feat(rpc): add replay-scoped internode authentication (#5455)

crates/config/src/constants/internode.rs

@@ -158,17 +158,33 @@ pub const DEFAULT_INTERNODE_RPC_BODY_DIGEST_STRICT: bool = false;
 // rolling upgrades until the fleet-wide body-digest fallback counter reads zero.
 const _: () = assert!(!DEFAULT_INTERNODE_RPC_BODY_DIGEST_STRICT);
 
-/// Capacity (distinct nonces) of the process-local internode RPC replay cache that enforces
-/// one-time consumption of body-bound v2 signatures.
+/// Require the replay-scoped internode RPC signature after the fleet has converged on it.
 ///
-/// The cache retains each nonce for the ~10-minute signature freshness envelope, so the steady
-/// state holds roughly `mutating RPS x 601s` entries; the default sustains ~1,700 body-bound
-/// mutating RPCs per second (about 120 MiB worst case, allocated only under sustained load).
-/// Overflow fails closed — legitimate signed traffic is the only thing that can fill the cache
-/// (replays are rejected before insertion, and an attacker cannot mint valid nonces without the
-/// shared secret) — and increments
+/// The default keeps v1/v2 peers available during a rolling upgrade. Operators may set this only
+/// after `rustfs_system_network_internode_replay_scope_fallback_total` remains zero for a full
+/// release window. The node still accepts a v2-authenticated `Ping` carrying an epoch challenge:
+/// that narrowly scoped bootstrap lets an upgraded client learn the receiving process epoch and
+/// immediately retry with the replay-scoped signature after a peer restart.
+pub const ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT: &str = "RUSTFS_INTERNODE_RPC_REPLAY_SCOPE_STRICT";
+pub const DEFAULT_INTERNODE_RPC_REPLAY_SCOPE_STRICT: bool = false;
+
+// Compile-time invariant: mixed-version clusters must remain available until operators make the
+// observed fallback counter an explicit strictness decision.
+const _: () = assert!(!DEFAULT_INTERNODE_RPC_REPLAY_SCOPE_STRICT);
+
+/// Capacity (distinct nonces) of the process-local internode RPC replay cache that enforces
+/// one-time consumption of authenticated RPC signatures.
+///
+/// The cache retains each nonce for the ~10-minute signature freshness envelope. Once peers use
+/// replay-scoped v3 authentication, every authenticated RPC consumes one entry, so the steady
+/// state holds roughly `authenticated RPC RPS x 601s` entries. The default sustains about 1,700
+/// authenticated RPCs per second (about 120 MiB worst case, allocated only under sustained load);
+/// operators must size it for the node's aggregate peak RPC rate before enabling strict replay
+/// scope. Overflow fails closed — legitimate signed traffic is the only thing that can fill the
+/// cache (replays are rejected before insertion, and an attacker cannot mint valid nonces without
+/// the shared secret) — and increments
 /// `rustfs_system_network_internode_replay_cache_overflow_total`, so a sustained non-zero overflow
-/// counter means this capacity is undersized for the node's peak mutation rate.
+/// counter means this capacity is undersized for the node's peak authenticated RPC rate.
 pub const ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY: &str = "RUSTFS_INTERNODE_RPC_REPLAY_CACHE_CAPACITY";
 pub const DEFAULT_INTERNODE_RPC_REPLAY_CACHE_CAPACITY: usize = 1_048_576;
 
@@ -354,6 +370,12 @@ mod tests {
         assert_eq!(ENV_INTERNODE_RPC_BODY_DIGEST_STRICT, "RUSTFS_INTERNODE_RPC_BODY_DIGEST_STRICT");
     }
 
+    #[test]
+    fn internode_replay_scope_strict_env_name_is_stable() {
+        // The fail-open default invariant is asserted at compile time next to the definition.
+        assert_eq!(ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT, "RUSTFS_INTERNODE_RPC_REPLAY_SCOPE_STRICT");
+    }
+
     #[test]
     fn internode_replay_cache_capacity_defaults_and_env_name() {
         assert_eq!(ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY, "RUSTFS_INTERNODE_RPC_REPLAY_CACHE_CAPACITY");

crates/e2e_test/src/internode_rpc_signature_e2e_test.rs

@@ -13,8 +13,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Cross-process replay / tamper acceptance for the internode NodeService v2 RPC
-//! signature (<https://github.com/rustfs/backlog/issues/1327>).
+//! Cross-process replay / tamper acceptance for internode NodeService RPC
+//! signatures (<https://github.com/rustfs/backlog/issues/1327>,
+//! <https://github.com/rustfs/backlog/issues/1542>).
 //!
 //! # Why this exists on top of the in-process tests
 //!
@@ -78,6 +79,8 @@
 //! | mixed version: legacy-only still served, not blocked | [`legacy_only_signature_is_accepted_in_default_posture`] |
 //! | strict flip closes the signature downgrade | [`signature_strict_rejects_legacy_only_downgrade`] |
 //! | strict flip closes the body-digest downgrade, incl. v1 | [`body_digest_strict_rejects_digestless_mutation`] |
+//! | replay scope binds every RPC and rejects restart replay | [`replay_scope_rejects_replay_path_transplant_and_stale_epoch_e2e`] |
+//! | strict replay scope allows only Ping bootstrap before v3 | [`replay_scope_strict_requires_v3_after_ping_bootstrap_e2e`] |
 //!
 //! Two acceptance items are deliberately left to the in-process tests. A stale
 //! timestamp cannot be forged from outside — it is inside the HMAC — so
@@ -88,18 +91,20 @@
 
 use crate::common::{RustFSTestEnvironment, init_logging};
 use crate::storage_api::internode_rpc_signature::{
-    TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_signature_headers, node_service_time_out_client_no_auth,
+    TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_replay_scope_headers, gen_tonic_signature_headers,
+    node_service_time_out_client_no_auth, verify_tonic_boot_epoch_response,
 };
 use http::{HeaderMap, Method};
 use rustfs_config::{
-    ENV_INTERNODE_RPC_BODY_DIGEST_STRICT, ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY, ENV_INTERNODE_RPC_SIGNATURE_STRICT,
+    ENV_INTERNODE_RPC_BODY_DIGEST_STRICT, ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY, ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT,
+    ENV_INTERNODE_RPC_SIGNATURE_STRICT,
 };
 use rustfs_protos::canonical_make_volume_request_body;
-use rustfs_protos::proto_gen::node_service::{MakeVolumeRequest, MakeVolumeResponse};
+use rustfs_protos::proto_gen::node_service::{MakeVolumeRequest, MakeVolumeResponse, PingRequest, PingResponse};
 use serial_test::serial;
 use sha2::{Digest, Sha256};
 use std::error::Error;
-use tonic::{Code, Request, Status};
+use tonic::{Code, Request, Response, Status};
 use uuid::Uuid;
 
 type TestResult = Result<(), Box<dyn Error + Send + Sync>>;
@@ -115,12 +120,14 @@ const TEST_RPC_SECRET: &str = "rustfs-internode-signature-e2e-secret";
 /// clears authentication stops harmlessly at `find_disk`.
 const ABSENT_DISK: &str = "/nonexistent/rustfs-signature-e2e-disk";
 
-/// Wire names of the two v2 headers these tests edit. They are `pub(crate)` in
-/// ecstore, so they are repeated here rather than imported — [`overwrite_header`]
-/// asserts the header it replaces was actually present, which turns a rename
-/// into a loud failure instead of silently reducing an attack to a no-op.
+/// Wire names of the v2 and replay-scope headers these black-box tests edit. They are
+/// `pub(crate)` in ecstore, so they are repeated here rather than imported.
+/// [`overwrite_header`] asserts the header it replaces was actually present, which turns a
+/// rename into a loud failure instead of silently reducing an attack to a no-op.
 const CONTENT_SHA256_HEADER: &str = "x-rustfs-content-sha256";
 const NONCE_HEADER: &str = "x-rustfs-rpc-nonce";
+const TIMESTAMP_HEADER: &str = "x-rustfs-timestamp";
+const BOOT_EPOCH_CHALLENGE_HEADER: &str = "x-rustfs-rpc-boot-epoch-challenge";
 
 /// gRPC service name carried in the signed scope, i.e. `TONIC_RPC_PREFIX`
 /// without its leading `/`.
@@ -155,19 +162,28 @@ fn align_rpc_secret_with_server() {
 ///
 /// Uses the no-cleanup spawn so a `pkill` pattern cannot reap servers belonging
 /// to other tests running in the same binary.
-async fn start_server(extra_env: &[(&str, &str)]) -> Result<RustFSTestEnvironment, Box<dyn Error + Send + Sync>> {
-    let mut env = RustFSTestEnvironment::new().await?;
+fn server_env(extra_env: &[(&'static str, &'static str)]) -> Vec<(&'static str, &'static str)> {
     let mut child_env = vec![
         ("RUSTFS_RPC_SECRET", TEST_RPC_SECRET),
         (ENV_INTERNODE_RPC_SIGNATURE_STRICT, "false"),
         (ENV_INTERNODE_RPC_BODY_DIGEST_STRICT, "false"),
+        (ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT, "false"),
         (ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY, "1048576"),
     ];
     child_env.extend_from_slice(extra_env);
-    env.start_rustfs_server_without_cleanup_with_env(&child_env).await?;
+    child_env
+}
+
+async fn start_server_with_env(child_env: &[(&str, &str)]) -> Result<RustFSTestEnvironment, Box<dyn Error + Send + Sync>> {
+    let mut env = RustFSTestEnvironment::new().await?;
+    env.start_rustfs_server_without_cleanup_with_env(child_env).await?;
     Ok(env)
 }
 
