Second stage pir (#57)

* manager: fix location of commas in test funcs * evaluator: add ptx decomposition mult * evaluator:add test for ptx embedding * evaluator:add ntt transform for EmbeddedCiphertext * server.cpp: minor change for debug mode
elkanatovey · Dec 11, 2022 · b75a7d2 · b75a7d2
1 parent 2f516d0
commit b75a7d2
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Showing 7 changed files with 96 additions and 15 deletions.
diff --git a/src/math_utils/evaluator_wrapper.cpp b/src/math_utils/evaluator_wrapper.cpp
@@ -235,23 +235,31 @@ namespace math_utils {
         }
     }
 
-    void EvaluatorWrapper::get_ptx_embedding(const seal::Ciphertext &ctx, const seal::RelinKeys& relin_keys, std::vector<seal::Plaintext>  &ptx_decomposition) const {
-        seal::Ciphertext ctx_copy;
-        evaluator->relinearize(ctx, relin_keys, ctx_copy);
-        evaluator->mod_switch_to_inplace(ctx_copy, context.last_parms_id());
+    void EvaluatorWrapper::get_ptx_embedding(const seal::Ciphertext &ctx, EmbeddedCiphertext  &ptx_decomposition) const {
 
-        ptx_decomposition = std::move(decompose_to_plaintexts(context.last_context_data()->parms(), ctx_copy));
+        ptx_decomposition =  std::move(decompose_to_plaintexts(context.last_context_data()->parms(), ctx));
 
-        for(auto & ptx : ptx_decomposition){
-            evaluator->transform_to_ntt_inplace(ptx, context.first_parms_id());
-        }
 
     }
 
     void EvaluatorWrapper::compose_to_ctx(const std::vector<seal::Plaintext>  &ptx_decomposition, seal::Ciphertext &decoded) const {
         seal::Ciphertext ctx_copy(context, context.last_parms_id());
         compose_to_ciphertext( context.last_context_data()->parms(), ptx_decomposition, ctx_copy);
-        decoded = ctx_copy;
+        decoded = std::move(ctx_copy);
+    }
+
+
+    void EvaluatorWrapper::mult_with_ptx_decomposition(const EmbeddedCiphertext &ptx_decomposition, const seal::Ciphertext &ctx, EncryptedEmbeddedCiphertext  &result) const {
+#ifdef DISTRIBICOM_DEBUG
+        assert(ptx_decomposition[0].is_ntt_form());
+        assert(ctx.is_ntt_form());
+#endif
+
+        std::vector<seal::Ciphertext> result_copy(ptx_decomposition.size());
+        for(auto i=0; i<ptx_decomposition.size(); i++){
+            evaluator->multiply_plain(ctx, ptx_decomposition[i], result_copy[i]);
+        }
+        result = std::move(result_copy);
     }
 
     void EvaluatorWrapper::scalar_multiply(std::uint64_t scalar, const seal::Ciphertext &right,
@@ -268,4 +276,25 @@ namespace math_utils {
     }
 
 
+    void EvaluatorWrapper::transform_to_ntt_inplace(EmbeddedCiphertext  &encoded) const {
+        for(auto & ptx_piece : encoded) {
+            evaluator->transform_to_ntt_inplace(ptx_piece, context.first_parms_id());
+        }
+    }
+
+
+    void EvaluatorWrapper::add_embedded_ctxs(const EncryptedEmbeddedCiphertext &ctx_decomposition1, const EncryptedEmbeddedCiphertext &ctx_decomposition2, EncryptedEmbeddedCiphertext  &result) const {
+#ifdef DISTRIBICOM_DEBUG
+        assert(ctx_decomposition1[0].is_ntt_form());
+        assert(ctx_decomposition2[0].is_ntt_form());
+        assert(ctx_decomposition1.size()==ctx_decomposition2.size());
+#endif
+
+        EncryptedEmbeddedCiphertext result_copy(ctx_decomposition1.size());
+        for(auto i=0; i<ctx_decomposition1.size(); i++){
+            evaluator->add(ctx_decomposition1[i], ctx_decomposition2[i], result_copy[i]);
+        }
+        result = std::move(result_copy);
+    }
+
 }
diff --git a/src/math_utils/evaluator_wrapper.hpp b/src/math_utils/evaluator_wrapper.hpp
@@ -12,6 +12,14 @@ namespace math_utils {
      */
     typedef std::vector<seal::Plaintext> SplitPlaintextNTTForm;
 
+
+    /***
+     * EmbeddedCiphertext represents a ciphertext that was embedded into plaintexts
+     */
+    typedef std::vector<seal::Plaintext> EmbeddedCiphertext;
+
+    typedef std::vector<seal::Ciphertext> EncryptedEmbeddedCiphertext;
+
 /***
  * This class wraps and modifies the behaviour of seal::Evaluator to add wanted multiplication for distribicom.
  */
@@ -103,10 +111,20 @@ namespace math_utils {
         void trivial_ciphertext(const seal::Plaintext &ptx, seal::Ciphertext &result) const;
 
