openrtc/

offline.rs

//! Offline device enrollment, trust bundles, and generation-bound proof.
//!
//! Discovery remains deliberately untrusted. LAN, BLE, QR, and USB adapters
//! may report candidates, but only these signed facts can authorize an offline
//! device. The normal `Client` peer-session actor remains the sole owner of
//! dialing, transport generations, and application-route readiness.

use std::collections::{BTreeMap, BTreeSet, VecDeque};
#[cfg(not(target_arch = "wasm32"))]
use std::path::{Path, PathBuf};
#[cfg(not(target_arch = "wasm32"))]
use std::sync::{Arc, Mutex};

use anyhow::{anyhow, ensure, Context, Result};
use base64::{engine::general_purpose::URL_SAFE_NO_PAD, Engine as _};
use ed25519_dalek::{Signature, Signer as _, SigningKey, Verifier as _, VerifyingKey};
use serde::{Deserialize, Serialize};
use sha2::{Digest as _, Sha256};

pub const OFFLINE_DEVICE_PROTOCOL: &str = "openrtc-offline-device/1";
pub const OFFLINE_PROOF_PROTOCOL: &str = "openrtc-offline-proof/1";
pub const OFFLINE_TRUST_BUNDLE_PROTOCOL: &str = "openrtc-offline-trust-bundle/1";
pub const MAX_OFFLINE_ROLES: usize = 32;
pub const MAX_OFFLINE_CREDENTIALS: usize = 256;
pub const MAX_OFFLINE_REVOKED_SERIALS: usize = 1_024;
pub const MAX_OFFLINE_SWARM_MEMBERS: usize = 100;
pub const MAX_OFFLINE_SWARM_DEGREE: usize = 5;
pub const MAX_OFFLINE_REPLAY_ENTRIES: usize = 4_096;
pub const MAX_OFFLINE_TRUST_HISTORY: usize = 128;
#[cfg(not(target_arch = "wasm32"))]
const MAX_OFFLINE_TRUST_JOURNAL_BYTES: u64 = 8 * 1024 * 1024;
#[cfg(not(target_arch = "wasm32"))]
const OFFLINE_TRUST_JOURNAL_PROTOCOL: &str = "openrtc-offline-trust-journal/1";

#[cfg(not(target_arch = "wasm32"))]
pub struct OfflineClient<'a> {
    client: &'a crate::Client,
}

#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone)]
pub struct OfflineEnrollmentOptions {
    pub trust_domain: String,
    pub device_id: String,
    pub enrollment_nonce: String,
    pub requested_roles: Vec<String>,
    pub requested_assurance: OfflineAssurance,
    pub created_at_ms: u64,
}

/// Native-only runtime inputs retained by the Rust owner while offline LAN
/// discovery and admission are enabled.
///
/// The signer keeps private-key custody in the host. The durable trust state
/// owns signed fleet policy, rollback protection, and the accepted-proof replay
/// window. Neither value is projected to TypeScript.
#[cfg(not(target_arch = "wasm32"))]
pub struct OfflineRuntimeConfig {
    pub local_device_id: String,
    pub signer: Arc<dyn OfflineSigner>,
    pub trust: Arc<Mutex<DurableOfflineTrustState>>,
}

#[cfg(not(target_arch = "wasm32"))]
#[derive(Clone)]
pub(crate) struct InstalledOfflineRuntime {
    pub(crate) local_device_id: String,
    pub(crate) signer: Arc<dyn OfflineSigner>,
    pub(crate) trust: Arc<Mutex<DurableOfflineTrustState>>,
    pub(crate) desired_revision: u64,
    pub(crate) candidates: BTreeMap<String, OfflineDesiredCandidate>,
}

#[cfg(not(target_arch = "wasm32"))]
#[derive(Clone)]
pub(crate) struct OfflineDesiredCandidate {
    pub(crate) handoff: OfflineCandidateHandoff,
    pub(crate) endpoint_addr: iroh::EndpointAddr,
    pub(crate) reachable: bool,
}

#[cfg(not(target_arch = "wasm32"))]
impl<'a> OfflineClient<'a> {
    pub(crate) fn new(client: &'a crate::Client) -> Self {
        Self { client }
    }

    /// Create a request bound to the one native Iroh endpoint owned by this
    /// client. The caller-supplied signer retains all private-key custody.
    pub async fn create_enrollment_request(
        &self,
        signer: &dyn OfflineSigner,
        options: OfflineEnrollmentOptions,
    ) -> Result<OfflineEnrollmentRequest> {
        let endpoint_id =
            self.client.current_node_id().await.ok_or_else(|| {
                anyhow!("Iroh endpoint must be started before offline enrollment")
            })?;
        OfflineEnrollmentRequest::create(
            signer,
            &options.trust_domain,
            &options.device_id,
            &endpoint_id,
            &options.enrollment_nonce,
            options.requested_roles,
            options.requested_assurance,
            options.created_at_ms,
        )
    }

    pub async fn network_policy(&self) -> crate::client::NetworkPolicy {
        self.client.transport_config().await.network_policy
    }

    /// Install the native offline trust owner and feed any already-observed
    /// local candidates into the existing desired-peer actor.
    pub async fn install_runtime(&self, config: OfflineRuntimeConfig) -> Result<()> {
        self.client.install_offline_runtime(config).await
    }

    /// Apply one signed trust update and immediately retire credentials that
    /// disappeared, were revoked, or changed endpoint identity.
    pub async fn apply_trust_bundle(
        &self,
        bundle: OfflineTrustBundle,
        at_ms: u64,
    ) -> Result<OfflineTrustHighWater> {
        self.client.apply_offline_trust_bundle(bundle, at_ms).await
    }

    /// Explicitly retire the old endpoint before a device rotates endpoint or
    /// proof-key identity. A later local observation must pass current trust and
    /// complete a fresh proof before product traffic resumes.
    pub async fn retire_device(&self, device_id: &str) -> Result<bool> {
        self.client.retire_offline_device(device_id).await
    }

    /// Register trust-validated local intent with the existing admission
    /// owner. This does not dial or start a retry loop.
    pub async fn register_candidate(&self, candidate: OfflineCandidateHandoff) -> Result<String> {
        self.client
            .register_offline_candidate_requirement(candidate)
            .await
            .map_err(anyhow::Error::msg)
    }

    /// Commit a fresh proof only if its exact physical generation is current.
    pub async fn commit_admission(&self, handoff: OfflineAdmissionHandoff) -> Result<String> {
        self.client
            .commit_offline_admission_handoff(handoff)
            .await
            .map_err(anyhow::Error::msg)
    }

    #[cfg(feature = "transport-lan")]
    pub async fn observed_lan_peers(&self) -> Vec<crate::local_discovery::LocalPeerSnapshot> {
        self.client.list_local_peers().await
    }
}

#[cfg(not(target_arch = "wasm32"))]
fn offline_desired_peers_json(
    candidates: &BTreeMap<String, OfflineDesiredCandidate>,
) -> Result<String> {
    let peers = candidates
        .values()
        .filter(|candidate| candidate.reachable)
        .map(|candidate| {
            serde_json::json!({
                "deviceId": candidate.handoff.device_id(),
                "nodeId": candidate.endpoint_addr.id.to_string(),
                "ticket": iroh_tickets::endpoint::EndpointTicket::new(
                    candidate.endpoint_addr.clone()
                ).to_string(),
                "online": true,
            })
        })
        .collect::<Vec<_>>();
    serde_json::to_string(&peers).context("encode offline desired peers")
}

