSignatures (ATMS) implementation using Boldyreva multi signature scheme as described in Section 5.2 of the Proof-of-Stake Sidechains by Gazi, Kiayias and Zindros. Elliptic curve cryptography, and basic signature procedures are performed using the blst library by supranational which implements BLS signatures over curve BLS12-381.

The library exposes a C API for facilitating its usage with other languages.

ATMS C library Usage

Environment

Compiling and testing the C library requires a working installation of clang and gtest. To do so, one can check the documentation of your package-manager for system-dependent install instructions.

Note: For MacOS I made it work by adding -std=c++<VERSION> to the clang command below, after installing gtest as specified here. <VERSION> needs to be 11 or higher.

Compiling the library and header file

First, one needs to compile the library running: shell cargo build --release

Then, we need to build the header files using cbindgen. For this, first install cbindgen: shell cargo install cbindgen

and then build the header file by running the following command from the parent directory (nightly is required): shell rustup run nightly cbindgen ./ --config cbindgen.toml --crate atms --output target/include/atms.h

Running tests

For running rust tests, simply run (recommended use of --release, otherwise it takes a while):

shell cargo test --release

For the c-tests, we first build the test executable. First enter the c-tests folder, and then run:

sh clang -x c++ tests.c stms.c atms.c -g -o tests -L ../target/release -lmithril -lstdc++ -lgtest -lgtest_main

NOTE: Do not use g++, it does compile but leads to segfault when running the test.

To execute the tests:

``` sh ./tests [==========] Running 5 tests from 2 test suites. [----------] Global test environment set-up. [----------] 3 tests from atms [ RUN ] atms.produceAndVerifyAggregateSignature [ OK ] atms.produceAndVerifyAggregateSignature (27 ms) [ RUN ] atms.testingErrors [ OK ] atms.testingErrors (29 ms) [ RUN ] atms.serdeAtms [ OK ] atms.serdeAtms (14 ms) [----------] 3 tests from atms (71 ms total)

[----------] 2 tests from multisig [ RUN ] multisig.produceAndVerifyMultiSignature [ OK ] multisig.produceAndVerifyMultiSignature (2 ms) [ RUN ] multisig.serdeMultiSignature [ OK ] multisig.serdeMultiSignature (2 ms) [----------] 2 tests from multisig (4 ms total)

[----------] Global test environment tear-down [==========] 5 tests from 2 test suites ran. (76 ms total) [ PASSED ] 5 tests. ```