+async fn start_server(extra_env: &[(&'static str, &'static str)]) -> Result<RustFSTestEnvironment, Box<dyn Error + Send + Sync>> {
+    start_server_with_env(&server_env(extra_env)).await
+}
+
 /// Stop the child and drop the cached gRPC channel for its address.
 ///
 /// `node_service_time_out_client_no_auth` memoises channels in a process-global
@@ -238,12 +254,83 @@ fn overwrite_header(headers: &mut HeaderMap, name: &'static str, value: &str) {
 /// and nothing else — no interceptor adds or rewrites auth metadata, so the
 /// bytes on the wire are the ones the test chose.
 async fn call_make_volume(url: &str, request: MakeVolumeRequest, headers: HeaderMap) -> Result<MakeVolumeResponse, Status> {
+    call_make_volume_response(url, request, headers)
+        .await
+        .map(Response::into_inner)
+}
+
+async fn call_make_volume_response(
+    url: &str,
+    request: MakeVolumeRequest,
+    headers: HeaderMap,
+) -> Result<Response<MakeVolumeResponse>, Status> {
     let mut client = node_service_time_out_client_no_auth(&url.to_string())
         .await
         .map_err(|err| Status::unavailable(format!("cannot reach the node service: {err}")))?;
     let mut rpc_request = Request::new(request);
     rpc_request.metadata_mut().as_mut().extend(headers);
-    client.make_volume(rpc_request).await.map(|response| response.into_inner())
+    client.make_volume(rpc_request).await
+}
+
+async fn call_ping_response(url: &str, headers: HeaderMap) -> Result<Response<PingResponse>, Status> {
+    let mut client = node_service_time_out_client_no_auth(&url.to_string())
+        .await
+        .map_err(|err| Status::unavailable(format!("cannot reach the node service: {err}")))?;
+    let mut rpc_request = Request::new(PingRequest {
+        version: 1,
+        body: bytes::Bytes::new(),
+    });
+    rpc_request.metadata_mut().as_mut().extend(headers);
+    client.ping(rpc_request).await
+}
+
+fn attach_boot_epoch_challenge(headers: &mut HeaderMap) -> Uuid {
+    let challenge = Uuid::new_v4();
+    headers.insert(
+        BOOT_EPOCH_CHALLENGE_HEADER,
+        challenge.to_string().parse().expect("UUID must be a valid header value"),
+    );
+    challenge
+}
+
+fn mint_replay_scope_headers(audience: &str, path: &str, content_sha256: &str, boot_epoch: Uuid) -> HeaderMap {
+    let mut headers = mint_v2_headers(audience, "MakeVolume", Some(content_sha256));
+    let timestamp = headers
+        .get(TIMESTAMP_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .expect("v2 headers must carry a timestamp")
+        .to_string();
+    headers.extend(
+        gen_tonic_replay_scope_headers(audience, path, &timestamp, content_sha256, boot_epoch)
+            .expect("replay-scope headers must mint with the aligned RPC secret"),
+    );
+    headers
+}
+
+async fn learn_boot_epoch_from_make_volume(url: &str, audience: &str) -> Uuid {
+    let request = make_volume_request("signature-e2e-epoch-bootstrap");
+    let mut headers = mint_v2_headers(audience, "MakeVolume", Some(&canonical_digest(&request)));
+    let challenge = attach_boot_epoch_challenge(&mut headers);
+    let response = call_make_volume_response(url, request, headers)
+        .await
+        .expect("v2 request with epoch challenge must clear default authentication");
+    let boot_epoch = verify_tonic_boot_epoch_response(audience, challenge, response.metadata().as_ref())
+        .expect("server must HMAC-authenticate the advertised boot epoch");
+    assert_authenticated(
+        Ok(response.into_inner()),
+        "a v2 epoch-challenge request in the default replay-scope posture",
+    );
+    boot_epoch
+}
+
+async fn learn_boot_epoch_from_ping(url: &str, audience: &str) -> Uuid {
+    let mut headers = mint_v2_headers(audience, "Ping", None);
+    let challenge = attach_boot_epoch_challenge(&mut headers);
+    let response = call_ping_response(url, headers)
+        .await
+        .expect("v2 Ping with an epoch challenge must bootstrap strict replay scope");
+    verify_tonic_boot_epoch_response(audience, challenge, response.metadata().as_ref())
+        .expect("strict replay-scope Ping must return a valid boot epoch proof")
 }
 
 /// Assert a call cleared authentication.
@@ -332,6 +419,122 @@ async fn internode_rpc_signature_default_posture_e2e() -> TestResult {
     Ok(())
 }
 
+/// A replay-scoped signature is usable exactly once against the exact gRPC path and the server
+/// process epoch that minted it. This crosses the child-process boundary twice: the HMAC-protected
+/// epoch is learned from a real response, then the same server is restarted in place to prove its
+/// replacement epoch rejects the captured request even though the nonce cache is necessarily new.
+#[tokio::test]
+#[serial]
+async fn replay_scope_rejects_replay_path_transplant_and_stale_epoch_e2e() -> TestResult {
+    init_logging();
+    align_rpc_secret_with_server();
+    let child_env = server_env(&[]);
+    let mut env = start_server_with_env(&child_env).await?;
+    let url = env.url.clone();
+    let audience = audience_of(&env);
+    let boot_epoch = learn_boot_epoch_from_make_volume(&url, &audience).await;
+
+    let request = make_volume_request("replay-scope-e2e-once");
+    let captured = mint_replay_scope_headers(
+        &audience,
+        &format!("{TONIC_RPC_PREFIX}/MakeVolume"),
+        &canonical_digest(&request),
+        boot_epoch,
+    );
+    assert_authenticated(
+        call_make_volume(&url, request.clone(), captured.clone()).await,
+        "the first replay-scoped mutation delivery",
+    );
+    assert_rejected(
+        call_make_volume(&url, request.clone(), captured).await,
+        Code::Unauthenticated,
+        None,
+        "the same replay-scoped mutation delivered twice",
+    );
+
+    let transplanted =
+        mint_replay_scope_headers(&audience, &format!("{TONIC_RPC_PREFIX}/Ping"), &canonical_digest(&request), boot_epoch);
+    assert_rejected(
+        call_make_volume(&url, request.clone(), transplanted).await,
+        Code::Unauthenticated,
+        None,
+        "a replay-scoped Ping signature transplanted onto MakeVolume",
+    );
+
+    let stale_epoch = mint_replay_scope_headers(
+        &audience,
+        &format!("{TONIC_RPC_PREFIX}/MakeVolume"),
+        &canonical_digest(&request),
+        boot_epoch,
+    );
+    env.restart_server_preserving_data(Vec::new(), &child_env).await?;
+    rustfs_protos::evict_failed_connection(&url).await;
+    assert_rejected(
+        call_make_volume(&url, request.clone(), stale_epoch).await,
+        Code::Unauthenticated,
+        None,
+        "a replay-scoped signature captured before the receiving process restart",
+    );
+
+    let restarted_epoch = learn_boot_epoch_from_make_volume(&url, &audience).await;
+    assert_ne!(boot_epoch, restarted_epoch, "a restarted child process must advertise a new boot epoch");
+    let fresh_epoch = mint_replay_scope_headers(
+        &audience,
+        &format!("{TONIC_RPC_PREFIX}/MakeVolume"),
+        &canonical_digest(&request),
+        restarted_epoch,
+    );
+    assert_authenticated(
+        call_make_volume(&url, request, fresh_epoch).await,
+        "a replay-scoped mutation signed with the replacement process epoch",
+    );
+
+    stop_server(env, &url).await;
+    Ok(())
+}
+
+/// Strict replay scope leaves one authenticated v2 bootstrap: `Ping` carrying a fresh challenge.
+/// A mutating v2 request cannot use that lane; once the epoch proof is returned, the first v3
+/// mutation succeeds. This protects a server restart without reopening a general downgrade path.
+#[tokio::test]
+#[serial]
+async fn replay_scope_strict_requires_v3_after_ping_bootstrap_e2e() -> TestResult {
+    init_logging();
+    align_rpc_secret_with_server();
+    let env = start_server(&[(ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT, "true")]).await?;
+    let url = env.url.clone();
+    let audience = audience_of(&env);
+
+    let v2_request = make_volume_request("replay-scope-e2e-strict-v2");
+    assert_rejected(
+        call_make_volume(
+            &url,
+            v2_request.clone(),
+            mint_v2_headers(&audience, "MakeVolume", Some(&canonical_digest(&v2_request))),
+        )
+        .await,
+        Code::Unauthenticated,
+        None,
+        "a v2 mutation after replay-scope strictness is enabled",
+    );
+
+    let boot_epoch = learn_boot_epoch_from_ping(&url, &audience).await;
+    let request = make_volume_request("replay-scope-e2e-strict-v3");
+    let replay_scoped = mint_replay_scope_headers(
+        &audience,
+        &format!("{TONIC_RPC_PREFIX}/MakeVolume"),
+        &canonical_digest(&request),
+        boot_epoch,
+    );
+    assert_authenticated(
+        call_make_volume(&url, request, replay_scoped).await,
+        "a replay-scoped mutation after Ping bootstrap under strict replay scope",
+    );
+
+    stop_server(env, &url).await;
+    Ok(())
+}
+
 /// Baseline: correctly signed mutations are accepted, both with and without a
 /// body digest.
 ///

crates/e2e_test/src/reliant/grpc_lock_client.rs

@@ -24,7 +24,7 @@ use rustfs_protos::proto_gen::node_service::{BatchGenerallyLockRequest, Generall
 use tonic::Request;
 use tracing::{info, warn};
 
-use crate::storage_api::grpc_lock::{TonicInterceptor, node_service_time_out_client_no_auth};
+use crate::storage_api::grpc_lock::{AuthenticatedChannel, TonicInterceptor, node_service_time_out_client_no_auth};
 
 /// gRPC lock client without authentication for testing
 /// Similar to RemoteClient but uses no_auth client
@@ -42,7 +42,7 @@ impl GrpcLockClient {
         &self,
     ) -> Result<
         rustfs_protos::proto_gen::node_service::node_service_client::NodeServiceClient<
-            tonic::service::interceptor::InterceptedService<tonic::transport::Channel, TonicInterceptor>,
+            tonic::service::interceptor::InterceptedService<AuthenticatedChannel, TonicInterceptor>,
         >,
     > {
         node_service_time_out_client_no_auth(&self.addr)

crates/e2e_test/src/storage_api.rs

@@ -16,9 +16,12 @@
 pub(crate) use rustfs_ecstore::api::bucket::bucket_target_sys::BucketTargetSys;
 #[cfg(test)]
 pub(crate) use rustfs_ecstore::api::disk::{VolumeInfo, WalkDirOptions};
+pub(crate) use rustfs_ecstore::api::rpc::{AuthenticatedChannel, TonicInterceptor, node_service_time_out_client_no_auth};
 #[cfg(test)]
-pub(crate) use rustfs_ecstore::api::rpc::{TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_signature_headers};
-pub(crate) use rustfs_ecstore::api::rpc::{TonicInterceptor, node_service_time_out_client_no_auth};
+pub(crate) use rustfs_ecstore::api::rpc::{
+    TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_replay_scope_headers, gen_tonic_signature_headers,
+    verify_tonic_boot_epoch_response,
+};
 #[cfg(test)]
 pub(crate) use rustfs_ecstore::api::rpc::{gen_tonic_signature_interceptor, node_service_time_out_client};
 