#[cfg(not(target_arch = "wasm32"))]
impl crate::Client {
    pub(crate) async fn offline_runtime_is_installed(&self) -> bool {
        self.offline_runtime.lock().await.is_some()
    }

    pub(crate) async fn offline_candidate_is_reachable(
        &self,
        candidate: &OfflineCandidateHandoff,
    ) -> bool {
        self.offline_runtime
            .lock()
            .await
            .as_ref()
            .and_then(|runtime| runtime.candidates.get(candidate.device_id()))
            .is_some_and(|current| current.reachable && current.handoff.same_authority(candidate))
    }

    pub(crate) async fn install_offline_runtime(&self, config: OfflineRuntimeConfig) -> Result<()> {
        ensure!(
            self.transport_config().await.network_policy == crate::client::NetworkPolicy::LocalOnly,
            "offline runtime requires the LocalOnly network policy"
        );
        let local_device_id = required(&config.local_device_id, "local device id", 192)?;
        let local_endpoint_id = self
            .current_node_id()
            .await
            .ok_or_else(|| anyhow!("Iroh endpoint must be started before offline runtime"))?;
        let at_ms = crate::coordination::now_millis_u64();
        let mut runtime_guard = self.offline_runtime.lock().await;
        let trust_domain = {
            let trust = config
                .trust
                .lock()
                .map_err(|_| anyhow!("offline trust state lock poisoned"))?;
            let credential = trust.trust().credential(&local_device_id, at_ms)?;
            ensure!(
                credential.body.endpoint_id == local_endpoint_id,
                "local offline credential is bound to a different Iroh endpoint"
            );
            ensure!(
                public_key(&credential.body.proof_public_key)? == config.signer.verifying_key()?,
                "offline signer does not match the local credential"
            );
            credential.body.trust_domain.clone()
        };
        if let Some(current) = runtime_guard.as_ref() {
            if current.local_device_id == local_device_id
                && Arc::ptr_eq(&current.signer, &config.signer)
                && Arc::ptr_eq(&current.trust, &config.trust)
            {
                ensure!(
                    self.native_external_auto_connect_owner_is_current(
                        &format!("offline:{trust_domain}"),
                        &local_device_id,
                    )
                    .await,
                    "offline runtime owner is no longer current; explicit Rust-owned retirement is required"
                );
                return Ok(());
            }
            return Err(anyhow!(
                "offline runtime is already installed; replacement requires an explicit Rust-owned retirement transaction"
            ));
        }

        std::sync::Arc::new(self.clone())
            .start_external_auto_connect(format!("offline:{trust_domain}"), local_device_id.clone())
            .await?;
        *runtime_guard = Some(InstalledOfflineRuntime {
            local_device_id,
            signer: config.signer,
            trust: config.trust,
            desired_revision: 0,
            candidates: BTreeMap::new(),
        });
        drop(runtime_guard);

        #[cfg(feature = "transport-lan")]
        for endpoint_addr in self.local_discovery_registry.endpoint_addrs().await {
            // A stale/untrusted observation does not prevent the owner from
            // installing; it simply never becomes desired-peer input.
            let _ = self.observe_offline_lan_candidate(endpoint_addr).await;
        }
        Ok(())
    }

    #[cfg(feature = "transport-lan")]
    pub(crate) async fn observe_offline_lan_candidate(
        &self,
        endpoint_addr: iroh::EndpointAddr,
    ) -> Result<bool> {
        ensure!(
            self.transport_config().await.network_policy == crate::client::NetworkPolicy::LocalOnly,
            "offline LAN observations require the LocalOnly network policy"
        );
        let at_ms = crate::coordination::now_millis_u64();
        let trust = self
            .offline_runtime
            .lock()
            .await
            .as_ref()
            .map(|runtime| runtime.trust.clone())
            .ok_or_else(|| anyhow!("offline runtime is not installed"))?;
        let device_id = {
            let trust = trust
                .lock()
                .map_err(|_| anyhow!("offline trust state lock poisoned"))?;
            trust
                .trust()
                .device_id_for_endpoint(&endpoint_addr.id.to_string(), at_ms)?
        };
        let handoff = {
            let trust = trust
                .lock()
                .map_err(|_| anyhow!("offline trust state lock poisoned"))?;
            trust
                .trust()
                .authorize_local_candidate(&device_id, endpoint_addr.clone(), at_ms)?
        };
        self.register_offline_candidate_requirement(handoff.clone())
            .await
            .map_err(anyhow::Error::msg)?;

        let (revision, peers_json, changed) = {
            let mut guard = self.offline_runtime.lock().await;
            let runtime = guard
                .as_mut()
                .ok_or_else(|| anyhow!("offline runtime was removed"))?;
            let ticket =
                iroh_tickets::endpoint::EndpointTicket::new(endpoint_addr.clone()).to_string();
            let changed = runtime
                .candidates
                .get(&device_id)
                .map(|current| {
                    iroh_tickets::endpoint::EndpointTicket::new(current.endpoint_addr.clone())
                        .to_string()
                        != ticket
                        || !current.handoff.same_authority(&handoff)
                        || !current.reachable
                })
                .unwrap_or(true);
            if !changed {
                return Ok(false);
            }
            runtime.candidates.insert(
                device_id,
                OfflineDesiredCandidate {
                    handoff,
                    endpoint_addr,
                    reachable: true,
                },
            );
            runtime.desired_revision = runtime.desired_revision.saturating_add(1).max(1);
            (
                runtime.desired_revision,
                offline_desired_peers_json(&runtime.candidates)?,
                changed,
            )
        };
        let _ = std::sync::Arc::new(self.clone())
            .submit_external_desired_peers(revision, &peers_json)
            .await?;
        Ok(changed)
    }

    /// Remove one expired local observation from dial eligibility while
    /// retaining its signed credential and any healthy admitted route. This is
    /// reachability input, not revocation or a transport-close command.
    #[cfg(feature = "transport-lan")]
    pub(crate) async fn expire_offline_lan_candidate(
        &self,
        endpoint_id: iroh::EndpointId,
    ) -> Result<bool> {
        let (device_id, revision, peers_json) = {
            let mut guard = self.offline_runtime.lock().await;
            let runtime = guard
                .as_mut()
                .ok_or_else(|| anyhow!("offline runtime is not installed"))?;
            let Some((device_id, candidate)) = runtime
                .candidates
                .iter_mut()
                .find(|(_, candidate)| candidate.endpoint_addr.id == endpoint_id)
            else {
                return Ok(false);
            };
            if !candidate.reachable {
                return Ok(false);
            }
            candidate.reachable = false;
            let device_id = device_id.clone();
            runtime.desired_revision = runtime.desired_revision.saturating_add(1).max(1);
            (
                device_id,
                runtime.desired_revision,
                offline_desired_peers_json(&runtime.candidates)?,
            )
        };
        if let Some(local_endpoint_id) = self.current_node_id().await {
            let connection_id =
                Self::deterministic_connection_id(&local_endpoint_id, &endpoint_id.to_string());
            self.offline_proof_attempts
                .lock()
                .await
                .remove(&connection_id);
        }
        let _ = std::sync::Arc::new(self.clone())
            .submit_external_desired_peer_observation_expired(revision, &peers_json, &device_id)
            .await?;
        Ok(true)
    }

