oprf module

Oblivious pseudo-random function (OPRF) protocol functionality implementations based on Curve25519 and the Ristretto group.

class oprf.oprf.data(bs: Optional[bytes] = None)

Bases: oblivious.ristretto.point

Wrapper class for a bytes-like object that corresponds to a piece of data that can be masked.

classmethod hash(argument: Union[str, bytes]) → oprf.oprf.data

Return data object constructed by hashing the supplied string or bytes-like object.

>>> data.hash('abc').hex()
'5a5dbd5c765abf60b2076133482c1ada189c319034ae0b933f4908b3b68d0225'
>>> data.hash(bytes([123])).hex()
'be6f2de25b6907d7e07e6a75424c6f4bbed103c2957b9fa9fbe4fd63dfa5575b'
>>> data.hash([1, 2, 3])
Traceback (most recent call last):
  ...
TypeError: can only hash a string or bytes-like object to a data object

classmethod from_base64(s: str) → oprf.oprf.data

Convert Base64 UTF-8 string representation of a data instance to a data object.

>>> d = data.hash('abc')
>>> data.from_base64(d.to_base64()) == d
True

static __new__(cls, bs: Optional[bytes] = None) → oprf.oprf.data

Return data object corresponding to the supplied bytes-like object. No checks are performed to confirm that the bytes-like object is a valid representation of a data object.

>>> d = data.hash('abc')
>>> bs = bytes(d)
>>> data(bs) == d
True

__truediv__(argument: oprf.oprf.mask) → oprf.oprf.data

Unmask this data object (assuming it has previously been masked with the supplied mask).

>>> d = data.hash('abc')
>>> m = mask.hash('abc')
>>> ((m(d)) / m) == d
True

to_base64() → str

Convert to Base64 UTF-8 string representation.

>>> d = data.hash('abc')
>>> d.to_base64()
'Wl29XHZav2CyB2EzSCwa2hicMZA0rguTP0kIs7aNAiU='

class oprf.oprf.mask(bs: Optional[bytes] = None)

Bases: oblivious.ristretto.scalar

Wrapper class for a bytes-like object that corresponds to a mask.

classmethod random() → oprf.oprf.mask

Return random non-zero mask object.

>>> m = mask.random()
>>> len(m) == 32 and oblivious.ristretto.scalar(m) == m
True

classmethod hash(argument: Union[str, bytes]) → oprf.oprf.mask

Return mask object constructed by hashing the supplied string or bytes-like object.

>>> mask.hash('abc').hex()
'ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f200150d'
>>> mask.hash(bytes([123])).hex()
'904ea0ec29650f3b2bcf481e3ea2553488030c865aae2decba8ce7016c4e380c'
>>> mask.hash([1, 2, 3])
Traceback (most recent call last):
  ...
TypeError: can only hash a string or bytes-like object to a mask object

classmethod from_base64(s: str) → oprf.oprf.mask

Convert Base64 UTF-8 string representation of a mask instance to a mask object.

>>> m = mask.hash('abc')
>>> mask.from_base64(m.to_base64()) == m
True

static __new__(cls, bs: Optional[bytes] = None) → oprf.oprf.mask

Return mask object corresponding to the supplied bytes-like object. No checks are performed to confirm that the bytes-like object is a valid representation of a mask object.

>>> m = mask()
>>> bs = bytes(m)
>>> mask(bs) == m
True

__invert__() → oprf.oprf.mask

Return the inverse of this mask instance.

>>> m = mask.hash('abc')
>>> (~m).hex()
'9d7c69e8dded15ba20544cee233db3148481e713863ddcf0dff9d56470ba8501'
>>> d = data.hash('abc')
>>> (~m)(m(d)) == d
True
>>> m((~m)(d)) == d
True

mask(argument: oprf.oprf.data) → oprf.oprf.data

Mask a data object with this mask and return the masked data object.

>>> d = data.hash('abc')
>>> m = mask.hash('abc')
>>> m.mask(d).hex()
'f47c8267b28ac5100e0e97b36190e16d4533b367262557a5aa7d97b811344d15'

__call__(argument: oprf.oprf.data) → oprf.oprf.data

Mask a data object with this mask and return the masked data object.

>>> d = data.hash('abc')
>>> m = mask.hash('abc')
>>> m(d).hex()
'f47c8267b28ac5100e0e97b36190e16d4533b367262557a5aa7d97b811344d15'

__mul__(argument: oprf.oprf.data) → oprf.oprf.data

Mask a data object with this mask and return the masked data object.

>>> d = data.hash('abc')
>>> m = mask.hash('abc')
>>> (m * d).hex()
'f47c8267b28ac5100e0e97b36190e16d4533b367262557a5aa7d97b811344d15'

unmask(argument: oprf.oprf.data) → oprf.oprf.data

Unmask a data object that has previously been masked with this mask (and return the original data object).

>>> d = data.hash('abc')
>>> m = mask.hash('abc')
>>> m.unmask(m(d)) == d
True

to_base64() → str

Convert to Base64 UTF-8 string representation.

>>> m = mask.hash('abc')
>>> m.to_base64()
'ungWv48Bz+pBQUDeXa4iI7ADYaOWF3qctBD/YfIAFQ0='