@@ -30,7 +33,7 @@ pub(crate) mod node_interact {
 }
 
 pub(crate) mod grpc_lock {
-    pub(crate) use super::{TonicInterceptor, node_service_time_out_client_no_auth};
+    pub(crate) use super::{AuthenticatedChannel, TonicInterceptor, node_service_time_out_client_no_auth};
 }
 
 /// Signing/transport surface used by the cross-process internode RPC signature
@@ -40,7 +43,8 @@ pub(crate) mod grpc_lock {
 #[cfg(test)]
 pub(crate) mod internode_rpc_signature {
     pub(crate) use super::{
-        TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_signature_headers, node_service_time_out_client_no_auth,
+        TONIC_RPC_PREFIX, gen_signature_headers, gen_tonic_replay_scope_headers, gen_tonic_signature_headers,
+        node_service_time_out_client_no_auth, verify_tonic_boot_epoch_response,
     };
 }
 

crates/ecstore/src/api/mod.rs

@@ -416,13 +416,15 @@ pub mod rio {
 
 pub mod rpc {
     pub use crate::cluster::rpc::{
-        LocalPeerS3Client, PEER_RESTDRY_RUN, PEER_RESTSIGNAL, PEER_RESTSUB_SYS, PeerRestClient, PeerS3Client, S3PeerSys,
-        SERVICE_SIGNAL_REFRESH_CONFIG, SERVICE_SIGNAL_RELOAD_DYNAMIC, ScannerBucketListing, ScannerPeerActivity,
-        TONIC_RPC_PREFIX, TonicInterceptor, gen_signature_headers, gen_tonic_signature_headers, gen_tonic_signature_interceptor,
-        node_service_time_out_client, node_service_time_out_client_no_auth, normalize_tonic_rpc_audience,
-        set_tonic_canonical_body_digest, sign_ns_scanner_capability, sign_tonic_rpc_response_proof, verify_rpc_signature,
-        verify_tonic_canonical_body_digest, verify_tonic_mutation_body_digest, verify_tonic_rpc_response_proof,
-        verify_tonic_rpc_signature,
+        AuthenticatedChannel, LocalPeerS3Client, PEER_RESTDRY_RUN, PEER_RESTSIGNAL, PEER_RESTSUB_SYS, PeerRestClient,
+        PeerS3Client, S3PeerSys, SERVICE_SIGNAL_REFRESH_CONFIG, SERVICE_SIGNAL_RELOAD_DYNAMIC, ScannerBucketListing,
+        ScannerPeerActivity, TONIC_RPC_PREFIX, TonicInterceptor, gen_signature_headers, gen_tonic_replay_scope_headers,
+        gen_tonic_signature_headers, gen_tonic_signature_interceptor, node_service_time_out_client,
+        node_service_time_out_client_no_auth, normalize_tonic_rpc_audience, set_tonic_canonical_body_digest,
+        sign_ns_scanner_capability, sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers,
+        verify_rpc_signature, verify_tonic_boot_epoch_response, verify_tonic_canonical_body_digest,
+        verify_tonic_mutation_body_digest, verify_tonic_rpc_response_proof, verify_tonic_rpc_signature,
+        verify_tonic_rpc_signature_with_bootstrap,
     };
 }
 

crates/ecstore/src/cluster/rpc/client.rs

@@ -12,11 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::cluster::rpc::http_auth::RPC_CONTENT_SHA256_HEADER;
-use crate::cluster::rpc::{gen_tonic_signature_headers, normalize_tonic_rpc_audience};
+#[cfg(test)]
+use crate::cluster::rpc::http_auth::RPC_REPLAY_SCOPE_VERSION_HEADER;
+use crate::cluster::rpc::http_auth::{
+    RPC_AUTH_VERSION_HEADER, RPC_AUTH_VERSION_V2, RPC_BOOT_EPOCH_CHALLENGE_HEADER, RPC_BOOT_EPOCH_HEADER,
+    RPC_BOOT_EPOCH_PROOF_HEADER, RPC_CONTENT_SHA256_HEADER, TIMESTAMP_HEADER,
+};
+use crate::cluster::rpc::{
+    gen_tonic_replay_scope_headers, gen_tonic_signature_headers, normalize_tonic_rpc_audience, verify_tonic_boot_epoch_response,
+};
+#[cfg(test)]
+use crate::cluster::rpc::{tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers};
 use crate::disk::error::{DiskError, Error as DiskErrorType, RpcStatusError};
 use crate::runtime::sources as runtime_sources;
-use http::Uri;
+use http::{Request as HttpRequest, Response as HttpResponse, Uri};
 use rustfs_protos::{
     ChannelClass, create_new_channel, get_channel_for_class,
     proto_gen::node_service::{
@@ -24,9 +33,19 @@ use rustfs_protos::{
         tier_mutation_control_service_client::TierMutationControlServiceClient,
     },
 };
-use std::{error::Error, io::ErrorKind};
+use std::{
+    collections::HashMap,
+    error::Error,
+    future::Future,
+    io::ErrorKind,
+    pin::Pin,
+    sync::{LazyLock, Mutex},
+    task::{Context, Poll},
+};
 use tonic::{service::interceptor::InterceptedService, transport::Channel};
+use tower::Service;
 use tracing::debug;
+use uuid::Uuid;
 
 use super::context_propagation::{inject_request_id_into_metadata, inject_trace_context_into_metadata};
 
@@ -35,7 +54,7 @@ use super::context_propagation::{inject_request_id_into_metadata, inject_trace_c
 pub async fn node_service_time_out_client(
     addr: &String,
     interceptor: TonicInterceptor,
-) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>, Box<dyn Error>> {
+) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>, Box<dyn Error>> {
     // Default to the latency-sensitive control channel; bulk `bytes` RPCs opt in via the
     // `_for_class` variant below (grpc-optimization P1).
     node_service_time_out_client_for_class(addr, interceptor, ChannelClass::Control).await
@@ -44,13 +63,14 @@ pub async fn node_service_time_out_client(
 pub async fn heal_control_time_out_client(
     addr: &str,
     interceptor: TonicInterceptor,
-) -> Result<HealControlServiceClient<InterceptedService<Channel, TonicInterceptor>>, Box<dyn Error>> {
+) -> Result<HealControlServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>, Box<dyn Error>> {
     let interceptor = interceptor.with_rpc_audience(addr)?;
     let channel = match runtime_sources::cached_node_channel(addr).await {
         Some(channel) => channel,
         None => create_new_channel(addr).await?,
     };
     let max_message_size = rustfs_protos::HEAL_CONTROL_RPC_MAX_MESSAGE_SIZE;
+    let channel = ReplayScopeChannel::new(channel, interceptor.replay_scope_audience());
     Ok(HealControlServiceClient::with_interceptor(channel, interceptor)
         .max_decoding_message_size(max_message_size)
         .max_encoding_message_size(max_message_size))
@@ -59,13 +79,14 @@ pub async fn heal_control_time_out_client(
 pub async fn tier_mutation_control_time_out_client(
     addr: &str,
     interceptor: TonicInterceptor,
-) -> Result<TierMutationControlServiceClient<InterceptedService<Channel, TonicInterceptor>>, Box<dyn Error>> {
+) -> Result<TierMutationControlServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>, Box<dyn Error>> {
     let interceptor = interceptor.with_rpc_audience(addr)?;
     let channel = match runtime_sources::cached_node_channel(addr).await {
         Some(channel) => channel,
         None => create_new_channel(addr).await?,
     };
     let max_message_size = rustfs_protos::TIER_MUTATION_RPC_MAX_MESSAGE_SIZE;
+    let channel = ReplayScopeChannel::new(channel, interceptor.replay_scope_audience());
     Ok(TierMutationControlServiceClient::with_interceptor(channel, interceptor)
         .max_decoding_message_size(max_message_size)
         .max_encoding_message_size(max_message_size))
@@ -81,7 +102,7 @@ pub async fn node_service_time_out_client_for_class(
     addr: &String,
     interceptor: TonicInterceptor,
     class: ChannelClass,
-) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>, Box<dyn Error>> {
+) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>, Box<dyn Error>> {
     let interceptor = interceptor.with_rpc_audience(addr)?;
     let channel = match class {
         ChannelClass::Control => match runtime_sources::cached_node_channel(addr).await {
@@ -96,6 +117,7 @@ pub async fn node_service_time_out_client_for_class(
     };
 
     let max_message_size = rustfs_protos::internode_rpc_max_message_size();
+    let channel = ReplayScopeChannel::new(channel, interceptor.replay_scope_audience());
     Ok(NodeServiceClient::with_interceptor(channel, interceptor)
         .max_decoding_message_size(max_message_size)
         .max_encoding_message_size(max_message_size))
@@ -103,7 +125,7 @@ pub async fn node_service_time_out_client_for_class(
 
 pub async fn node_service_time_out_client_no_auth(
     addr: &String,
-) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>, Box<dyn Error>> {
+) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>, Box<dyn Error>> {
     node_service_time_out_client(addr, TonicInterceptor::NoOp(NoOpInterceptor)).await
 }
 
@@ -199,6 +221,104 @@ pub(crate) fn is_network_like_disk_error(err: &DiskErrorType) -> bool {
     }
 }
 