    pub(crate) async fn retire_offline_device(&self, device_id: &str) -> Result<bool> {
        let device_id = required(device_id, "offline device id", 192)?;
        let (removed, revision, peers_json, node_id) = {
            let mut guard = self.offline_runtime.lock().await;
            let runtime = guard
                .as_mut()
                .ok_or_else(|| anyhow!("offline runtime is not installed"))?;
            let removed = runtime.candidates.remove(&device_id);
            let Some(removed) = removed else {
                return Ok(false);
            };
            runtime.desired_revision = runtime.desired_revision.saturating_add(1).max(1);
            (
                removed.handoff,
                runtime.desired_revision,
                offline_desired_peers_json(&runtime.candidates)?,
                removed.endpoint_addr.id.to_string(),
            )
        };
        self.retire_offline_candidate_requirement(&removed).await;
        let _ = std::sync::Arc::new(self.clone())
            .submit_external_desired_peers(revision, &peers_json)
            .await?;
        self.retire_offline_desired_route(&device_id, Some(&node_id))
            .await;
        Ok(true)
    }

    pub(crate) async fn apply_offline_trust_bundle(
        &self,
        bundle: OfflineTrustBundle,
        at_ms: u64,
    ) -> Result<OfflineTrustHighWater> {
        let (trust, candidates) = {
            let guard = self.offline_runtime.lock().await;
            let runtime = guard
                .as_ref()
                .ok_or_else(|| anyhow!("offline runtime is not installed"))?;
            (runtime.trust.clone(), runtime.candidates.clone())
        };
        let prior = {
            let trust = trust
                .lock()
                .map_err(|_| anyhow!("offline trust state lock poisoned"))?;
            candidates
                .keys()
                .filter_map(|device_id| {
                    trust
                        .trust()
                        .credential(device_id, at_ms)
                        .ok()
                        .map(|credential| (device_id.clone(), credential.clone()))
                })
                .collect::<BTreeMap<_, _>>()
        };
        let high_water = trust
            .lock()
            .map_err(|_| anyhow!("offline trust state lock poisoned"))?
            .apply(bundle, at_ms)?;

        let mut retire = Vec::new();
        for (device_id, candidate) in &candidates {
            let next = trust
                .lock()
                .map_err(|_| anyhow!("offline trust state lock poisoned"))?
                .trust()
                .credential(device_id, at_ms)
                .cloned();
            let changed_identity = match (prior.get(device_id), next.as_ref().ok()) {
                (Some(previous), Some(current)) => {
                    previous.body.serial != current.body.serial
                        || previous.body.endpoint_id != current.body.endpoint_id
                        || previous.body.proof_public_key != current.body.proof_public_key
                }
                _ => true,
            };
            if changed_identity {
                retire.push(device_id.clone());
            } else {
                #[cfg(feature = "transport-lan")]
                {
                    // Same device/key under a newer signed bundle: refresh the
                    // requirement and require a new proof without turning an
                    // expired observation back into dial eligibility.
                    let refreshed = trust
                        .lock()
                        .map_err(|_| anyhow!("offline trust state lock poisoned"))?
                        .trust()
                        .authorize_local_candidate(
                            device_id,
                            candidate.endpoint_addr.clone(),
                            at_ms,
                        )?;
                    self.register_offline_candidate_requirement(refreshed.clone())
                        .await
                        .map_err(anyhow::Error::msg)?;
                    let (revision, peers_json) = {
                        let mut guard = self.offline_runtime.lock().await;
                        let runtime = guard
                            .as_mut()
                            .ok_or_else(|| anyhow!("offline runtime was removed"))?;
                        let current = runtime
                            .candidates
                            .get_mut(device_id)
                            .ok_or_else(|| anyhow!("offline candidate disappeared"))?;
                        current.handoff = refreshed;
                        runtime.desired_revision =
                            runtime.desired_revision.saturating_add(1).max(1);
                        (
                            runtime.desired_revision,
                            offline_desired_peers_json(&runtime.candidates)?,
                        )
                    };
                    let _ = std::sync::Arc::new(self.clone())
                        .submit_external_desired_peers(revision, &peers_json)
                        .await?;
                }
                #[cfg(not(feature = "transport-lan"))]
                let _ = (device_id, candidate);
            }
        }
        for device_id in retire {
            self.retire_offline_device(&device_id).await?;
        }
        Ok(high_water)
    }
}

fn required(value: &str, label: &str, max: usize) -> Result<String> {
    let value = value.trim();
    ensure!(!value.is_empty(), "{label} is required");
    ensure!(value.len() <= max, "{label} exceeds {max} bytes");
    ensure!(
        !value.chars().any(char::is_control),
        "{label} contains control characters"
    );
    Ok(value.to_string())
}

fn canonical_bytes<T: Serialize>(domain: &str, value: &T) -> Result<Vec<u8>> {
    let mut out = Vec::with_capacity(256);
    out.extend_from_slice(domain.as_bytes());
    out.push(0);
    out.extend_from_slice(&serde_json::to_vec(value).context("encode signed offline payload")?);
    Ok(out)
}

fn public_key(value: &str) -> Result<VerifyingKey> {
    let bytes = URL_SAFE_NO_PAD
        .decode(value)
        .context("decode Ed25519 public key")?;
    let bytes: [u8; 32] = bytes
        .try_into()
        .map_err(|_| anyhow!("Ed25519 public key must contain 32 bytes"))?;
    VerifyingKey::from_bytes(&bytes).context("parse Ed25519 public key")
}

fn signature(value: &str) -> Result<Signature> {
    let bytes = URL_SAFE_NO_PAD
        .decode(value)
        .context("decode Ed25519 signature")?;
    Signature::from_slice(&bytes).context("parse Ed25519 signature")
}

fn key_id(key: &VerifyingKey) -> String {
    format!(
        "ed25519:{}",
        hex::encode(&Sha256::digest(key.as_bytes())[..12])
    )
}

fn digest_json<T: Serialize>(value: &T) -> Result<String> {
    Ok(hex::encode(Sha256::digest(
        serde_json::to_vec(value).context("encode offline digest payload")?,
    )))
}

fn normalized_roles(roles: impl IntoIterator<Item = String>) -> Result<Vec<String>> {
    let mut roles = roles
        .into_iter()
        .map(|role| required(&role, "offline role", 64))
        .collect::<Result<BTreeSet<_>>>()?
        .into_iter()
        .collect::<Vec<_>>();
    ensure!(roles.len() <= MAX_OFFLINE_ROLES, "too many offline roles");
    roles.shrink_to_fit();
    Ok(roles)
}

/// Truthful strength of the target-owned proof key.
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "kebab-case")]
pub enum OfflineAssurance {
    Software,
    HardwareBacked,
    Manufacturer,
    Gateway,
}

