package private_join_and_compute

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gRPC interface for Private Join and Compute.

• rpc Handle (ClientMessage, ServerMessage)

  private_join_and_compute.proto:39

  Handles a single protocol round.

  message ClientMessage

  private_join_and_compute.proto:22

  • oneof client_message_oneof

    • PrivateIntersectionSumClientMessage private_intersection_sum_client_message = 1

  message ServerMessage

  private_join_and_compute.proto:29

  • oneof server_message_oneof

    • PrivateIntersectionSumServerMessage private_intersection_sum_server_message = 1

• int32 curve_id = 1

  Named curve id

• bytes key = 2

Ciphertext of ElGamal encryption scheme. For ElGamal over integers, all the fields are serialized BigNums; for ElGamal over an Elliptic Curve, all the fields are serialized ECPoints. For public key (g, y), message m, and randomness r: u = g^r; e = m * y^r. In exponential ElGamal encryption scheme, for public key (g, y), small message m, and randomness r: u = g^r; e = g^m * y^r.

• bytes u = 1

• bytes e = 2

Public key for ElGamal encryption scheme. For ElGamal over integers, all the fields are serialized BigNums; for ElGamal over an Elliptic Curve, g and y are serialized ECPoints, p is not set. g is the generator of a cyclic group. y = g^x for a random x, where x is the secret key. To encrypt a message m: u = g^r for a random r; e = m * y^r; Ciphertext = (u, e). To encrypt a small message m in exponential ElGamal encryption scheme: u = g^r for a random r; e = g^m * y^r; Ciphertext = (u, e). Note: The exponential ElGamal encryption scheme is an additively homomorphic encryption scheme, and it only works for small messages.

• bytes p = 1

  modulus of the integer group

• bytes g = 2

• bytes y = 3

Secret key (or secret key share) for ElGamal encryption scheme. x is a serialized BigNum. To decrypt a ciphertext (u, e): m = e * (u^x)^{-1}. To decrypt a ciphertext (u, e) in exponential ElGamal encryption scheme: m = log_g (e * (u^x)^{-1}). In a 2-out-of-2 threshold ElGamal encryption scheme, for secret key shares x_1 and x_2, the ElGamal secret key is x = x_1 + x_2, satisfying y = g^x for public key (g, y). To jointly decrypt a ciphertext (u, e): Each party computes (u^{x_i})^{-1}; m = e * (u^{x_1})^{-1} * (u^{x_2})^{-1}, or m = log_g (e * (u^{x_1})^{-1} * (u^{x_2})^{-1}) in exponential ElGamal.

• bytes x = 1

Holds an encrypted value and possibly encrypted associated data.

Used in: EncryptedSet

• bytes element = 1

• bytes associated_data = 2

Holds a set of encrypted values.

Used in: PrivateIntersectionSumClientMessage.ClientRoundOne, PrivateIntersectionSumServerMessage.ServerRoundOne

• repeated EncryptedElement elements = 1

• bytes p = 1

  p and q contain serialized BigNums, such that the Paillier modulus n=pq.

• bytes q = 2

• int32 s = 3

  Contains the Damgard-Jurik exponent corresponding to this key. The Paillier modulus will be n^(s+1), and the message space will be n^s.

Holds a Paillier Public Key.

• bytes n = 1

  Contains a serialized BigNum encoding the Paillier modulus n.

• int32 s = 2

  Contains the Damgard-Jurik exponent corresponding to this key. The Paillier modulus will be n^(s+1), and the message space will be n^s.

Used in: ClientMessage

• oneof message_content

  • PrivateIntersectionSumClientMessage.StartProtocolRequest start_protocol_request = 1

  • PrivateIntersectionSumClientMessage.ClientRoundOne client_round_one = 2

Message containing the client's set encrypted under the client's keys, and the server's set re-encrypted with the client's key, and shuffled.

Used in: PrivateIntersectionSumClientMessage

• bytes public_key = 1

• optional EncryptedSet encrypted_set = 2

• optional EncryptedSet reencrypted_set = 3

For initiating the protocol.

Used in: PrivateIntersectionSumClientMessage

(message has no fields)

Used in: ServerMessage

• oneof message_content

  • PrivateIntersectionSumServerMessage.ServerRoundOne server_round_one = 1

  • PrivateIntersectionSumServerMessage.ServerRoundTwo server_round_two = 2

Used in: PrivateIntersectionSumServerMessage

• optional EncryptedSet encrypted_set = 1

Used in: PrivateIntersectionSumServerMessage

• int64 intersection_size = 1

• bytes encrypted_sum = 2