+/// The transport service that learns an authenticated peer boot epoch and adds the replay-scoped
+/// signature only after one has been observed. The v1/v2 interceptor stays inside this wrapper so
+/// old servers continue receiving precisely the metadata they understand.
+#[derive(Clone, Debug)]
+pub struct ReplayScopeChannel<S> {
+    inner: S,
+    audience: Option<String>,
+}
+
+/// The channel type used by internode clients after v2 authentication and replay-scope handling.
+pub type AuthenticatedChannel = ReplayScopeChannel<Channel>;
+
+static PEER_BOOT_EPOCHS: LazyLock<Mutex<HashMap<String, Uuid>>> = LazyLock::new(|| Mutex::new(HashMap::new()));
+
+impl<S> ReplayScopeChannel<S> {
+    fn new(inner: S, audience: Option<String>) -> Self {
+        Self { inner, audience }
+    }
+}
+
+fn cached_peer_boot_epoch(audience: &str) -> Option<Uuid> {
+    PEER_BOOT_EPOCHS.lock().ok().and_then(|epochs| epochs.get(audience).copied())
+}
+
+fn remember_peer_boot_epoch(audience: String, epoch: Uuid) {
+    if let Ok(mut epochs) = PEER_BOOT_EPOCHS.lock() {
+        epochs.insert(audience, epoch);
+    }
+}
+
+impl<S, ReqBody, ResBody> Service<HttpRequest<ReqBody>> for ReplayScopeChannel<S>
+where
+    S: Service<HttpRequest<ReqBody>, Response = HttpResponse<ResBody>>,
+    S::Error: Send + 'static,
+    S::Future: Send + 'static,
+    ReqBody: Send + 'static,
+    ResBody: Send + 'static,
+{
+    type Response = HttpResponse<ResBody>;
+    type Error = S::Error;
+    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner.poll_ready(cx)
+    }
+
+    fn call(&mut self, mut request: HttpRequest<ReqBody>) -> Self::Future {
+        let authenticated = self.audience.as_ref().is_some_and(|_| {
+            request
+                .headers()
+                .get(RPC_AUTH_VERSION_HEADER)
+                .and_then(|value| value.to_str().ok())
+                == Some(RPC_AUTH_VERSION_V2)
+        });
+        let challenge = authenticated.then(Uuid::new_v4);
+        if let (Some(audience), Some(challenge)) = (self.audience.as_deref(), challenge) {
+            // The challenge is independently HMAC-authenticated by the response proof. It is not
+            // part of v2 so old peers ignore it, while a new peer can safely advertise its epoch.
+            request.headers_mut().insert(
+                RPC_BOOT_EPOCH_CHALLENGE_HEADER,
+                challenge.to_string().parse().expect("UUID must be a valid header value"),
+            );
+            if let (Some(boot_epoch), Some(timestamp), Some(content_sha256)) = (
+                cached_peer_boot_epoch(audience),
+                request.headers().get(TIMESTAMP_HEADER).and_then(|value| value.to_str().ok()),
+                request
+                    .headers()
+                    .get(RPC_CONTENT_SHA256_HEADER)
+                    .and_then(|value| value.to_str().ok()),
+            ) {
+                match gen_tonic_replay_scope_headers(audience, request.uri().path(), timestamp, content_sha256, boot_epoch) {
+                    Ok(headers) => request.headers_mut().extend(headers),
+                    Err(error) => debug!(error = %error, "could not attach replay-scoped RPC signature"),
+                }
+            }
+        }
+
+        let audience = self.audience.clone();
+        let future = self.inner.call(request);
+        Box::pin(async move {
+            let response = future.await?;
+            if let (Some(audience), Some(challenge)) = (audience, challenge) {
+                match verify_tonic_boot_epoch_response(&audience, challenge, response.headers()) {
+                    Ok(epoch) => remember_peer_boot_epoch(audience, epoch),
+                    Err(error)
+                        if response.headers().contains_key(RPC_BOOT_EPOCH_HEADER)
+                            || response.headers().contains_key(RPC_BOOT_EPOCH_PROOF_HEADER) =>
+                    {
+                        debug!(error = %error, "peer boot epoch response proof was rejected")
+                    }
+                    Err(_) => {}
+                }
+            }
+            Ok(response)
+        })
+    }
+}
+
 pub struct TonicSignatureInterceptor {
     audience: Option<String>,
 }
@@ -257,6 +377,13 @@ impl TonicInterceptor {
         }
         Ok(self)
     }
+
+    fn replay_scope_audience(&self) -> Option<String> {
+        match self {
+            Self::Signature(interceptor) => interceptor.audience.clone(),
+            Self::NoOp(_) => None,
+        }
+    }
 }
 
 impl tonic::service::Interceptor for TonicInterceptor {
@@ -279,6 +406,38 @@ mod tests {
     use tracing_opentelemetry::OpenTelemetrySpanExt;
     use tracing_subscriber::{Registry, layer::SubscriberExt};
 
+    #[derive(Clone)]
+    struct EpochProofService {
+        audience: String,
+        seen_headers: std::sync::Arc<Mutex<Vec<http::HeaderMap>>>,
+    }
+
+    impl Service<HttpRequest<()>> for EpochProofService {
+        type Response = HttpResponse<()>;
+        type Error = std::convert::Infallible;
+        type Future = std::future::Ready<Result<Self::Response, Self::Error>>;
+
+        fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+            Poll::Ready(Ok(()))
+        }
+
+        fn call(&mut self, request: HttpRequest<()>) -> Self::Future {
+            self.seen_headers
+                .lock()
+                .expect("test header capture lock must not be poisoned")
+                .push(request.headers().clone());
+            let challenge = tonic_boot_epoch_challenge(request.headers())
+                .expect("client challenge must be syntactically valid")
+                .expect("authenticated client request must carry a boot epoch challenge");
+            let mut response = HttpResponse::new(());
+            response.headers_mut().extend(
+                tonic_boot_epoch_response_headers(&self.audience, challenge)
+                    .expect("test server must be able to sign an epoch proof"),
+            );
+            std::future::ready(Ok(response))
+        }
+    }
+
     fn ensure_test_rpc_secret() {
         runtime_sources::ensure_test_rpc_secret();
     }
@@ -420,6 +579,52 @@ mod tests {
         assert_eq!(interceptor.audience.as_deref(), Some("node-a:9000"));
     }
 
+    #[test]
+    fn replay_scope_channel_uses_epoch_proof_before_sending_v3() {
+        ensure_test_rpc_secret();
+        let audience = "replay-scope-client-test:9000";
+        PEER_BOOT_EPOCHS
+            .lock()
+            .expect("peer epoch cache lock must not be poisoned")
+            .remove(audience);
+        let seen_headers = std::sync::Arc::new(Mutex::new(Vec::new()));
+        let service = EpochProofService {
+            audience: audience.to_string(),
+            seen_headers: seen_headers.clone(),
+        };
+        let mut channel = ReplayScopeChannel::new(service, Some(audience.to_string()));
+        let make_request = || {
+            let mut request = HttpRequest::builder()
+                .uri("/node_service.NodeService/Ping")
+                .body(())
+                .expect("test RPC request must build");
+            request.headers_mut().extend(
+                gen_tonic_signature_headers(audience, "node_service.NodeService", "Ping", None)
+                    .expect("v2 test headers must mint"),
+            );
+            request
+        };
+
+        futures::executor::block_on(channel.call(make_request())).expect("first request must complete");
+        futures::executor::block_on(channel.call(make_request())).expect("second request must complete");
+
+        let headers = seen_headers.lock().expect("test header capture lock must not be poisoned");
+        assert_eq!(headers.len(), 2);
+        assert!(headers[0].contains_key(RPC_BOOT_EPOCH_CHALLENGE_HEADER));
+        assert!(
+            !headers[0].contains_key(RPC_REPLAY_SCOPE_VERSION_HEADER),
+            "the first request must remain v2-compatible until the peer proves its epoch"
+        );
+        assert!(
+            headers[1].contains_key(RPC_REPLAY_SCOPE_VERSION_HEADER),
+            "the second request must carry the replay-scoped v3 signature"
+        );
+        PEER_BOOT_EPOCHS
+            .lock()
+            .expect("peer epoch cache lock must not be poisoned")
+            .remove(audience);
+    }
+
     #[test]
     fn test_signature_interceptor_requires_generated_method_metadata() {
         ensure_test_rpc_secret();

crates/ecstore/src/cluster/rpc/http_auth.rs

@@ -20,8 +20,8 @@
 //! rustfs/rustfs#4402) is anchored by the `ghsa_r5qv_*` tests in the module
 //! below, plus the broader negative-signature suite. The advisory class is: a
 //! node must never accept an RPC whose auth is missing, malformed, or signed
-//! with the default/empty shared secret. Body-bound v2 requests additionally
-//! receive process-local replay protection. See
+//! with the default/empty shared secret. Body-bound v2 requests and all replay-scoped v3
+//! requests additionally receive process-local replay protection. See
 //! `docs/testing/security-regressions.md` for the full advisory -> test map.
 //!
 //! Advisory: <https://github.com/rustfs/rustfs/security/advisories/GHSA-r5qv-rc46-hv8q>
@@ -50,13 +50,22 @@ use uuid::Uuid;
 type HmacSha256 = Hmac<Sha256>;
 
 const SIGNATURE_HEADER: &str = "x-rustfs-signature";
-const TIMESTAMP_HEADER: &str = "x-rustfs-timestamp";
-const RPC_AUTH_VERSION_HEADER: &str = "x-rustfs-rpc-auth-version";
+pub(crate) const TIMESTAMP_HEADER: &str = "x-rustfs-timestamp";
+pub(crate) const RPC_AUTH_VERSION_HEADER: &str = "x-rustfs-rpc-auth-version";
 const RPC_SIGNATURE_V2_HEADER: &str = "x-rustfs-rpc-signature-v2";
 const RPC_NONCE_HEADER: &str = "x-rustfs-rpc-nonce";
 pub(crate) const RPC_CONTENT_SHA256_HEADER: &str = "x-rustfs-content-sha256";
-const RPC_AUTH_VERSION_V2: &str = "2";
+pub(crate) const RPC_AUTH_VERSION_V2: &str = "2";
+pub const RPC_REPLAY_SCOPE_VERSION_HEADER: &str = "x-rustfs-rpc-replay-scope-version";
+pub const RPC_REPLAY_SCOPE_SIGNATURE_HEADER: &str = "x-rustfs-rpc-signature-v3";
+pub const RPC_REPLAY_SCOPE_NONCE_HEADER: &str = "x-rustfs-rpc-replay-nonce";
+pub const RPC_BOOT_EPOCH_HEADER: &str = "x-rustfs-rpc-boot-epoch";
+pub const RPC_BOOT_EPOCH_CHALLENGE_HEADER: &str = "x-rustfs-rpc-boot-epoch-challenge";
+pub const RPC_BOOT_EPOCH_PROOF_HEADER: &str = "x-rustfs-rpc-boot-epoch-proof";
+const RPC_REPLAY_SCOPE_VERSION_V3: &str = "3";
 const RPC_RESPONSE_PROOF_DOMAIN: &[u8] = b"rustfs-rpc-response-proof-v1\0";
+const RPC_REPLAY_SCOPE_DOMAIN: &[u8] = b"rustfs-rpc-replay-scope-v3\0";
+const RPC_BOOT_EPOCH_PROOF_DOMAIN: &[u8] = b"rustfs-rpc-boot-epoch-proof-v1\0";
 const UNSIGNED_PAYLOAD: &str = "UNSIGNED-PAYLOAD";
 const UNSIGNED_PAYLOAD_NONCE: &str = "unsigned";
 const SIGNATURE_VALID_DURATION: i64 = 300; // 5 minutes
@@ -75,9 +84,15 @@ static INTERNODE_RPC_BODY_DIGEST_STRICT: LazyLock<bool> = LazyLock::new(|| {
         rustfs_config::DEFAULT_INTERNODE_RPC_BODY_DIGEST_STRICT,
     )
 });
-// Sized for peak legitimate body-bound mutation RPS x the retention window; overflow fails closed
-// and increments the replay-cache overflow counter. Clamped to at least 1 so a misconfigured zero
-// cannot disable replay protection by rejecting every body-bound request.
+static INTERNODE_RPC_REPLAY_SCOPE_STRICT: LazyLock<bool> = LazyLock::new(|| {
+    get_env_bool(
+        rustfs_config::ENV_INTERNODE_RPC_REPLAY_SCOPE_STRICT,
+        rustfs_config::DEFAULT_INTERNODE_RPC_REPLAY_SCOPE_STRICT,
+    )
+});
+// Sized for peak legitimate authenticated RPC RPS x the retention window once replay scope is
+// active; overflow fails closed and increments the replay-cache overflow counter. Clamped to at
+// least 1 so a misconfigured zero cannot disable replay protection by rejecting every request.
 static REPLAY_CACHE_CAPACITY: LazyLock<usize> = LazyLock::new(|| {
     rustfs_utils::get_env_usize(
         rustfs_config::ENV_INTERNODE_RPC_REPLAY_CACHE_CAPACITY,
@@ -86,6 +101,7 @@ static REPLAY_CACHE_CAPACITY: LazyLock<usize> = LazyLock::new(|| {
     .max(1)
 });
 static RPC_SECRET_RESOLUTION_LOG_ONCE: Once = Once::new();
+static RPC_BOOT_EPOCH: LazyLock<Uuid> = LazyLock::new(Uuid::new_v4);
 