/// Sign-only boundary used by app-private or hardware-backed storage.
pub trait OfflineSigner: Send + Sync {
    fn verifying_key(&self) -> Result<VerifyingKey>;
    fn sign(&self, message: &[u8]) -> Result<Signature>;
}

/// Software profile for Rust-native devices without a hardware signer.
///
/// The key is intentionally neither serializable nor cloneable. Production
/// hosts should normally implement [`OfflineSigner`] around their private key
/// store instead.
pub struct SoftwareOfflineSigner(SigningKey);

impl SoftwareOfflineSigner {
    pub fn generate() -> Result<Self> {
        let mut seed = [0u8; 32];
        getrandom::getrandom(&mut seed)
            .map_err(|error| anyhow!("generate offline device key: {error}"))?;
        Ok(Self(SigningKey::from_bytes(&seed)))
    }

    #[cfg(test)]
    fn from_seed(seed: [u8; 32]) -> Self {
        Self(SigningKey::from_bytes(&seed))
    }
}

impl OfflineSigner for SoftwareOfflineSigner {
    fn verifying_key(&self) -> Result<VerifyingKey> {
        Ok(self.0.verifying_key())
    }

    fn sign(&self, message: &[u8]) -> Result<Signature> {
        Ok(self.0.sign(message))
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineEnrollmentBody {
    pub protocol: String,
    pub trust_domain: String,
    pub device_id: String,
    pub endpoint_id: String,
    pub proof_public_key: String,
    pub enrollment_nonce: String,
    pub requested_roles: Vec<String>,
    /// Target/host request metadata. Only an issuer-signed credential
    /// certifies assurance.
    pub requested_assurance: OfflineAssurance,
    pub created_at_ms: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineEnrollmentRequest {
    pub body: OfflineEnrollmentBody,
    pub proof_signature: String,
}

impl OfflineEnrollmentRequest {
    #[allow(clippy::too_many_arguments)]
    pub fn create(
        signer: &dyn OfflineSigner,
        trust_domain: &str,
        device_id: &str,
        endpoint_id: &str,
        enrollment_nonce: &str,
        requested_roles: Vec<String>,
        requested_assurance: OfflineAssurance,
        created_at_ms: u64,
    ) -> Result<Self> {
        let proof_key = signer.verifying_key()?;
        let body = OfflineEnrollmentBody {
            protocol: OFFLINE_DEVICE_PROTOCOL.to_string(),
            trust_domain: required(trust_domain, "trust domain", 128)?,
            device_id: required(device_id, "device id", 192)?,
            endpoint_id: required(endpoint_id, "endpoint id", 192)?,
            proof_public_key: URL_SAFE_NO_PAD.encode(proof_key.as_bytes()),
            enrollment_nonce: required(enrollment_nonce, "enrollment nonce", 192)?,
            requested_roles: normalized_roles(requested_roles)?,
            requested_assurance,
            created_at_ms,
        };
        let signed = canonical_bytes("openrtc:offline-enrollment:v1", &body)?;
        Ok(Self {
            body,
            proof_signature: URL_SAFE_NO_PAD.encode(signer.sign(&signed)?.to_bytes()),
        })
    }

    pub fn verify(&self) -> Result<VerifyingKey> {
        ensure!(
            self.body.protocol == OFFLINE_DEVICE_PROTOCOL,
            "unsupported offline enrollment protocol"
        );
        required(&self.body.trust_domain, "trust domain", 128)?;
        required(&self.body.device_id, "device id", 192)?;
        required(&self.body.endpoint_id, "endpoint id", 192)?;
        required(&self.body.enrollment_nonce, "enrollment nonce", 192)?;
        ensure!(
            normalized_roles(self.body.requested_roles.clone())? == self.body.requested_roles,
            "offline enrollment roles are not canonical"
        );
        let key = public_key(&self.body.proof_public_key)?;
        key.verify(
            &canonical_bytes("openrtc:offline-enrollment:v1", &self.body)?,
            &signature(&self.proof_signature)?,
        )
        .context("verify enrollment proof of possession")?;
        Ok(key)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineDeviceCredentialBody {
    pub protocol: String,
    pub trust_domain: String,
    pub serial: String,
    pub issuer_key_id: String,
    pub trust_generation: u64,
    pub device_id: String,
    pub endpoint_id: String,
    pub proof_public_key: String,
    pub roles: Vec<String>,
    pub assurance: OfflineAssurance,
    pub not_before_ms: u64,
    pub expires_at_ms: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineDeviceCredential {
    pub body: OfflineDeviceCredentialBody,
    pub issuer_signature: String,
}

impl OfflineDeviceCredential {
    /// Issue a credential under fleet policy. `assurance` is an explicit
    /// issuer decision and is never copied from the enrollment request.
    #[allow(clippy::too_many_arguments)]
    pub fn issue(
        issuer: &dyn OfflineSigner,
        request: &OfflineEnrollmentRequest,
        serial: &str,
        trust_generation: u64,
        roles: Vec<String>,
        assurance: OfflineAssurance,
        not_before_ms: u64,
        expires_at_ms: u64,
    ) -> Result<Self> {
        request.verify()?;
        ensure!(
            expires_at_ms > not_before_ms,
            "credential expiry is invalid"
        );
        ensure!(
            trust_generation > 0,
            "credential generation must be positive"
        );
        let roles = normalized_roles(roles)?;
        ensure!(
            roles
                .iter()
                .all(|role| request.body.requested_roles.contains(role)),
            "credential grants a role the device did not request"
        );
        let issuer_key = issuer.verifying_key()?;
        let body = OfflineDeviceCredentialBody {
            protocol: OFFLINE_DEVICE_PROTOCOL.to_string(),
            trust_domain: request.body.trust_domain.clone(),
            serial: required(serial, "credential serial", 192)?,
            issuer_key_id: key_id(&issuer_key),
            trust_generation,
            device_id: request.body.device_id.clone(),
            endpoint_id: request.body.endpoint_id.clone(),
            proof_public_key: request.body.proof_public_key.clone(),
            roles,
            assurance,
            not_before_ms,
            expires_at_ms,
        };
        let signed = canonical_bytes("openrtc:offline-credential:v1", &body)?;
        Ok(Self {
            body,
            issuer_signature: URL_SAFE_NO_PAD.encode(issuer.sign(&signed)?.to_bytes()),
        })
    }

    pub fn verify(&self, issuer: &VerifyingKey, at_ms: u64) -> Result<VerifyingKey> {
        ensure!(
            self.body.not_before_ms <= at_ms,
            "credential is not active yet"
        );
        ensure!(at_ms < self.body.expires_at_ms, "credential expired");
        self.verify_signed(issuer)
    }

