rbcl

Ristretto group Python binding to libsodium

rbcl supports Python 3.7, 3.8 and 3.9.

from rbcl import *

x = crypto_core_ristretto255_random()
assert crypto_core_ristretto255_is_valid_point(x)

y = crypto_core_ristretto255_from_hash(b'\xF0'*64)
assert crypto_core_ristretto255_is_valid_point(y)

z1 = crypto_core_ristretto255_add(x, y)
z2 = crypto_core_ristretto255_add(y, x)
assert z1 == z2  # Assert that point addition commutes (in L)

s1 = crypto_core_ristretto255_scalar_random()
s2 = crypto_core_ristretto255_scalar_random()
w1 = crypto_scalarmult_ristretto255(s1, crypto_scalarmult_ristretto255(s2, x))
w2 = crypto_scalarmult_ristretto255(s2, crypto_scalarmult_ristretto255(s1, x))
assert w1 == w2  # Assert that point multiplication (by a scalar) is repeated addition (in L)

The following bindings are made available:

Constructors

crypto_core_ristretto255_random()
crypto_core_ristretto255_from_hash(h)
crypto_core_ristretto255_is_valid_point(p)

Scalar arithmetic

crypto_core_ristretto255_scalar_add(s1, s2)
crypto_core_ristretto255_scalar_sub(s1, s2)
crypto_core_ristretto255_scalar_mul(s1, s2)  # NOT scalar mulitplication of a point!
crypto_core_ristretto255_scalar_complement(s)
crypto_core_ristretto255_scalar_invert(s)
crypto_core_ristretto255_scalar_negate(s)
crypto_core_ristretto255_scalar_reduce(s)
crypto_core_ristretto255_scalar_random()

Point arithmetic

crypto_core_ristretto255_add(p, q)
crypto_core_ristretto255_sub(p, q)
crypto_scalarmult_ristretto255(p, s)
crypto_scalarmult_ristretto255_base(s)

Constants

crypto_scalarmult_ristretto255_bytes
crypto_scalarmult_ristretto255_scalarbytes
crypto_core_ristretto255_bytes
crypto_core_ristretto255_scalarbytes
crypto_core_ristretto255_hashbytes
crypto_core_ristretto255_nonreducedscalarbytes

Helpers

randombytes
randombytes_buf_deterministic

Manual installation

# Build as a wheel and install
python setup.py bdist_wheel
python -m pip install -f wheelhouse --no-index rbcl
python -m nose

Publishing (for Maintainers Only)

# Package source distribution
python setup.py sdist

# Run wheel-builder.yml and save/download artifacts locally, e.g. in ./dist
# Then, upload to PyPi
twine upload dist/rbcl-0.2.0*

Documentation

The documentation can be generated automatically from the source files using Sphinx:

cd docs
python -m pip install -r requirements.txt
sphinx-apidoc -f -E --templatedir=_templates -o _source .. ../setup.py ../rbcl/sodium_ffi.py && make html