 #[derive(Default)]
 struct RpcNonceCache {
@@ -313,6 +329,189 @@ fn verify_signature_v2(secret: &str, scope: SignatureV2Scope<'_>, signature: &st
     mac.verify_slice(&signature).is_ok()
 }
 
+#[derive(Clone, Copy)]
+struct ReplayScope<'a> {
+    audience: &'a str,
+    path: &'a str,
+    timestamp: &'a str,
+    nonce: Uuid,
+    content_sha256: &'a str,
+    boot_epoch: Uuid,
+}
+
+fn update_replay_scope(mac: &mut HmacSha256, scope: ReplayScope<'_>) {
+    mac.update(RPC_REPLAY_SCOPE_DOMAIN);
+    for part in [
+        scope.audience.as_bytes(),
+        b"|",
+        scope.path.as_bytes(),
+        b"|POST|",
+        scope.timestamp.as_bytes(),
+        b"|",
+        scope.nonce.as_bytes(),
+        b"|",
+        scope.content_sha256.as_bytes(),
+        b"|",
+        scope.boot_epoch.as_bytes(),
+    ] {
+        mac.update(part);
+    }
+}
+
+fn generate_replay_scope_signature(secret: &str, scope: ReplayScope<'_>) -> std::io::Result<String> {
+    let mut mac =
+        <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()).map_err(|_| std::io::Error::other("Invalid RPC HMAC key"))?;
+    update_replay_scope(&mut mac, scope);
+    Ok(general_purpose::STANDARD.encode(mac.finalize().into_bytes()))
+}
+
+fn verify_replay_scope_signature(secret: &str, scope: ReplayScope<'_>, signature: &str) -> bool {
+    let Ok(signature) = general_purpose::STANDARD.decode(signature) else {
+        return false;
+    };
+    let Ok(mut mac) = <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()) else {
+        return false;
+    };
+    update_replay_scope(&mut mac, scope);
+    mac.verify_slice(&signature).is_ok()
+}
+
+fn update_boot_epoch_proof(mac: &mut HmacSha256, audience: &str, challenge: Uuid, boot_epoch: Uuid) {
+    mac.update(RPC_BOOT_EPOCH_PROOF_DOMAIN);
+    mac.update(audience.as_bytes());
+    mac.update(b"|");
+    mac.update(challenge.as_bytes());
+    mac.update(boot_epoch.as_bytes());
+}
+
+fn generate_boot_epoch_proof(secret: &str, audience: &str, challenge: Uuid, boot_epoch: Uuid) -> std::io::Result<String> {
+    if audience.is_empty() || challenge.is_nil() || boot_epoch.is_nil() {
+        return Err(std::io::Error::other("Invalid RPC boot epoch proof scope"));
+    }
+    let mut mac =
+        <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()).map_err(|_| std::io::Error::other("Invalid RPC HMAC key"))?;
+    update_boot_epoch_proof(&mut mac, audience, challenge, boot_epoch);
+    Ok(general_purpose::STANDARD.encode(mac.finalize().into_bytes()))
+}
+
+fn verify_boot_epoch_proof(secret: &str, audience: &str, challenge: Uuid, boot_epoch: Uuid, proof: &str) -> std::io::Result<()> {
+    if audience.is_empty() || challenge.is_nil() || boot_epoch.is_nil() {
+        return Err(std::io::Error::other("Invalid RPC boot epoch proof scope"));
+    }
+    let proof = general_purpose::STANDARD
+        .decode(proof)
+        .map_err(|_| std::io::Error::other("Invalid RPC boot epoch proof"))?;
+    let mut mac =
+        <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()).map_err(|_| std::io::Error::other("Invalid RPC HMAC key"))?;
+    update_boot_epoch_proof(&mut mac, audience, challenge, boot_epoch);
+    mac.verify_slice(&proof)
+        .map_err(|_| std::io::Error::new(std::io::ErrorKind::PermissionDenied, "Invalid RPC boot epoch proof"))
+}
+
+fn non_nil_uuid(value: &str, name: &str) -> std::io::Result<Uuid> {
+    let value = Uuid::parse_str(value).map_err(|_| std::io::Error::other(format!("Invalid {name}")))?;
+    (!value.is_nil())
+        .then_some(value)
+        .ok_or_else(|| std::io::Error::other(format!("Invalid {name}")))
+}
+
+fn parse_tonic_rpc_path(path: &str) -> std::io::Result<(&str, &str)> {
+    path.strip_prefix('/')
+        .and_then(|path| path.split_once('/'))
+        .filter(|(service, rpc_method)| !service.is_empty() && !rpc_method.is_empty() && !rpc_method.contains('/'))
+        .ok_or_else(|| std::io::Error::other("Invalid RPC request path"))
+}
+
+/// The process-unique epoch included in every replay-scoped server verification.
+///
+/// A fresh process gets a fresh value, so a signature captured before a server restart cannot be
+/// admitted even though the bounded in-memory nonce cache necessarily starts empty again.
+pub fn tonic_rpc_boot_epoch() -> Uuid {
+    *RPC_BOOT_EPOCH
+}
+
+/// Build the additive replay-scope headers for a request that already carries rolling-upgrade-safe
+/// v1/v2 metadata. `timestamp` and `content_sha256` are deliberately reused from the v2 scope so
+/// old servers can continue validating the same request unchanged.
+pub fn gen_tonic_replay_scope_headers(
+    audience: &str,
+    path: &str,
+    timestamp: &str,
+    content_sha256: &str,
+    boot_epoch: Uuid,
+) -> std::io::Result<HeaderMap> {
+    if audience.is_empty() || !path.starts_with('/') || !valid_content_sha256(content_sha256) || boot_epoch.is_nil() {
+        return Err(std::io::Error::other("Invalid replay-scoped RPC signing scope"));
+    }
+    parse_tonic_rpc_path(path)?;
+    timestamp
+        .parse::<i64>()
+        .map_err(|_| std::io::Error::other("Invalid timestamp format"))?;
+
+    let nonce = Uuid::new_v4();
+    let signature = generate_replay_scope_signature(
+        &get_shared_secret()?,
+        ReplayScope {
+            audience,
+            path,
+            timestamp,
+            nonce,
+            content_sha256,
+            boot_epoch,
+        },
+    )?;
+    let mut headers = HeaderMap::new();
+    headers.insert(RPC_REPLAY_SCOPE_VERSION_HEADER, HeaderValue::from_static(RPC_REPLAY_SCOPE_VERSION_V3));
+    headers.insert(
+        RPC_REPLAY_SCOPE_SIGNATURE_HEADER,
+        header_value(&signature, RPC_REPLAY_SCOPE_SIGNATURE_HEADER)?,
+    );
+    headers.insert(
+        RPC_REPLAY_SCOPE_NONCE_HEADER,
+        header_value(&nonce.to_string(), RPC_REPLAY_SCOPE_NONCE_HEADER)?,
+    );
+    headers.insert(RPC_BOOT_EPOCH_HEADER, header_value(&boot_epoch.to_string(), RPC_BOOT_EPOCH_HEADER)?);
+    Ok(headers)
+}
+
+/// Parse the optional client challenge used to authenticate a server boot-epoch advertisement.
+pub fn tonic_boot_epoch_challenge(headers: &HeaderMap) -> std::io::Result<Option<Uuid>> {
+    headers
+        .get(RPC_BOOT_EPOCH_CHALLENGE_HEADER)
+        .map(|value| {
+            value
+                .to_str()
+                .map_err(|_| std::io::Error::other("Invalid RPC boot epoch challenge"))
+                .and_then(|value| non_nil_uuid(value, "RPC boot epoch challenge"))
+        })
+        .transpose()
+}
+
+/// Build the authenticated response headers for a client boot-epoch challenge.
+pub fn tonic_boot_epoch_response_headers(audience: &str, challenge: Uuid) -> std::io::Result<HeaderMap> {
+    let boot_epoch = tonic_rpc_boot_epoch();
+    let proof = generate_boot_epoch_proof(&get_shared_secret()?, audience, challenge, boot_epoch)?;
+    let mut headers = HeaderMap::new();
+    headers.insert(RPC_BOOT_EPOCH_HEADER, header_value(&boot_epoch.to_string(), RPC_BOOT_EPOCH_HEADER)?);
+    headers.insert(RPC_BOOT_EPOCH_PROOF_HEADER, header_value(&proof, RPC_BOOT_EPOCH_PROOF_HEADER)?);
+    Ok(headers)
+}
+
+/// Verify the server boot-epoch response for a challenge generated by this client.
+pub fn verify_tonic_boot_epoch_response(audience: &str, challenge: Uuid, headers: &HeaderMap) -> std::io::Result<Uuid> {
+    let boot_epoch = headers
+        .get(RPC_BOOT_EPOCH_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC boot epoch"))
+        .and_then(|value| non_nil_uuid(value, "RPC boot epoch"))?;
+    let proof = headers
+        .get(RPC_BOOT_EPOCH_PROOF_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC boot epoch proof"))?;
+    verify_boot_epoch_proof(&get_shared_secret()?, audience, challenge, boot_epoch, proof)?;
+    Ok(boot_epoch)
+}
+
 fn valid_content_sha256(value: &str) -> bool {
     value == UNSIGNED_PAYLOAD
         || (value.len() == 64
@@ -531,6 +730,17 @@ fn has_v2_auth_headers(headers: &HeaderMap) -> bool {
     .any(|name| headers.contains_key(*name))
 }
 