    fn verify_signed(&self, issuer: &VerifyingKey) -> Result<VerifyingKey> {
        ensure!(
            self.body.protocol == OFFLINE_DEVICE_PROTOCOL,
            "unsupported credential"
        );
        ensure!(
            self.body.issuer_key_id == key_id(issuer),
            "credential issuer mismatch"
        );
        ensure!(
            self.body.expires_at_ms > self.body.not_before_ms,
            "credential expiry is invalid"
        );
        ensure!(
            self.body.trust_generation > 0,
            "credential generation is invalid"
        );
        required(&self.body.trust_domain, "trust domain", 128)?;
        required(&self.body.serial, "credential serial", 192)?;
        required(&self.body.device_id, "device id", 192)?;
        required(&self.body.endpoint_id, "endpoint id", 192)?;
        ensure!(
            normalized_roles(self.body.roles.clone())? == self.body.roles,
            "credential roles are not canonical"
        );
        issuer
            .verify(
                &canonical_bytes("openrtc:offline-credential:v1", &self.body)?,
                &signature(&self.issuer_signature)?,
            )
            .context("verify device credential")?;
        public_key(&self.body.proof_public_key)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineTrustBundleBody {
    pub protocol: String,
    pub trust_domain: String,
    pub issuer_public_key: String,
    pub issuer_key_id: String,
    pub generation: u64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub parent_digest: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub recovery_from_key_id: Option<String>,
    pub credentials: Vec<OfflineDeviceCredential>,
    pub revoked_serials: Vec<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineTrustBundle {
    pub body: OfflineTrustBundleBody,
    pub issuer_signature: String,
}

impl OfflineTrustBundle {
    #[allow(clippy::too_many_arguments)]
    pub fn issue(
        issuer: &dyn OfflineSigner,
        trust_domain: &str,
        generation: u64,
        parent_digest: Option<String>,
        recovery_from_key_id: Option<String>,
        credentials: Vec<OfflineDeviceCredential>,
        revoked_serials: Vec<String>,
    ) -> Result<Self> {
        ensure!(generation > 0, "trust-bundle generation must be positive");
        ensure!(
            credentials.len() <= MAX_OFFLINE_CREDENTIALS,
            "too many credentials"
        );
        ensure!(
            revoked_serials.len() <= MAX_OFFLINE_REVOKED_SERIALS,
            "too many revoked credential serials"
        );
        let issuer_key = issuer.verifying_key()?;
        let revoked_serials = revoked_serials
            .into_iter()
            .map(|serial| required(&serial, "revoked serial", 192))
            .collect::<Result<BTreeSet<_>>>()?
            .into_iter()
            .collect();
        let body = OfflineTrustBundleBody {
            protocol: OFFLINE_TRUST_BUNDLE_PROTOCOL.to_string(),
            trust_domain: required(trust_domain, "trust domain", 128)?,
            issuer_public_key: URL_SAFE_NO_PAD.encode(issuer_key.as_bytes()),
            issuer_key_id: key_id(&issuer_key),
            generation,
            parent_digest,
            recovery_from_key_id,
            credentials,
            revoked_serials,
        };
        let signed = canonical_bytes("openrtc:offline-trust-bundle:v1", &body)?;
        Ok(Self {
            body,
            issuer_signature: URL_SAFE_NO_PAD.encode(issuer.sign(&signed)?.to_bytes()),
        })
    }

    pub fn digest(&self) -> Result<String> {
        digest_json(self)
    }

    pub fn verify(&self, at_ms: u64) -> Result<VerifyingKey> {
        let issuer = self.verify_signed()?;
        for credential in &self.body.credentials {
            credential.verify(&issuer, at_ms)?;
        }
        Ok(issuer)
    }

    fn verify_signed(&self) -> Result<VerifyingKey> {
        ensure!(
            self.body.protocol == OFFLINE_TRUST_BUNDLE_PROTOCOL,
            "unsupported trust-bundle protocol"
        );
        ensure!(
            self.body.generation > 0,
            "trust-bundle generation is invalid"
        );
        ensure!(
            self.body.credentials.len() <= MAX_OFFLINE_CREDENTIALS,
            "too many credentials"
        );
        ensure!(
            self.body.revoked_serials.len() <= MAX_OFFLINE_REVOKED_SERIALS,
            "too many revoked credential serials"
        );
        required(&self.body.trust_domain, "trust domain", 128)?;
        let issuer = public_key(&self.body.issuer_public_key)?;
        ensure!(
            self.body.issuer_key_id == key_id(&issuer),
            "trust-bundle issuer mismatch"
        );
        issuer
            .verify(
                &canonical_bytes("openrtc:offline-trust-bundle:v1", &self.body)?,
                &signature(&self.issuer_signature)?,
            )
            .context("verify trust bundle")?;
        let revoked = self
            .body
            .revoked_serials
            .iter()
            .map(|serial| required(serial, "revoked serial", 192))
            .collect::<Result<BTreeSet<_>>>()?;
        ensure!(
            revoked.len() == self.body.revoked_serials.len(),
            "revoked serials are not canonical"
        );
        let mut devices = BTreeSet::new();
        let mut serials = BTreeSet::new();
        for credential in &self.body.credentials {
            credential.verify_signed(&issuer)?;
            ensure!(
                credential.body.trust_domain == self.body.trust_domain,
                "credential trust domain mismatch"
            );
            ensure!(
                credential.body.trust_generation <= self.body.generation,
                "credential generation is newer than its trust bundle"
            );
            ensure!(
                devices.insert(&credential.body.device_id),
                "duplicate device credential"
            );
            ensure!(
                serials.insert(&credential.body.serial),
                "duplicate credential serial"
            );
            ensure!(
                !revoked.contains(&credential.body.serial),
                "trust bundle includes a revoked credential"
            );
        }
        Ok(issuer)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineTrustHighWater {
    pub trust_domain: String,
    pub issuer_key_id: String,
    pub generation: u64,
    pub digest: String,
}

/// Trust-validated local reachability input. It is not a dial command and it
/// is not an admission verdict. Only the existing Rust peer actor may turn it
/// into a transport attempt.
#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone)]
pub struct OfflineCandidateHandoff {
    trust_domain: String,
    trust_generation: u64,
    credential_serial: String,
    device_id: String,
    endpoint_addr: iroh::EndpointAddr,
    roles: Vec<String>,
    assurance: OfflineAssurance,
}

#[cfg(not(target_arch = "wasm32"))]
impl OfflineCandidateHandoff {
    pub fn device_id(&self) -> &str {
        &self.device_id
    }

    pub fn endpoint_addr(&self) -> &iroh::EndpointAddr {
        &self.endpoint_addr
    }

    pub fn trust_generation(&self) -> u64 {
        self.trust_generation
    }

    pub(crate) fn same_authority(&self, other: &Self) -> bool {
        self.trust_domain == other.trust_domain
            && self.trust_generation == other.trust_generation
            && self.credential_serial == other.credential_serial
            && self.device_id == other.device_id
            && self.endpoint_addr.id == other.endpoint_addr.id
    }
}

/// Exact local physical generation to which a fresh offline proof is bound.
#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct OfflineTransportBinding {
    pub local_endpoint_id: String,
    pub remote_endpoint_id: String,
    pub transport_stable_id: u64,
}

/// Opaque proof verdict consumed by the existing Rust admission owner.
#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone)]
pub struct OfflineAdmissionHandoff {
    candidate: OfflineCandidateHandoff,
    binding: OfflineTransportBinding,
    replay_id: String,
}