         /***
-         * writes ptx embedding of ctx to ptx_decomposition after relinearizing ctx and putting switching to last modulus
+         * writes ptx embedding of ctx to ptx_decompositio
          */
-        void get_ptx_embedding(const seal::Ciphertext &ctx, const seal::RelinKeys& relin_keys, std::vector<seal::Plaintext>  &ptx_decomposition) const;
+        void get_ptx_embedding(const seal::Ciphertext &ctx, EmbeddedCiphertext  &ptx_decomposition) const;
 
         void compose_to_ctx(const std::vector<seal::Plaintext> &ptx_decomposition, seal::Ciphertext &decoded) const;
+
+        void
+        mult_with_ptx_decomposition(const EmbeddedCiphertext &ptx_decomposition, const seal::Ciphertext &ctx,
+                                    std::vector<seal::Ciphertext> &result) const;
+
+        void add_embedded_ctxs(const EncryptedEmbeddedCiphertext &ctx_decomposition1,
+                               const EncryptedEmbeddedCiphertext &ctx_decomposition2,
+                               EncryptedEmbeddedCiphertext &result) const;
+
+        void transform_to_ntt_inplace(EmbeddedCiphertext &encoded) const;
     };
 }
diff --git a/src/math_utils/matrix_operations.cpp b/src/math_utils/matrix_operations.cpp
@@ -144,6 +144,13 @@ namespace math_utils {
         }
     }
 
+    void MatrixOperations::to_ntt(std::vector<seal::Plaintext> &m) const {
+        std::for_each(std::execution::par_unseq, m.begin(), m.end(), [this](seal::Plaintext &ptx) {
+            w_evaluator->evaluator->transform_to_ntt_inplace(ptx, this->w_evaluator->context.first_parms_id());
+        });
+    }
+
+
     void MatrixOperations::to_ntt(std::vector<seal::Ciphertext> &m) const {
         std::for_each(std::execution::par_unseq, m.begin(), m.end(), [this](seal::Ciphertext &ctx) {
             w_evaluator->evaluator->transform_to_ntt_inplace(ctx);

diff --git a/src/math_utils/matrix_operations.hpp b/src/math_utils/matrix_operations.hpp
@@ -192,6 +192,7 @@ namespace math_utils {
                        const matrix<seal::Ciphertext> &b,
                        matrix<seal::Ciphertext> &result) const;
 
+        void to_ntt(std::vector<seal::Plaintext> &m) const;
     };
 
 }

diff --git a/src/services/manager.cpp b/src/services/manager.cpp
@@ -81,9 +81,9 @@ namespace services {
     std::shared_ptr<WorkDistributionLedger>
     Manager::distribute_work(const math_utils::matrix<seal::Plaintext> &db,
                              const ClientDB &all_clients,
-                             int rnd, int epoch,
+                             int rnd, int epoch
 #ifdef DISTRIBICOM_DEBUG
-                             const seal::GaloisKeys &expansion_key
+                             ,const seal::GaloisKeys &expansion_key
 #endif
     ) {
 

diff --git a/src/services/server.cpp b/src/services/server.cpp
@@ -113,9 +113,9 @@ std::shared_ptr<services::WorkDistributionLedger> services::FullServer::distribu
 
 //        // todo: set specific round and handle.
 
-        ledger = manager.distribute_work(db_handle.mat, client_query_manager, 1, 1,
+        ledger = manager.distribute_work(db_handle.mat, client_query_manager, 1, 1
 #ifdef DISTRIBICOM_DEBUG
-                                         client_query_manager.id_to_info.begin()->second->galois_keys
+                                         ,client_query_manager.id_to_info.begin()->second->galois_keys
 #endif
         );
     }

diff --git a/test/math_utils/evaluator_wrapper_test.cpp b/test/math_utils/evaluator_wrapper_test.cpp
@@ -7,8 +7,12 @@ void order_of_ops_test1();
 
 void order_of_ops_test2(std::shared_ptr<TestUtils::CryptoObjects> all);
 
+void ctx_composition_test();
+
 int evaluator_wrapper_test(int, char *[]) {
 
+    ctx_composition_test();
+
     mult_slow_vs_modified_test();
 
     // commutative test.
@@ -211,4 +215,26 @@ void benchmark_mult() {
     std::cout << "comparing mult_slow to both mult and mult_plain: " << std::endl;
     std::cout << "mult_slow / mult:       " << double(mult_slow_time) / double(mult_time) << std::endl;
     std::cout << "mult_slow / mult_plain: " << double(mult_slow_time) / double(mult_plain_time) << std::endl;
+}
+
+void ctx_composition_test() {
+    auto all = TestUtils::setup(TestUtils::DEFAULT_SETUP_CONFIGS);
+
+    auto ptx = all->random_plaintext();
+    seal::Ciphertext enc_ptx;
+
+
+    all->encryptor.encrypt_symmetric(ptx, enc_ptx);
+
+    math_utils::EmbeddedCiphertext embedded_enc_ptx;
+
+    all->w_evaluator->get_ptx_embedding(enc_ptx, embedded_enc_ptx);
+
+    seal::Ciphertext unembedded_enc_ptx;
+    all->w_evaluator->compose_to_ctx(embedded_enc_ptx, unembedded_enc_ptx);
+
+    seal::Plaintext decrypted_unembedded_enc_ptx;
+    all->decryptor.decrypt(unembedded_enc_ptx, decrypted_unembedded_enc_ptx);
+
+    assert(decrypted_unembedded_enc_ptx.to_string() == ptx.to_string());
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -192,6 +192,7 @@ namespace math_utils { @@
                            const matrix<seal::Ciphertext> &b,
                            matrix<seal::Ciphertext> &result) const;
+            void to_ntt(std::vector<seal::Plaintext> &m) const;
         };
     }
@@ Expand Down @@