+fn has_replay_scope_headers(headers: &HeaderMap) -> bool {
+    [
+        RPC_REPLAY_SCOPE_VERSION_HEADER,
+        RPC_REPLAY_SCOPE_SIGNATURE_HEADER,
+        RPC_REPLAY_SCOPE_NONCE_HEADER,
+        RPC_BOOT_EPOCH_HEADER,
+    ]
+    .iter()
+    .any(|name| headers.contains_key(*name))
+}
+
 /// Whether the server requires target-bound v2 authentication on every internode gRPC request,
 /// rejecting the legacy constant-target fallback instead of accepting it. Default-off rollout
 /// lever gated on the v1-fallback counter reading zero fleet-wide; see
@@ -540,9 +750,127 @@ fn internode_rpc_signature_strict() -> bool {
     *INTERNODE_RPC_SIGNATURE_STRICT
 }
 
+fn internode_rpc_replay_scope_strict() -> bool {
+    *INTERNODE_RPC_REPLAY_SCOPE_STRICT
+}
+
+fn verify_tonic_replay_scope_signature(audience: &str, path: &str, headers: &HeaderMap) -> std::io::Result<()> {
+    if audience.is_empty() {
+        return Err(std::io::Error::other("Missing RPC audience"));
+    }
+    parse_tonic_rpc_path(path)?;
+
+    let version = headers
+        .get(RPC_REPLAY_SCOPE_VERSION_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC replay scope version"))?;
+    if version != RPC_REPLAY_SCOPE_VERSION_V3 {
+        return Err(std::io::Error::other("Unsupported RPC replay scope version"));
+    }
+    let signature = headers
+        .get(RPC_REPLAY_SCOPE_SIGNATURE_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC replay scope signature"))?;
+    let timestamp = headers
+        .get(TIMESTAMP_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing timestamp header"))?;
+    let signed_at = timestamp
+        .parse::<i64>()
+        .map_err(|_| std::io::Error::other("Invalid timestamp format"))?;
+    check_timestamp(signed_at)?;
+    let nonce = headers
+        .get(RPC_REPLAY_SCOPE_NONCE_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC replay scope nonce"))
+        .and_then(|value| non_nil_uuid(value, "RPC replay scope nonce"))?;
+    let content_sha256 = headers
+        .get(RPC_CONTENT_SHA256_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC content SHA-256"))?;
+    if !valid_content_sha256(content_sha256) {
+        return Err(std::io::Error::other("Invalid RPC content SHA-256"));
+    }
+    let boot_epoch = headers
+        .get(RPC_BOOT_EPOCH_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .ok_or_else(|| std::io::Error::other("Missing RPC boot epoch"))
+        .and_then(|value| non_nil_uuid(value, "RPC boot epoch"))?;
+    let secret = get_shared_secret()?;
+    if !verify_replay_scope_signature(
+        &secret,
+        ReplayScope {
+            audience,
+            path,
+            timestamp,
+            nonce,
+            content_sha256,
+            boot_epoch,
+        },
+        signature,
+    ) {
+        return Err(std::io::Error::other("Invalid RPC replay scope signature"));
+    }
+    if boot_epoch != tonic_rpc_boot_epoch() {
+        return Err(std::io::Error::other("RPC boot epoch is stale"));
+    }
+    check_and_record_nonce(nonce, signed_at)
+}
+
 /// Verify gRPC authentication, preferring v2 without downgrade on malformed v2 metadata.
 pub fn verify_tonic_rpc_signature(audience: &str, path: &str, headers: &HeaderMap) -> std::io::Result<()> {
-    verify_tonic_rpc_signature_with_strictness(audience, path, headers, internode_rpc_signature_strict())
+    verify_tonic_rpc_signature_with_policy(
+        audience,
+        path,
+        headers,
+        internode_rpc_signature_strict(),
+        internode_rpc_replay_scope_strict(),
+        false,
+    )
+}
+
+/// Verify gRPC authentication while allowing the narrowly scoped v2 `Ping` bootstrap used to
+/// obtain an authenticated server boot epoch when replay-scope strictness is enabled.
+pub fn verify_tonic_rpc_signature_with_bootstrap(
+    audience: &str,
+    path: &str,
+    headers: &HeaderMap,
+    allow_replay_scope_bootstrap: bool,
+) -> std::io::Result<()> {
+    verify_tonic_rpc_signature_with_policy(
+        audience,
+        path,
+        headers,
+        internode_rpc_signature_strict(),
+        internode_rpc_replay_scope_strict(),
+        allow_replay_scope_bootstrap,
+    )
+}
+
+fn verify_tonic_rpc_signature_with_policy(
+    audience: &str,
+    path: &str,
+    headers: &HeaderMap,
+    signature_strict: bool,
+    replay_scope_strict: bool,
+    allow_replay_scope_bootstrap: bool,
+) -> std::io::Result<()> {
+    if has_replay_scope_headers(headers) {
+        return verify_tonic_replay_scope_signature(audience, path, headers);
+    }
+
+    // Only a method-bound v2 Ping with a syntactically valid challenge may bootstrap a strict
+    // client after its peer restarts. Legacy metadata never gets this exception.
+    let bootstrap = allow_replay_scope_bootstrap
+        && has_v2_auth_headers(headers)
+        && tonic_boot_epoch_challenge(headers).is_ok_and(|challenge| challenge.is_some());
+    if replay_scope_strict && !bootstrap {
+        return Err(std::io::Error::other("RPC replay-scoped authentication required"));
+    }
+
+    verify_tonic_rpc_signature_with_strictness(audience, path, headers, signature_strict)?;
+    global_internode_metrics().record_replay_scope_fallback();
+    Ok(())
 }
 
 /// [`verify_tonic_rpc_signature`] with the strict gate injected as a parameter, so both rollout
@@ -1273,6 +1601,104 @@ mod tests {
         assert_eq!(error.to_string(), "Invalid RPC v2 signature");
     }
 
+    #[test]
+    fn replay_scope_binds_path_epoch_and_random_nonce() {
+        ensure_test_rpc_secret();
+        let path = "/node_service.NodeService/Ping";
+        let mut headers = gen_tonic_signature_headers("node-a:9000", "node_service.NodeService", "Ping", None)
+            .expect("v2 compatibility headers should build");
+        let timestamp = headers
+            .get(TIMESTAMP_HEADER)
+            .and_then(|value| value.to_str().ok())
+            .expect("v2 timestamp")
+            .to_string();
+        let content_sha256 = headers
+            .get(RPC_CONTENT_SHA256_HEADER)
+            .and_then(|value| value.to_str().ok())
+            .expect("v2 content digest")
+            .to_string();
+        headers.extend(
+            gen_tonic_replay_scope_headers("node-a:9000", path, &timestamp, &content_sha256, tonic_rpc_boot_epoch())
+                .expect("replay-scope headers should build"),
+        );
+
+        assert!(
+            verify_tonic_rpc_signature_with_policy("node-a:9000", path, &headers, false, false, false).is_ok(),
+            "the first replay-scoped request must be accepted"
+        );
+        let replay = verify_tonic_rpc_signature_with_policy("node-a:9000", path, &headers, false, false, false)
+            .expect_err("the random replay-scope nonce must be single-use");
+        assert_eq!(replay.to_string(), "RPC request replay detected");
+
+        let path_error = verify_tonic_replay_scope_signature("node-a:9000", "/node_service.NodeService/SignalService", &headers)
+            .expect_err("a replay-scoped signature must not move to another method");
+        assert_eq!(path_error.to_string(), "Invalid RPC replay scope signature");
+    }
+
+    #[test]
+    fn replay_scope_rejects_partial_metadata_and_stale_epoch_without_fallback() {
+        ensure_test_rpc_secret();
+        let path = "/node_service.NodeService/Ping";
+        let mut partial = gen_tonic_signature_headers("node-a:9000", "node_service.NodeService", "Ping", None)
+            .expect("v2 compatibility headers should build");
+        partial.insert(RPC_REPLAY_SCOPE_VERSION_HEADER, HeaderValue::from_static(RPC_REPLAY_SCOPE_VERSION_V3));
+        let error = verify_tonic_rpc_signature_with_policy("node-a:9000", path, &partial, false, false, false)
+            .expect_err("partial replay-scope metadata must never downgrade to v2");
+        assert_eq!(error.to_string(), "Missing RPC replay scope signature");
+
+        let timestamp = partial
+            .get(TIMESTAMP_HEADER)
+            .and_then(|value| value.to_str().ok())
+            .expect("v2 timestamp")
+            .to_string();
+        let content_sha256 = partial
+            .get(RPC_CONTENT_SHA256_HEADER)
+            .and_then(|value| value.to_str().ok())
+            .expect("v2 content digest")
+            .to_string();
+        let stale_epoch = Uuid::new_v4();
+        partial.extend(
+            gen_tonic_replay_scope_headers("node-a:9000", path, &timestamp, &content_sha256, stale_epoch)
+                .expect("replay-scope headers should build"),
+        );
+        let stale = verify_tonic_rpc_signature_with_policy("node-a:9000", path, &partial, false, false, false)
+            .expect_err("a signature from a prior server boot epoch must be rejected");
+        assert_eq!(stale.to_string(), "RPC boot epoch is stale");
+    }
+
+    #[test]
+    fn replay_scope_strictness_allows_only_authenticated_ping_bootstrap() {
+        ensure_test_rpc_secret();
+        let mut headers = gen_tonic_signature_headers("node-a:9000", "node_service.NodeService", "Ping", None)
+            .expect("v2 compatibility headers should build");
+        let rejected =
+            verify_tonic_rpc_signature_with_policy("node-a:9000", "/node_service.NodeService/Ping", &headers, false, true, false)
+                .expect_err("strict replay scope must reject stripped new metadata");
+        assert_eq!(rejected.to_string(), "RPC replay-scoped authentication required");
+
+        headers.insert(
+            RPC_BOOT_EPOCH_CHALLENGE_HEADER,
+            HeaderValue::from_str(&Uuid::new_v4().to_string()).expect("UUID header"),
+        );
+        assert!(
+            verify_tonic_rpc_signature_with_policy("node-a:9000", "/node_service.NodeService/Ping", &headers, false, true, true,)
+                .is_ok(),
+            "only the signed Ping bootstrap may obtain a new server epoch in strict mode"
+        );
+    }
+
+    #[test]
+    fn boot_epoch_response_proof_binds_audience_challenge_and_epoch() {
+        ensure_test_rpc_secret();
+        let challenge = Uuid::new_v4();
+        let headers = tonic_boot_epoch_response_headers("node-a:9000", challenge).expect("proof headers should build");
+        let epoch =
+            verify_tonic_boot_epoch_response("node-a:9000", challenge, &headers).expect("matching proof headers should verify");
+        assert_eq!(epoch, tonic_rpc_boot_epoch());
+        assert!(verify_tonic_boot_epoch_response("node-b:9000", challenge, &headers).is_err());
+        assert!(verify_tonic_boot_epoch_response("node-a:9000", Uuid::new_v4(), &headers).is_err());
+    }
+
     #[test]
     fn malformed_v2_auth_does_not_downgrade_to_valid_legacy_signature() {
         ensure_test_rpc_secret();