#[cfg(not(target_arch = "wasm32"))]
impl OfflineAdmissionHandoff {
    pub fn device_id(&self) -> &str {
        self.candidate.device_id()
    }

    pub fn remote_endpoint_id(&self) -> &str {
        &self.binding.remote_endpoint_id
    }

    pub fn transport_stable_id(&self) -> u64 {
        self.binding.transport_stable_id
    }

    pub fn roles(&self) -> &[String] {
        &self.candidate.roles
    }

    pub fn assurance(&self) -> OfflineAssurance {
        self.candidate.assurance
    }

    pub fn replay_id(&self) -> &str {
        &self.replay_id
    }

    pub(crate) fn candidate(&self) -> &OfflineCandidateHandoff {
        &self.candidate
    }

    pub(crate) fn binding(&self) -> &OfflineTransportBinding {
        &self.binding
    }
}

/// Persist this value atomically after [`OfflineTrustState::apply`] succeeds.
#[derive(Debug, Clone)]
pub struct OfflineTrustState {
    pinned_trust_domain: String,
    pinned_issuer: VerifyingKey,
    recovery_issuers: BTreeMap<String, VerifyingKey>,
    current: Option<OfflineTrustBundle>,
}

impl OfflineTrustState {
    pub fn new(trust_domain: &str, issuer: VerifyingKey) -> Result<Self> {
        Ok(Self {
            pinned_trust_domain: required(trust_domain, "trust domain", 128)?,
            pinned_issuer: issuer,
            recovery_issuers: BTreeMap::new(),
            current: None,
        })
    }

    pub fn allow_recovery_issuer(&mut self, issuer: VerifyingKey) {
        self.recovery_issuers.insert(key_id(&issuer), issuer);
    }

    pub fn high_water(&self) -> Result<Option<OfflineTrustHighWater>> {
        self.current
            .as_ref()
            .map(|bundle| {
                Ok(OfflineTrustHighWater {
                    trust_domain: bundle.body.trust_domain.clone(),
                    issuer_key_id: bundle.body.issuer_key_id.clone(),
                    generation: bundle.body.generation,
                    digest: bundle.digest()?,
                })
            })
            .transpose()
    }

    pub fn apply(&mut self, next: OfflineTrustBundle, at_ms: u64) -> Result<OfflineTrustHighWater> {
        let next_issuer = next.verify(at_ms)?;
        self.apply_verified(next, next_issuer)
    }

    /// Replay persisted lineage without requiring credentials in historical
    /// generations to still be active today. Signatures, canonical structure,
    /// issuer recovery, and every parent digest remain fully verified.
    #[cfg(not(target_arch = "wasm32"))]
    fn apply_historical(&mut self, next: OfflineTrustBundle) -> Result<OfflineTrustHighWater> {
        let next_issuer = next.verify_signed()?;
        self.apply_verified(next, next_issuer)
    }

    fn apply_verified(
        &mut self,
        next: OfflineTrustBundle,
        next_issuer: VerifyingKey,
    ) -> Result<OfflineTrustHighWater> {
        ensure!(
            next.body.trust_domain == self.pinned_trust_domain,
            "trust-domain substitution rejected"
        );
        let next_digest = next.digest()?;
        match &self.current {
            None => {
                ensure!(
                    next_issuer == self.pinned_issuer && next.body.recovery_from_key_id.is_none(),
                    "initial trust bundle must use the pinned issuer"
                );
                ensure!(
                    next.body.parent_digest.is_none(),
                    "initial bundle has a parent"
                );
            }
            Some(current) => {
                let current_digest = current.digest()?;
                ensure!(
                    next.body.generation > current.body.generation,
                    if next.body.generation == current.body.generation
                        && next_digest != current_digest
                    {
                        "equal-generation trust-bundle fork rejected"
                    } else {
                        "trust-bundle rollback rejected"
                    }
                );
                ensure!(
                    next.body.parent_digest.as_deref() == Some(current_digest.as_str()),
                    "broken trust-bundle lineage rejected"
                );
                if next.body.issuer_key_id != current.body.issuer_key_id {
                    ensure!(
                        next.body.recovery_from_key_id.as_deref()
                            == Some(current.body.issuer_key_id.as_str()),
                        "issuer substitution rejected"
                    );
                    ensure!(
                        self.recovery_issuers.get(&next.body.issuer_key_id) == Some(&next_issuer),
                        "unauthorized recovery issuer rejected"
                    );
                } else {
                    ensure!(
                        next.body.recovery_from_key_id.is_none(),
                        "ordinary trust update cannot claim recovery"
                    );
                }
            }
        }
        let high_water = OfflineTrustHighWater {
            trust_domain: next.body.trust_domain.clone(),
            issuer_key_id: next.body.issuer_key_id.clone(),
            generation: next.body.generation,
            digest: next_digest,
        };
        self.current = Some(next);
        Ok(high_water)
    }

    pub fn credential(&self, device_id: &str, at_ms: u64) -> Result<&OfflineDeviceCredential> {
        let bundle = self
            .current
            .as_ref()
            .ok_or_else(|| anyhow!("no trust bundle installed"))?;
        let issuer = bundle.verify(at_ms)?;
        let credential = bundle
            .body
            .credentials
            .iter()
            .find(|credential| credential.body.device_id == device_id)
            .ok_or_else(|| anyhow!("device is not in the current trust bundle"))?;
        ensure!(
            !bundle
                .body
                .revoked_serials
                .contains(&credential.body.serial),
            "device credential is revoked"
        );
        credential.verify(&issuer, at_ms)?;
        Ok(credential)
    }

    #[cfg(all(not(target_arch = "wasm32"), feature = "transport-lan"))]
    pub(crate) fn device_id_for_endpoint(&self, endpoint_id: &str, at_ms: u64) -> Result<String> {
        let bundle = self
            .current
            .as_ref()
            .ok_or_else(|| anyhow!("no trust bundle installed"))?;
        let credential = bundle
            .body
            .credentials
            .iter()
            .find(|credential| credential.body.endpoint_id == endpoint_id)
            .ok_or_else(|| anyhow!("local observation is not in the current trust bundle"))?;
        self.credential(&credential.body.device_id, at_ms)?;
        Ok(credential.body.device_id.clone())
    }

    /// Verify one fresh proof against the currently accepted bundle. This is
    /// the safe public entrypoint: callers cannot skip expiry, revocation,
    /// issuer, domain, or bundle-generation validation.
    pub fn verify_connection_proof(
        &self,
        proof: &OfflineConnectionProof,
        expected: &OfflineProofTranscript,
        replay_cache: &mut OfflineReplayCache,
        at_ms: u64,
    ) -> Result<OfflineAdmission> {
        let credential = self.credential(&expected.presenter_device_id, at_ms)?;
        verify_connection_proof(proof, credential, expected, replay_cache)
    }

