From d61a34ac78a84240bc10ad0c10943274b4943567 Mon Sep 17 00:00:00 2001
From: SecAgg Team <secagg-team-bot@google.com>
Date: Sun, 24 May 2026 23:12:16 -0700
Subject: [PATCH] No public description

PiperOrigin-RevId: 920784388
---
 willow/proto/willow/BUILD           | 10 ++++++----
 willow/proto/willow/decryptor.proto | 17 +++++++++++++++++
 willow/proto/willow/key.proto       |  9 +++++++++
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/willow/proto/willow/BUILD b/willow/proto/willow/BUILD
index f543f23..ec0214d 100644
--- a/willow/proto/willow/BUILD
+++ b/willow/proto/willow/BUILD
@@ -40,10 +40,6 @@ cc_proto_library(
 proto_library(
     name = "aggregation_config_proto",
     srcs = ["aggregation_config.proto"],
-    deps = [
-        "//willow/proto/shell:shell_ciphertexts_proto",
-        "//willow/proto/zk:proofs_proto",
-    ],
 )
 
 cc_proto_library(
@@ -59,6 +55,9 @@ rust_proto_library(
 proto_library(
     name = "decryptor_proto",
     srcs = ["decryptor.proto"],
+    deps = [
+        "@protobuf//:timestamp_proto",
+    ],
 )
 
 cc_proto_library(
@@ -69,6 +68,9 @@ cc_proto_library(
 proto_library(
     name = "key_proto",
     srcs = ["key.proto"],
+    deps = [
+        "@protobuf//:timestamp_proto",
+    ],
 )
 
 cc_proto_library(
diff --git a/willow/proto/willow/decryptor.proto b/willow/proto/willow/decryptor.proto
index ff70c34..8d8aaa4 100644
--- a/willow/proto/willow/decryptor.proto
+++ b/willow/proto/willow/decryptor.proto
@@ -16,6 +16,8 @@ syntax = "proto3";
 
 package secure_aggregation.willow;
 
+import "google/protobuf/timestamp.proto";
+
 option java_multiple_files = true;
 option java_outer_classname = "DecryptorProto";
 
@@ -23,11 +25,23 @@ message GenerateKeyRequest {
   // The key ID to use for the generated key. If the key with the given ID
   // already exists, it will be returned instead.
   bytes key_id = 1;
+
+  // A permanent session_tag that is shared across all keys mapped to the same
+  // logical recurring task. To avoid race condition in a potentially costly,
+  // key generation operation, only one key per session tag can be generated at
+  // a time.
+  string session_tag = 2;
+
+  // The timestamp that indicates when the key was produced. This is used to
+  // distinguish keys in the same series.
+  google.protobuf.Timestamp timestamp = 3;
 }
 
 message GenerateKeyResponse {
   // The serialized bytes of the public key.
   bytes public_key = 1;
+  // The key_id of the generated key.
+  bytes key_id = 2;
 }
 
 message DecryptRequest {
@@ -37,6 +51,9 @@ message DecryptRequest {
   bytes public_key = 2 [deprecated = true];
   // The key ID of the public key that was used in the GenerateKey call.
   bytes key_id = 3;
+  // Session tag associated with the key. Even though this isn't strictly
+  // required, it is good include this for diagnostic purposes.
+  string session_tag = 4;
 }
 
 message DecryptResponse {
diff --git a/willow/proto/willow/key.proto b/willow/proto/willow/key.proto
index 7b24f08..101125c 100644
--- a/willow/proto/willow/key.proto
+++ b/willow/proto/willow/key.proto
@@ -16,6 +16,8 @@ syntax = "proto3";
 
 package secure_aggregation.willow;
 
+import "google/protobuf/timestamp.proto";
+
 option java_multiple_files = true;
 option java_outer_classname = "KeyProto";
 
@@ -29,4 +31,11 @@ message Key {
   // The raw key material. This is the serialized bytes of the key material
   // returned by the key generation service.
   bytes key_material = 2;
+
+  // The timestamp that indicates when the key was produced. This is used to
+  // distinguish keys in the same series.
+  google.protobuf.Timestamp timestamp = 3;
+
+  // We might consider the original session_tage for diagnostic purposes.
+  string session_tag = 4;
 }