pymcl

A Python 3 wrapper for the mcl library. Currently support operations on BLS12-381 curve.

Installation

First, clone this repository using following command:

git clone https://github.com/Jemtaly/pymcl
cd pymcl

Then install the library:

For Debian-based systems (Debian, Ubuntu, Kali, etc.), you can simply install the library using the provided install.sh script.

For other platforms, to use pymcl, you need to build the mcl library from source first, follow the instructions here.

After building the mcl library, make sure you place the whole mcl library directory (which contains lib and include folders) in current directory, then, you can install the package using the following command:

pip install .

Basic Usage

Here is an example of how to use pymcl:

import pymcl

g1 = pymcl.g1 # generator of G1
g2 = pymcl.g2 # generator of G2
x1 = pymcl.Fr.random() # random element in Fr
x2 = pymcl.Fr.random() # random element in Fr

# check the correctness of the pairing
assert pymcl.pairing(g1 * x1, g2 * x2) == pymcl.pairing(g1, g2) ** (x1 * x2)

Other Operations

There are 4 types of elements in pymcl: Fr, G1, G2, and GT. You can perform operations on these elements as follows:

Fr Class

Fr(s: str) -> Fr

Create an element in Fr from a string, which is the decimal representation of the element. The library does not supply a constructor for Fr from an integer, you can convert an integer to a string and then use this constructor, the integer should be in the range of $[0, r)$, where $r$ is the order of the Fr group.

Fr.__str__(self: Fr) -> str

Convert the element to a string.

Fr.random() -> Fr

Return a random element in Fr.

Fr.__add__(self: Fr, other: Fr) -> Fr
Fr.__sub__(self: Fr, other: Fr) -> Fr
Fr.__neg__(self: Fr) -> Fr
Fr.__mul__(self: Fr, other: Fr) -> Fr
Fr.__truediv__(self: Fr, other: Fr) -> Fr
Fr.__invert__(self: Fr) -> Fr

Perform addition, subtraction, negation, multiplication, division, and inversion on the element.

Fr.__eq__(self: Fr, other: Fr) -> bool
Fr.__ne__(self: Fr, other: Fr) -> bool
Fr.isZero(self: Fr) -> bool
Fr.isOne(self: Fr) -> bool

Check the equality and inequality of the element, and check if the element is the additive identity or the multiplicative identity.

Fr.__hash__(self: Fr) -> int

Return the hash value of the element.

Fr.serialize(self: Fr) -> bytes
Fr.deserialize(b: bytes) -> Fr

Serialize and deserialize the element.

G1 Class

G1(s: str) -> G1

Create an element in G1 from its string representation.

G1.__str__(self: G1) -> str

Convert the element to a string. (check the API of mcl for the format of the string representation)

G1.hash(b: bytes) -> G1

Hash a byte array to an element in G1. (check here)

G1.__add__(self: G1, other: G1) -> G1
G1.__sub__(self: G1, other: G1) -> G1
G1.__neg__(self: G1) -> G1
G1.__mul__(self: G1, other: Fr) -> G1

Perform addition, subtraction, negation, and multiplication on the element. Note that for the multiplication of G1 and Fr, the Fr element should be on the right-hand side.

G1.__eq__(self: G1, other: G1) -> bool
G1.__ne__(self: G1, other: G1) -> bool
G1.isZero(self: G1) -> bool

Check the equality and inequality of the element, and check if the element is the additive identity.

G1.__hash__(self: G1) -> int

Return the hash value of the element.

G1.serialize(self: G1) -> bytes
G1.deserialize(b: bytes) -> G1

Serialize and deserialize the element (in compressed form).

G2 Class

The G2 class has the same methods as the G1 class.

GT Class

GT(s: str) -> GT

Create an element in GT from its string representation.

GT.__str__(self: GT) -> str

Convert the element to a string.

GT.__mul__(self: GT, other: GT) -> GT
GT.__truediv__(self: GT, other: GT) -> GT
GT.__invert__(self: GT) -> GT
GT.__pow__(self: GT, other: Fr) -> GT

Perform multiplication, division, inversion, and exponentiation on the element.

GT.__eq__(self: GT, other: GT) -> bool
GT.__ne__(self: GT, other: GT) -> bool
GT.isZero(self: GT) -> bool
GT.isOne(self: GT) -> bool

Check the equality and inequality of the element, and check if the element is the additive identity or the multiplicative identity.

GT.__hash__(self: GT) -> int

Return the hash value of the element.

GT.serialize(self: GT) -> bytes
GT.deserialize(b: bytes) -> GT

Serialize and deserialize the element.

Other Function and Constants

pairing(a: G1, b: G2) -> GT

Compute the pairing of two elements in G1 and G2, note that the first argument should be in G1 and the second argument should be in G2.

g1: G1
g2: G2

The generator of G1 and G2.

r: int

The order of the G1, G2, Fr, and GT groups.