crates/ecstore/src/cluster/rpc/mod.rs

@@ -28,13 +28,18 @@ pub(crate) use background_monitor::pin_callsite_interest_for_test;
 pub use background_monitor::shutdown_background_monitors;
 pub(crate) use background_monitor::spawn_background_monitor;
 pub use client::{
-    TonicInterceptor, gen_tonic_signature_interceptor, node_service_time_out_client, node_service_time_out_client_no_auth,
+    AuthenticatedChannel, TonicInterceptor, gen_tonic_signature_interceptor, node_service_time_out_client,
+    node_service_time_out_client_no_auth,
 };
+// Re-exported through `api::rpc`; not every item is consumed inside this crate.
+#[allow(unused_imports)]
 pub use http_auth::{
-    TONIC_RPC_PREFIX, build_auth_headers, gen_signature_headers, gen_tonic_signature_headers, normalize_tonic_rpc_audience,
-    set_tonic_canonical_body_digest, set_tonic_mutation_body_digest, sign_ns_scanner_capability, sign_tonic_rpc_response_proof,
-    verify_ns_scanner_capability, verify_rpc_signature, verify_tonic_canonical_body_digest, verify_tonic_mutation_body_digest,
-    verify_tonic_rpc_response_proof, verify_tonic_rpc_signature,
+    TONIC_RPC_PREFIX, build_auth_headers, gen_signature_headers, gen_tonic_replay_scope_headers, gen_tonic_signature_headers,
+    normalize_tonic_rpc_audience, set_tonic_canonical_body_digest, set_tonic_mutation_body_digest, sign_ns_scanner_capability,
+    sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers, verify_ns_scanner_capability,
+    verify_rpc_signature, verify_tonic_boot_epoch_response, verify_tonic_canonical_body_digest,
+    verify_tonic_mutation_body_digest, verify_tonic_rpc_response_proof, verify_tonic_rpc_signature,
+    verify_tonic_rpc_signature_with_bootstrap,
 };
 #[cfg(test)]
 pub(crate) use internode_data_transport::TcpHttpInternodeDataTransport;

crates/ecstore/src/cluster/rpc/peer_rest_client.rs

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use crate::cluster::rpc::client::{
-    TonicInterceptor, embedded_tonic_status, gen_tonic_signature_interceptor, heal_control_time_out_client,
+    AuthenticatedChannel, TonicInterceptor, embedded_tonic_status, gen_tonic_signature_interceptor, heal_control_time_out_client,
     is_network_like_status, message_has_network_needle, node_service_time_out_client, tier_mutation_control_time_out_client,
 };
 use crate::cluster::rpc::{set_tonic_canonical_body_digest, set_tonic_mutation_body_digest, verify_tonic_rpc_response_proof};
@@ -66,7 +66,6 @@ use std::{
 use tokio::{net::TcpStream, time::Duration};
 use tonic::Request;
 use tonic::service::interceptor::InterceptedService;
-use tonic::transport::Channel;
 use tracing::{debug, info, warn};
 use uuid::Uuid;
 
@@ -412,7 +411,7 @@ impl PeerRestClient {
         (remote, all, remote_topology_hosts)
     }
 
-    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         if self.offline.load(Ordering::Acquire) {
             self.mark_offline_and_spawn_recovery();
             return Err(Error::other(format!("peer {} is temporarily offline", self.grid_host)));
@@ -433,7 +432,7 @@ impl PeerRestClient {
         &self,
     ) -> Result<
         rustfs_protos::proto_gen::node_service::heal_control_service_client::HealControlServiceClient<
-            InterceptedService<Channel, TonicInterceptor>,
+            InterceptedService<AuthenticatedChannel, TonicInterceptor>,
         >,
     > {
         if self.offline.load(Ordering::Acquire) {
@@ -454,7 +453,7 @@ impl PeerRestClient {
 
     async fn get_tier_mutation_control_client(
         &self,
-    ) -> Result<TierMutationControlServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    ) -> Result<TierMutationControlServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         if self.offline.load(Ordering::Acquire) {
             self.mark_offline_and_spawn_recovery();
             return Err(Error::other(format!("peer {} is temporarily offline", self.grid_host)));

crates/ecstore/src/cluster/rpc/peer_s3_client.rs

@@ -14,7 +14,8 @@
 
 use crate::bucket::metadata_sys;
 use crate::cluster::rpc::client::{
-    TonicInterceptor, gen_tonic_signature_interceptor, is_network_like_disk_error, node_service_time_out_client,
+    AuthenticatedChannel, TonicInterceptor, gen_tonic_signature_interceptor, is_network_like_disk_error,
+    node_service_time_out_client,
 };
 use crate::cluster::rpc::set_tonic_mutation_body_digest;
 use crate::disk::error::DiskError;
@@ -52,7 +53,6 @@ use tokio::{net::TcpStream, sync::RwLock, time};
 use tokio_util::sync::CancellationToken;
 use tonic::Request;
 use tonic::service::interceptor::InterceptedService;
-use tonic::transport::Channel;
 use tracing::{debug, info, warn};
 
 type Client = Arc<Box<dyn PeerS3Client>>;
@@ -832,7 +832,7 @@ impl RemotePeerS3Client {
         client
     }
 
-    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         node_service_time_out_client(&self.addr, TonicInterceptor::Signature(gen_tonic_signature_interceptor()))
             .await
             .map_err(|err| Error::other(format!("can not get client, err: {err}")))

crates/ecstore/src/cluster/rpc/remote_disk.rs

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 use crate::cluster::rpc::client::{
-    TonicInterceptor, gen_tonic_signature_interceptor, is_network_like_disk_error, node_service_time_out_client,
-    node_service_time_out_client_for_class, node_service_time_out_client_no_auth,
+    AuthenticatedChannel, TonicInterceptor, gen_tonic_signature_interceptor, is_network_like_disk_error,
+    node_service_time_out_client, node_service_time_out_client_for_class, node_service_time_out_client_no_auth,
 };
 use crate::cluster::rpc::http_auth::set_tonic_canonical_body_digest;
 use crate::cluster::rpc::internode_data_transport::{
@@ -71,7 +71,7 @@ use tokio::{
     time::timeout,
 };
 use tokio_util::sync::CancellationToken;
-use tonic::{Code, Request, service::interceptor::InterceptedService, transport::Channel};
+use tonic::{Code, Request, service::interceptor::InterceptedService};
 use tracing::{debug, trace, warn};
 use uuid::Uuid;
 
@@ -1083,7 +1083,7 @@ impl RemoteDisk {
         internode_offline_bypass_reason(&self.addr).map(Error::other)
     }
 
-    async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         if let Some(err) = self.offline_bypass_error() {
             return Err(err);
         }
@@ -1096,7 +1096,7 @@ impl RemoteDisk {
     /// Routes onto the isolated bulk channel pool so large transfers cannot head-of-line block
     /// lock/health RPCs (grpc-optimization P1). Falls back to the control channel when isolation
     /// is disabled.
-    async fn get_bulk_client(&self) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    async fn get_bulk_client(&self) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         if let Some(err) = self.offline_bypass_error() {
             return Err(err);
         }

crates/ecstore/src/cluster/rpc/remote_locker.rs

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::cluster::rpc::client::{TonicInterceptor, gen_tonic_signature_interceptor, node_service_time_out_client};
+use crate::cluster::rpc::client::{
+    AuthenticatedChannel, TonicInterceptor, gen_tonic_signature_interceptor, node_service_time_out_client,
+};
 use crate::cluster::rpc::set_tonic_mutation_body_digest;
 use async_trait::async_trait;
 use bytes::Bytes;
@@ -29,7 +31,6 @@ use std::time::Duration;
 use tokio::time::timeout;
 use tonic::Request;
 use tonic::service::interceptor::InterceptedService;
-use tonic::transport::Channel;
 use tracing::{debug, info, warn};
 
 /// Remote lock client implementation
@@ -78,7 +79,7 @@ impl RemoteClient {
         }
     }
 
-    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<Channel, TonicInterceptor>>> {
+    pub async fn get_client(&self) -> Result<NodeServiceClient<InterceptedService<AuthenticatedChannel, TonicInterceptor>>> {
         // P3-2 offline bypass (now covering the lock path too): fast-fail a peer already marked
         // offline instead of paying the connect timeout, so dsync reaches quorum sooner. Does not
         // change quorum; the self-healing re-probe keeps the peer recoverable.

crates/io-metrics/src/internode_metrics.rs

@@ -67,6 +67,7 @@ const INTERNODE_MSGPACK_JSON_FALLBACK_TOTAL: &str = "rustfs_system_network_inter
 const INTERNODE_MSGPACK_JSON_DECODE_ERROR_TOTAL: &str = "rustfs_system_network_internode_msgpack_json_decode_error_total";
 const INTERNODE_SIGNATURE_V1_FALLBACK_TOTAL: &str = "rustfs_system_network_internode_signature_v1_fallback_total";
 const INTERNODE_BODY_DIGEST_FALLBACK_TOTAL: &str = "rustfs_system_network_internode_body_digest_fallback_total";
+const INTERNODE_REPLAY_SCOPE_FALLBACK_TOTAL: &str = "rustfs_system_network_internode_replay_scope_fallback_total";
 const INTERNODE_REPLAY_CACHE_OVERFLOW_TOTAL: &str = "rustfs_system_network_internode_replay_cache_overflow_total";
 const ERASURE_WRITE_QUORUM_FAILURES_TOTAL: &str = "rustfs_system_storage_erasure_write_quorum_failures_total";
 
