distributed_keygen.paillier_shared_key module

Paillier secret key that is shared amongst several parties.

class distributed_keygen.paillier_shared_key.PaillierSharedKey(n, t, player_id, share, theta)[source]

Bases: SecretKey

Class containing relevant attributes and methods of a shared paillier key.

class SerializedPaillierSharedKey[source]

Bases: TypedDict

Serialized PaillierSharedKey for e.g. storing the key to disk.

n: int
player_id: int
share: IntegerShares
t: int
theta: int
__eq__(other)[source]

Compare this PaillierSharedKey with another to determine (in)equality.

Parameters:

other (object) – Object to compare this PaillierSharedKey with.

Raises:

TypeError – When other object is not a PaillierSharedKey.

Return type:

bool

Returns:

Boolean value representing (in)equality of both objects.

__init__(n, t, player_id, share, theta)[source]

Initializes a Paillier shared key.

Parameters:

  • n (int) – modulus of the DistributedPaillier scheme this secret key belongs to

  • t (int) – corruption_threshold of the secret sharing

  • player_id (int) – the index of the player to whom the key belongs

  • share (IntegerShares) – secret sharing of the exponent used during decryption

  • theta (int) – Value used in the computation of a full decryption after partial decryptions have been obtained. We refer to the paper for more details

__str__()[source]

Utility function to represent the local share of the private key as a string.

Return type:

str

Returns:

String representation of this private key part.

decrypt(partial_dict)[source]

Function that uses partial decryptions of other parties to reconstruct a full decryption of the initial ciphertext.

Parameters:

partial_dict (dict[int, int]) – dictionary containing the partial decryptions of each party

Raises:

ValueError – Either in case not enough shares are known in order to decrypt. Or when the combined decryption minus one is not divisible by $N$. This last case is most likely caused by the fact the ciphertext that is being decrypted, differs between parties.

Return type:

int

Returns:

full decryption

static deserialize(obj, **_kwargs)[source]

Deserialization function for public keys, which will be passed to the communication module.

Parameters:

  • obj (SerializedPaillierSharedKey) – serialized version of a PaillierSharedKey.

  • **_kwargs (Any) – optional extra keyword arguments

Raises:

SerializationError – When communication library is not installed.

Return type:

PaillierSharedKey

Returns:

Deserialized PaillierSharedKey from the given dict.

partial_decrypt(ciphertext)[source]

Function that does local computations to get a partial decryption of a ciphertext.

Parameters:

ciphertext (PaillierCiphertext) – ciphertext to be partially decrypted

Raises:

  • TypeError – If the given ciphertext is not of type PaillierCiphertext.

  • ValueError – If the ciphertext is encrypted against a different key.

Return type:

int

Returns:

partial decryption of ciphertext

serialize(**_kwargs)[source]

Serialization function for public keys, which will be passed to the communication module.

Parameters:

**_kwargs (Any) – optional extra keyword arguments

Raises:

SerializationError – When communication library is not installed.

Return type:

SerializedPaillierSharedKey

Returns:

serialized version of this PaillierSharedKey.