1 /* 2 * Copyright 2019 Google LLC. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * https://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef PRIVATE_JOIN_AND_COMPUTE_PRIVATE_INTERSECTION_SUM_SERVER_IMPL_H_ 17 #define PRIVATE_JOIN_AND_COMPUTE_PRIVATE_INTERSECTION_SUM_SERVER_IMPL_H_ 18 19 #include <memory> 20 #include <string> 21 #include <utility> 22 #include <vector> 23 24 #include "private_join_and_compute/crypto/context.h" 25 #include "private_join_and_compute/crypto/ec_commutative_cipher.h" 26 #include "private_join_and_compute/crypto/paillier.h" 27 #include "private_join_and_compute/match.pb.h" 28 #include "private_join_and_compute/message_sink.h" 29 #include "private_join_and_compute/private_intersection_sum.pb.h" 30 #include "private_join_and_compute/private_join_and_compute.pb.h" 31 #include "private_join_and_compute/protocol_server.h" 32 #include "private_join_and_compute/util/status.inc" 33 34 namespace private_join_and_compute { 35 36 // The "server side" of the intersection-sum protocol. This represents the 37 // party that will receive the size of the intersection as its output. The 38 // values that will be summed are supplied by the other party; this party will 39 // only supply set elements as its inputs. 40 class PrivateIntersectionSumProtocolServerImpl : public ProtocolServer { 41 public: PrivateIntersectionSumProtocolServerImpl(::private_join_and_compute::Context * ctx,std::vector<std::string> inputs)42 PrivateIntersectionSumProtocolServerImpl( 43 ::private_join_and_compute::Context* ctx, std::vector<std::string> inputs) 44 : ctx_(ctx), inputs_(std::move(inputs)) {} 45 46 ~PrivateIntersectionSumProtocolServerImpl() override = default; 47 48 // Executes the next Server round and creates a response. 49 // 50 // If the ClientMessage is StartProtocol, a ServerRoundOne will be sent to the 51 // message sink, containing the encrypted server identifiers. 52 // 53 // If the ClientMessage is ClientRoundOne, a ServerRoundTwo will be sent to 54 // the message sink, containing the intersection size, and encrypted 55 // intersection-sum. 56 // 57 // Fails with InvalidArgument if the message is not a 58 // PrivateIntersectionSumClientMessage of the expected round, or if the 59 // message is otherwise not as expected. Forwards all other failures 60 // encountered. 61 Status Handle(const ClientMessage& request, 62 MessageSink<ServerMessage>* server_message_sink) override; 63 protocol_finished()64 bool protocol_finished() override { return protocol_finished_; } 65 66 // Utility function, used for testing. GetECCipher()67 ECCommutativeCipher* GetECCipher() { return ec_cipher_.get(); } 68 69 private: 70 // Encrypts the server's identifiers. 71 StatusOr<PrivateIntersectionSumServerMessage::ServerRoundOne> EncryptSet(); 72 73 // Computes the intersection size and encrypted intersection_sum. 74 StatusOr<PrivateIntersectionSumServerMessage::ServerRoundTwo> 75 ComputeIntersection(const PrivateIntersectionSumClientMessage::ClientRoundOne& 76 client_message); 77 78 Context* ctx_; // not owned 79 std::unique_ptr<ECCommutativeCipher> ec_cipher_; 80 81 // inputs_ will first contain the plaintext server identifiers, and later 82 // contain the encrypted server identifiers. 83 std::vector<std::string> inputs_; 84 bool protocol_finished_ = false; 85 }; 86 87 } // namespace private_join_and_compute 88 89 #endif // PRIVATE_JOIN_AND_COMPUTE_PRIVATE_INTERSECTION_SUM_SERVER_IMPL_H_ 90