    /// Convert one local observation into typed admission intent. The result
    /// still cannot dial or route traffic.
    #[cfg(all(not(target_arch = "wasm32"), feature = "transport-lan"))]
    pub fn authorize_local_candidate(
        &self,
        device_id: &str,
        endpoint_addr: iroh::EndpointAddr,
        at_ms: u64,
    ) -> Result<OfflineCandidateHandoff> {
        ensure!(
            crate::local_discovery::endpoint_addr_is_local_only(&endpoint_addr, &[]),
            "offline candidate contains a non-local address"
        );
        let credential = self.credential(device_id, at_ms)?;
        ensure!(
            credential.body.endpoint_id == endpoint_addr.id.to_string(),
            "offline candidate endpoint does not match its credential"
        );
        let generation = self
            .current
            .as_ref()
            .map(|bundle| bundle.body.generation)
            .ok_or_else(|| anyhow!("no trust bundle installed"))?;
        Ok(OfflineCandidateHandoff {
            trust_domain: credential.body.trust_domain.clone(),
            trust_generation: generation,
            credential_serial: credential.body.serial.clone(),
            device_id: credential.body.device_id.clone(),
            endpoint_addr,
            roles: credential.body.roles.clone(),
            assurance: credential.body.assurance,
        })
    }

    /// Verify a fresh connection proof and bind its verdict to one exact
    /// physical generation. The returned handoff is opaque to adapters and is
    /// committed only by the existing Rust admission owner.
    #[cfg(not(target_arch = "wasm32"))]
    pub fn verify_transport_proof(
        &self,
        candidate: &OfflineCandidateHandoff,
        proof: &OfflineConnectionProof,
        expected: &OfflineProofTranscript,
        binding: OfflineTransportBinding,
        replay_cache: &mut OfflineReplayCache,
        at_ms: u64,
    ) -> Result<OfflineAdmissionHandoff> {
        ensure!(
            binding.transport_stable_id > 0,
            "invalid transport generation"
        );
        ensure!(
            expected.presenter_endpoint_id == binding.remote_endpoint_id
                && expected.verifier_endpoint_id == binding.local_endpoint_id,
            "offline proof is not bound to the supplied transport endpoints"
        );
        ensure!(
            expected.transport_stable_id == binding.transport_stable_id,
            "offline proof is not bound to the supplied transport generation"
        );
        ensure!(
            candidate.endpoint_addr.id.to_string() == binding.remote_endpoint_id,
            "offline candidate changed endpoints"
        );
        let current = self
            .credential(candidate.device_id(), at_ms)
            .context("offline candidate credential is no longer current")?;
        ensure!(
            current.body.serial == candidate.credential_serial
                && current.body.trust_domain == candidate.trust_domain,
            "offline candidate trust facts changed"
        );
        let current_generation = self
            .current
            .as_ref()
            .map(|bundle| bundle.body.generation)
            .ok_or_else(|| anyhow!("no trust bundle installed"))?;
        ensure!(
            current_generation == candidate.trust_generation,
            "offline candidate trust generation is stale"
        );
        let admission = verify_connection_proof(proof, current, expected, replay_cache)?;
        ensure!(
            admission.authoritative_device_id == candidate.device_id,
            "offline admission device mismatch"
        );
        Ok(OfflineAdmissionHandoff {
            candidate: candidate.clone(),
            binding,
            replay_id: proof.replay_id()?,
        })
    }
}

#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
struct OfflineTrustJournal {
    protocol: String,
    history: Vec<OfflineTrustBundle>,
    high_water: OfflineTrustHighWater,
    #[serde(default)]
    replay_ids: Vec<String>,
}

#[cfg(not(target_arch = "wasm32"))]
fn read_bounded_json<T: serde::de::DeserializeOwned>(path: &Path) -> Result<Option<T>> {
    let metadata = match std::fs::symlink_metadata(path) {
        Ok(metadata) => metadata,
        Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Ok(None),
        Err(error) => return Err(error).with_context(|| format!("inspect {}", path.display())),
    };
    ensure!(
        !metadata.file_type().is_symlink(),
        "offline trust path is a symlink"
    );
    ensure!(
        metadata.len() <= MAX_OFFLINE_TRUST_JOURNAL_BYTES,
        "offline trust record exceeds the size bound"
    );
    serde_json::from_slice(
        &std::fs::read(path).with_context(|| format!("read {}", path.display()))?,
    )
    .with_context(|| format!("decode {}", path.display()))
    .map(Some)
}

#[cfg(not(target_arch = "wasm32"))]
fn write_private_json(path: &Path, value: &impl Serialize) -> Result<()> {
    use std::io::Write as _;

    let payload = serde_json::to_vec(value).context("encode offline trust record")?;
    ensure!(
        payload.len() as u64 <= MAX_OFFLINE_TRUST_JOURNAL_BYTES,
        "offline trust record exceeds the size bound"
    );
    let parent = path
        .parent()
        .filter(|parent| !parent.as_os_str().is_empty())
        .unwrap_or_else(|| Path::new("."));
    std::fs::create_dir_all(parent)
        .with_context(|| format!("create offline trust directory {}", parent.display()))?;
    let file_name = path
        .file_name()
        .and_then(|name| name.to_str())
        .ok_or_else(|| anyhow!("offline trust path requires a file name"))?;
    let temp = parent.join(format!(
        ".{file_name}.tmp-{}-{}",
        std::process::id(),
        crate::session_token::generate_nonce()
    ));
    let mut options = std::fs::OpenOptions::new();
    options.write(true).create_new(true);
    #[cfg(unix)]
    {
        use std::os::unix::fs::OpenOptionsExt;
        options.mode(0o600);
    }
    let result = (|| {
        let mut file = options
            .open(&temp)
            .with_context(|| format!("create {}", temp.display()))?;
        file.write_all(&payload)
            .with_context(|| format!("write {}", temp.display()))?;
        file.sync_all()
            .with_context(|| format!("sync {}", temp.display()))?;
        drop(file);
        #[cfg(windows)]
        if path.exists() {
            std::fs::remove_file(path).with_context(|| format!("replace {}", path.display()))?;
        }
        std::fs::rename(&temp, path).with_context(|| format!("install {}", path.display()))?;
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            std::fs::set_permissions(path, std::fs::Permissions::from_mode(0o600))
                .with_context(|| format!("secure {}", path.display()))?;
            std::fs::File::open(parent)
                .and_then(|directory| directory.sync_all())
                .with_context(|| format!("sync directory {}", parent.display()))?;
        }
        Ok::<(), anyhow::Error>(())
    })();
    if result.is_err() {
        let _ = std::fs::remove_file(&temp);
    }
    result
}

/// Native, restart-safe trust journal. The bundle journal is written before a
/// separate high-water anchor so a crash can advance but never silently roll
/// back accepted trust. Hosts facing malicious whole-disk rollback should put
/// the anchor path on platform anti-rollback storage.
#[cfg(not(target_arch = "wasm32"))]
pub struct DurableOfflineTrustState {
    state_path: PathBuf,
    high_water_path: PathBuf,
    state: OfflineTrustState,
    history: Vec<OfflineTrustBundle>,
    replay_cache: OfflineReplayCache,
}

