Proto changes for pir_shard_configs and reuse_existing_config (#14)

apple/swift_homomorphic_encryption/api/pir/v1/api.proto

@@ -23,6 +23,8 @@ message ConfigRequest {
   // List of usecases to fetch configs for.
   // When set to empty array, all configs will be returned.
   repeated string usecases = 1;
+  // For each usecase, the existing config id, if one exists.
+  repeated bytes existing_config_ids = 2;
 }
 
 // Usecase configuration.
@@ -35,6 +37,8 @@ message Config {
   reserved 2;
   // Unique identifier for the configuration.
   bytes config_id = 3;
+  // Indicator that the config is the same config as in the ConfigRequest. If set, all other fields can be unset.
+  bool reuse_existing_config = 4;
 }
 
 // Server side configurations.

apple/swift_homomorphic_encryption/api/pir/v1/pir.proto

@@ -40,7 +40,7 @@ message PIRShardConfig {
 message PIRConfig {
   // Encryption parameters.
   apple.swift_homomorphic_encryption.v1.EncryptionParameters encryption_parameters = 1;
-  // Configuration for each shard.
+  // Configuration for each shard; can be overridden by `pir_shard_configs` (field 10).
   repeated PIRShardConfig shard_configs = 2;
   // Parameters specific to KeywordPIR.
   apple.swift_homomorphic_encryption.pir.v1.KeywordPirParameters keyword_pir_params = 3;
@@ -50,7 +50,26 @@ message PIRConfig {
   uint64 batch_size = 5;
   // Hash of EvaluationKeyConfig.
   bytes evaluation_key_config_hash = 6;
-  reserved 7, 8;
+  reserved 7, 8, 9;
+  // Configuration for each shard; overrides `shard_configs` (field 2).
+  PIRShardConfigs pir_shard_configs = 10;
+}
+
+// Configuration for PIR shards.
+message PIRShardConfigs {
+  // Different shard configuration formats.
+  oneof shard_configs {
+    // Repeated shard configuration.
+    PIRFixedShardConfig repeated_shard_config = 1;
+  }
+}
+
+// Every shard configuration is the same.
+message PIRFixedShardConfig {
+  // Shard configuration for all the shards.
+  PIRShardConfig shard_config = 1;
+  // Number of shards.
+  uint32 shard_count = 2;
 }
 
 // PIR Request.

apple/swift_homomorphic_encryption/api/pnns/v1/api.proto

@@ -23,6 +23,8 @@ message ConfigRequest {
   // List of usecases to fetch configs for.
   // When set to empty array, all configs will be returned.
   repeated string usecases = 1;
+  // For each usecase, the existing config id, if one exists.
+  repeated bytes existing_config_ids = 2;
 }
 
 // Usecase configuration.
@@ -35,6 +37,8 @@ message Config {
   }
   // Unique identifier for the configuration.
   bytes config_id = 3;
+  // Indicator that the config is the same config as in the ConfigRequest. If set, all other fields can be unset.
+  bool reuse_existing_config = 4;
 }
 
 // Server side configurations.

apple/swift_homomorphic_encryption/api/v1/api.proto

@@ -19,6 +19,15 @@ import "apple/swift_homomorphic_encryption/api/pir/v1/pir.proto";
 import "apple/swift_homomorphic_encryption/api/pnns/v1/pnns.proto";
 import "apple/swift_homomorphic_encryption/api/shared/v1/api_shared.proto";
 
+// Request for server side configurations.
+message ConfigRequest {
+  // List of usecases to fetch configs for.
+  // When set to empty array, all configs will be returned.
+  repeated string usecases = 1;
+  // For each usecase, the existing config id, if one exists.
+  repeated bytes existing_config_ids = 2;
+}
+
 // Usecase configuration.
 message Config {
   // Configuration.
@@ -30,13 +39,8 @@ message Config {
   }
   // Unique identifier for the configuration.
   bytes config_id = 3;
-}
-
-// Request for server side configurations.
-message ConfigRequest {
-  // List of usecases to fetch configs for.
-  // When set to empty array, all configs will be returned.
-  repeated string usecases = 1;
+  // Indicator that the config is the same config as in the ConfigRequest. If set, all other fields can be unset.
+  bool reuse_existing_config = 4;
 }
 
 // Server side configurations.

apple/swift_homomorphic_encryption/pir/v1/pir.proto

@@ -58,7 +58,7 @@ message PirParameters {
 message KeywordPirParameters {
   // The number of hash functions used.
   uint64 num_hash_functions = 1;
-  reserved 2;
+  reserved 2, 3, 4;
 }
 
 // Encrypted PIR index.