@@ -159,6 +160,7 @@ pub struct InternodeMetricsSnapshot {
     pub operation_write_shutdown_errors_total: u64,
     pub signature_v1_fallback_total: u64,
     pub body_digest_fallback_total: u64,
+    pub replay_scope_fallback_total: u64,
     pub replay_cache_overflow_total: u64,
 }
 
@@ -180,6 +182,7 @@ pub struct InternodeMetrics {
     msgpack_json_decode_error_total: AtomicU64,
     signature_v1_fallback_total: AtomicU64,
     body_digest_fallback_total: AtomicU64,
+    replay_scope_fallback_total: AtomicU64,
     replay_cache_overflow_total: AtomicU64,
 }
 
@@ -431,6 +434,13 @@ impl InternodeMetrics {
         counter!(INTERNODE_BODY_DIGEST_FALLBACK_TOTAL).increment(1);
     }
 
+    /// Count an accepted v1/v2 request that does not carry the replay-scoped signature. This is
+    /// the convergence signal for `RUSTFS_INTERNODE_RPC_REPLAY_SCOPE_STRICT`.
+    pub fn record_replay_scope_fallback(&self) {
+        self.replay_scope_fallback_total.fetch_add(1, Ordering::Relaxed);
+        counter!(INTERNODE_REPLAY_SCOPE_FALLBACK_TOTAL).increment(1);
+    }
+
     /// Count a body-bound internode RPC rejected because the replay-protection nonce cache was
     /// full. Overflow fails closed, so a sustained non-zero rate means
     /// `RUSTFS_INTERNODE_RPC_REPLAY_CACHE_CAPACITY` is undersized for this node's peak legitimate
@@ -488,6 +498,7 @@ impl InternodeMetrics {
             operation_write_shutdown_errors_total: self.operation_write_shutdown_errors_total.load(Ordering::Relaxed),
             signature_v1_fallback_total: self.signature_v1_fallback_total.load(Ordering::Relaxed),
             body_digest_fallback_total: self.body_digest_fallback_total.load(Ordering::Relaxed),
+            replay_scope_fallback_total: self.replay_scope_fallback_total.load(Ordering::Relaxed),
             replay_cache_overflow_total: self.replay_cache_overflow_total.load(Ordering::Relaxed),
         }
     }
@@ -510,6 +521,7 @@ impl InternodeMetrics {
         self.msgpack_json_decode_error_total.store(0, Ordering::Relaxed);
         self.signature_v1_fallback_total.store(0, Ordering::Relaxed);
         self.body_digest_fallback_total.store(0, Ordering::Relaxed);
+        self.replay_scope_fallback_total.store(0, Ordering::Relaxed);
         self.replay_cache_overflow_total.store(0, Ordering::Relaxed);
     }
 }
@@ -887,6 +899,19 @@ mod tests {
         assert_eq!(metrics.snapshot().signature_v1_fallback_total, 0);
     }
 
+    #[test]
+    fn replay_scope_fallback_counter_updates_snapshot_and_resets() {
+        let metrics = InternodeMetrics::default();
+        assert_eq!(metrics.snapshot().replay_scope_fallback_total, 0);
+
+        metrics.record_replay_scope_fallback();
+        metrics.record_replay_scope_fallback();
+        assert_eq!(metrics.snapshot().replay_scope_fallback_total, 2);
+
+        metrics.reset_for_test();
+        assert_eq!(metrics.snapshot().replay_scope_fallback_total, 0);
+    }
+
     #[test]
     fn cluster_peer_flips_offline_after_threshold_and_back_online() {
         // Unique addr keeps this independent of the process-global registry / other tests.

rustfs/src/server/http.rs

@@ -37,7 +37,8 @@ use crate::storage_api::server::http as storage;
 use crate::storage_api::server::http::rpc::InternodeRpcService;
 use crate::storage_api::server::http::tonic_service::make_server;
 use crate::storage_api::server::http::{
-    ServerContextSlot, TONIC_RPC_PREFIX, normalize_tonic_rpc_audience, verify_tonic_rpc_signature,
+    ServerContextSlot, TONIC_RPC_PREFIX, normalize_tonic_rpc_audience, tonic_boot_epoch_challenge,
+    tonic_boot_epoch_response_headers, verify_tonic_rpc_signature_with_bootstrap,
 };
 use bytes::Bytes;
 use http::{HeaderMap, Method, Request as HttpRequest, Response, Uri};
@@ -152,13 +153,17 @@ impl<S> RpcRequestPathService<S> {
     }
 }
 
-impl<S, B> Service<HttpRequest<B>> for RpcRequestPathService<S>
+impl<S, B, ResBody> Service<HttpRequest<B>> for RpcRequestPathService<S>
 where
-    S: Service<HttpRequest<B>>,
+    S: Service<HttpRequest<B>, Response = Response<ResBody>>,
+    S::Error: Send + 'static,
+    S::Future: Send + 'static,
+    B: Send + 'static,
+    ResBody: Send + 'static,
 {
-    type Response = S::Response;
+    type Response = Response<ResBody>;
     type Error = S::Error;
-    type Future = S::Future;
+    type Future = Pin<Box<dyn Future<Output = std::result::Result<Self::Response, Self::Error>> + Send>>;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<std::result::Result<(), Self::Error>> {
         self.inner.poll_ready(cx)
@@ -170,7 +175,22 @@ where
             method: req.method().clone(),
         };
         req.extensions_mut().insert(target);
-        self.inner.call(req)
+        let response_headers = tonic_boot_epoch_challenge(req.headers())
+            .ok()
+            .flatten()
+            .and_then(|challenge| {
+                storage::try_current_local_node_name()
+                    .and_then(|node| normalize_tonic_rpc_audience(&node).ok())
+                    .and_then(|audience| tonic_boot_epoch_response_headers(&audience, challenge).ok())
+            });
+        let future = self.inner.call(req);
+        Box::pin(async move {
+            let mut response = future.await?;
+            if let Some(headers) = response_headers {
+                response.headers_mut().extend(headers);
+            }
+            Ok(response)
+        })
     }
 }
 
@@ -1862,7 +1882,15 @@ fn check_auth(req: Request<()>) -> std::result::Result<Request<()>, Status> {
         .filter(|method| !method.is_empty() && !method.contains('/'))
         .ok_or_else(|| Status::unauthenticated("Invalid RPC request path"))?;
     debug_assert!(!rpc_method.is_empty());
-    verify_tonic_rpc_signature(&audience, target.uri.path(), req.metadata().as_ref()).map_err(|e| {
+    let allow_replay_scope_bootstrap = target.uri.path() == "/node_service.NodeService/Ping"
+        && tonic_boot_epoch_challenge(req.metadata().as_ref()).is_ok_and(|challenge| challenge.is_some());
+    verify_tonic_rpc_signature_with_bootstrap(
+        &audience,
+        target.uri.path(),
+        req.metadata().as_ref(),
+        allow_replay_scope_bootstrap,
+    )
+    .map_err(|e| {
         error!(
             event = EVENT_RPC_SIGNATURE_VERIFICATION_FAILED,
             component = LOG_COMPONENT_SERVER,

rustfs/src/storage/storage_api.rs

@@ -495,8 +495,9 @@ pub(crate) mod ecstore_rpc {
     pub(crate) use rustfs_ecstore::api::rpc::{
         LocalPeerS3Client, PEER_RESTDRY_RUN, PEER_RESTSIGNAL, PEER_RESTSUB_SYS, PeerRestClient, PeerS3Client,
         SERVICE_SIGNAL_REFRESH_CONFIG, SERVICE_SIGNAL_RELOAD_DYNAMIC, TONIC_RPC_PREFIX, normalize_tonic_rpc_audience,
-        sign_ns_scanner_capability, sign_tonic_rpc_response_proof, verify_rpc_signature, verify_tonic_canonical_body_digest,
-        verify_tonic_mutation_body_digest, verify_tonic_rpc_signature,
+        sign_ns_scanner_capability, sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers,
+        verify_rpc_signature, verify_tonic_canonical_body_digest, verify_tonic_mutation_body_digest,
+        verify_tonic_rpc_signature_with_bootstrap,
     };
     #[cfg(test)]
     pub(crate) use rustfs_ecstore::api::rpc::{
@@ -1605,8 +1606,21 @@ pub(crate) fn sign_ns_scanner_capability(challenge: uuid::Uuid, server_epoch: uu
     ecstore_rpc::sign_ns_scanner_capability(challenge, server_epoch)
 }
 
-pub(crate) fn verify_tonic_rpc_signature(audience: &str, path: &str, headers: &http::HeaderMap) -> std::io::Result<()> {
-    ecstore_rpc::verify_tonic_rpc_signature(audience, path, headers)
+pub(crate) fn verify_tonic_rpc_signature_with_bootstrap(
+    audience: &str,
+    path: &str,
+    headers: &http::HeaderMap,
+    allow_replay_scope_bootstrap: bool,
+) -> std::io::Result<()> {
+    ecstore_rpc::verify_tonic_rpc_signature_with_bootstrap(audience, path, headers, allow_replay_scope_bootstrap)
+}
+
+pub(crate) fn tonic_boot_epoch_challenge(headers: &http::HeaderMap) -> std::io::Result<Option<uuid::Uuid>> {
+    ecstore_rpc::tonic_boot_epoch_challenge(headers)
+}
+
+pub(crate) fn tonic_boot_epoch_response_headers(audience: &str, challenge: uuid::Uuid) -> std::io::Result<http::HeaderMap> {
+    ecstore_rpc::tonic_boot_epoch_response_headers(audience, challenge)
 }
 
 pub(crate) fn verify_tonic_canonical_body_digest<T>(request: &tonic::Request<T>, canonical_body: &[u8]) -> std::io::Result<()> {

rustfs/src/storage_api.rs

@@ -97,7 +97,8 @@ pub(crate) mod server {
 
     pub(crate) mod http {
         pub(crate) use crate::storage::storage_api::{
-            ServerContextSlot, TONIC_RPC_PREFIX, normalize_tonic_rpc_audience, verify_tonic_rpc_signature,
+            ServerContextSlot, TONIC_RPC_PREFIX, normalize_tonic_rpc_audience, tonic_boot_epoch_challenge,
+            tonic_boot_epoch_response_headers, verify_tonic_rpc_signature_with_bootstrap,
         };
 
         pub(crate) fn try_current_local_node_name() -> Option<String> {