bls12-381-unix

UNIX version of BLS12-381 primitives implementing the virtual package bls12-381 with blst backend
README

Encoding

Scalar

The scalar field is Fr = GF(0x73eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001), encoded on 32 bytes in little endian.

Groups

For G1, the base field is Fq: GF(0x1a0111ea397fe69a4b1ba7b6434bacd764774b84f38512bf6730d2a0f6b0f6241eabfffeb153ffffb9feffffffffaaab)
and E(Fq) := y^2 = x^3 + 4. An element of the base field can be encoded on 48 bytes (using only
381 bits, leaving 3 bits unused).

For G2, the base field is Fq2 := Fq[Z]/(X^2 + 1) and E(Fq2) := y^2 = x^3 + 4 (Z + 1). An element of the base field can be encoded on 2 * 48 bytes
representing each coefficient of the polynomial. 3 bits of each coefficient
encoding are unused.

The « uncompressed » form (x, y) of G1 and G2 is the concatenation of the elements x and y encoded in big endian.

The « compressed » form uses the first 3 most significant (and unused) bits of
the coordinate x.

  • the first most significant bit is always set to 1 to carry the information it
    is the compressed encoding of a point.

  • the second most significant bit is set to 1 if the element is the identity of the curve.

  • the third most significant bit is the sign of y. It is set to 1 if y is
    lexicographically larger than -y.

Install

# if you implement a library and you don't need an actual implementation
opam install bls12-381
# to target UNIX
opam install bls12-381-unix

By default, if the architecture supports ADX, bls12-381-unix with be compiled using ADX
opcodes (giving optimisations up to 20% for some arithmetic operations). If you
don't want to build using ADX, you can add the environment variable
BLST_PORTABLE and set it to any value.
For instance,

BLST_PORTABLE=y opam install bls12-381-unix

will instruct to build bls12-381-unix without ADX. This might be useful if you
build docker images on ADX machines but you need the image to be portable on
architecture not supporting ADX.

If the architecture does not support ADX, bls12-381-unix will be compiled without ADX opcodes.

Run tests

dune runtest

To get the coverage:

dune runtest --instrument-with bisect_ppx --force
bisect-ppx-report html

How to use in my project

If you are developing a library using bls12-381, you only need to add bls12-381 in the dependency list.
However, if you are writing a binary, three packages are relevant:

  • bls12-381-unix: to be used for UNIX

Run the benchmarks

Install core_bench:

opam install core_bench

See files listed in the directory benchmark and execute it with dune exec. For instance:

dune exec ./benchmark/bench_fr.exe

Documentation

opam install odoc
dune build @doc
Install
Sources
ocaml-bls12-381-2.0.1.tar.bz2
md5=493da0d50891299fb9577e6855653dca
sha512=994ac11cb76b0d83592cfb6b7a6d6f488a5d9c525d9bc1ccd81e797ee56c0e0b9a00d889118b4e5a01282d332d63d94d32ccbb6e063a28c1c53fecbea23dbef6
Dependencies
ff-pbt
>= "0.6.0" & < "0.7.0" & with-test
bisect_ppx
with-test & >= "2.5"
alcotest
with-test
bls12-381
= version
zarith
>= "1.10" & < "2.0"
dune
>= "2.8.4"
ocaml
>= "4.08"
Reverse Dependencies
tezos-base
>= "10.2" & < "13.0"
tezos-protocol-environment
>= "12.0" & < "13.0"