#[cfg(not(target_arch = "wasm32"))]
impl DurableOfflineTrustState {
    pub fn open(
        state_path: impl Into<PathBuf>,
        trust_domain: &str,
        pinned_issuer: VerifyingKey,
        recovery_issuers: impl IntoIterator<Item = VerifyingKey>,
        at_ms: u64,
    ) -> Result<Self> {
        let state_path = state_path.into();
        let high_water_path = state_path.with_extension("high-water.json");
        let persisted_anchor = read_bounded_json::<OfflineTrustHighWater>(&high_water_path)?;
        let journal = read_bounded_json::<OfflineTrustJournal>(&state_path)?;
        ensure!(
            journal.is_some() || persisted_anchor.is_none(),
            "offline trust journal is missing behind its high-water anchor"
        );

        let recovery_issuers = recovery_issuers.into_iter().collect::<Vec<_>>();
        let mut state = OfflineTrustState::new(trust_domain, pinned_issuer)?;
        for issuer in recovery_issuers {
            state.allow_recovery_issuer(issuer);
        }
        let mut history = Vec::new();
        let mut replay_cache = OfflineReplayCache::default();
        let mut accepted = Vec::new();
        if let Some(journal) = journal {
            ensure!(
                journal.protocol == OFFLINE_TRUST_JOURNAL_PROTOCOL,
                "unsupported offline trust journal"
            );
            ensure!(
                !journal.history.is_empty(),
                "offline trust journal is empty"
            );
            ensure!(
                journal.history.len() <= MAX_OFFLINE_TRUST_HISTORY,
                "offline trust journal exceeds the history bound"
            );
            for bundle in journal.history.iter().cloned() {
                accepted.push(state.apply_historical(bundle)?);
            }
            ensure!(
                accepted.last() == Some(&journal.high_water),
                "offline trust journal high-water mismatch"
            );
            replay_cache =
                OfflineReplayCache::from_entries(MAX_OFFLINE_REPLAY_ENTRIES, journal.replay_ids)?;
            history = journal.history;

            if let Some(anchor) = persisted_anchor.as_ref() {
                ensure!(
                    accepted.iter().any(|water| water == anchor),
                    "offline trust rollback or fork rejected by high-water anchor"
                );
            }
            // The journal can outlive earlier credentials, but the current
            // generation must still satisfy time validity before startup can
            // expose it as usable trust or repair the anchor.
            state
                .current
                .as_ref()
                .expect("non-empty accepted trust history")
                .verify(at_ms)?;
            if persisted_anchor.as_ref() != accepted.last() {
                write_private_json(
                    &high_water_path,
                    accepted.last().expect("non-empty accepted trust history"),
                )?;
            }
        }

        Ok(Self {
            state_path,
            high_water_path,
            state,
            history,
            replay_cache,
        })
    }

    pub fn trust(&self) -> &OfflineTrustState {
        &self.state
    }

    pub fn apply(&mut self, next: OfflineTrustBundle, at_ms: u64) -> Result<OfflineTrustHighWater> {
        ensure!(
            self.history.len() < MAX_OFFLINE_TRUST_HISTORY,
            "offline trust journal history is full"
        );
        let mut state = self.state.clone();
        let high_water = state.apply(next.clone(), at_ms)?;
        let mut history = self.history.clone();
        history.push(next);
        let journal = OfflineTrustJournal {
            protocol: OFFLINE_TRUST_JOURNAL_PROTOCOL.to_string(),
            history: history.clone(),
            high_water: high_water.clone(),
            replay_ids: self.replay_cache.entries(),
        };
        write_private_json(&self.state_path, &journal)?;
        let anchor_result = write_private_json(&self.high_water_path, &high_water);
        // The journal is authoritative after its atomic install even if the
        // secondary anchor sync fails. A restart repairs an older anchor from
        // the validated journal; keeping old memory here would enable rollback.
        self.state = state;
        self.history = history;
        anchor_result?;
        Ok(high_water)
    }

    /// Verify and persist one accepted proof replay id before exposing its
    /// admission handoff. A crash can therefore lose an uncommitted admission,
    /// but cannot make an already-returned proof reusable after restart.
    #[cfg(not(target_arch = "wasm32"))]
    pub fn verify_transport_proof(
        &mut self,
        candidate: &OfflineCandidateHandoff,
        proof: &OfflineConnectionProof,
        expected: &OfflineProofTranscript,
        binding: OfflineTransportBinding,
        at_ms: u64,
    ) -> Result<OfflineAdmissionHandoff> {
        let mut replay_cache = self.replay_cache.clone();
        let handoff = self.state.verify_transport_proof(
            candidate,
            proof,
            expected,
            binding,
            &mut replay_cache,
            at_ms,
        )?;
        let high_water = self
            .state
            .high_water()?
            .ok_or_else(|| anyhow!("no trust bundle installed"))?;
        let journal = OfflineTrustJournal {
            protocol: OFFLINE_TRUST_JOURNAL_PROTOCOL.to_string(),
            history: self.history.clone(),
            high_water,
            replay_ids: replay_cache.entries(),
        };
        write_private_json(&self.state_path, &journal)?;
        self.replay_cache = replay_cache;
        Ok(handoff)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineProofTranscript {
    pub protocol: String,
    pub trust_domain: String,
    pub credential_serial: String,
    pub presenter_device_id: String,
    pub presenter_endpoint_id: String,
    pub verifier_device_id: String,
    pub verifier_endpoint_id: String,
    pub presenter_nonce: String,
    pub verifier_nonce: String,
    /// Exact Rust-owned physical generation covered by this proof.
    pub transport_stable_id: u64,
    pub channel_binding: String,
}

/// One verifier-owned challenge carried on the existing native-main admission
/// classifier. The responder signs a transcript containing these exact facts.
#[cfg(not(target_arch = "wasm32"))]
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub(crate) struct OfflineProofChallenge {
    pub(crate) protocol: String,
    pub(crate) request_id: String,
    pub(crate) verifier_device_id: String,
    pub(crate) verifier_endpoint_id: String,
    pub(crate) verifier_nonce: String,
    pub(crate) transport_stable_id: u64,
    pub(crate) channel_binding: String,
}

#[cfg(not(target_arch = "wasm32"))]
impl OfflineProofChallenge {
    pub(crate) fn validate(&self) -> Result<()> {
        ensure!(
            self.protocol == OFFLINE_PROOF_PROTOCOL,
            "unsupported offline proof challenge"
        );
        required(&self.request_id, "offline proof request id", 192)?;
        required(&self.verifier_device_id, "verifier device id", 192)?;
        required(&self.verifier_endpoint_id, "verifier endpoint id", 192)?;
        required(&self.verifier_nonce, "verifier nonce", 192)?;
        ensure!(
            self.transport_stable_id > 0,
            "offline proof challenge generation is invalid"
        );
        required(&self.channel_binding, "channel binding", 512)?;
        Ok(())
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
pub struct OfflineConnectionProof {
    pub transcript: OfflineProofTranscript,
    pub signature: String,
}

impl OfflineConnectionProof {
    pub fn create(signer: &dyn OfflineSigner, transcript: OfflineProofTranscript) -> Result<Self> {
        validate_transcript(&transcript)?;
        Ok(Self {
            signature: URL_SAFE_NO_PAD.encode(
                signer
                    .sign(&canonical_bytes("openrtc:offline-proof:v1", &transcript)?)?
                    .to_bytes(),
            ),
            transcript,
        })
    }

    pub fn replay_id(&self) -> Result<String> {
        digest_json(self)
    }
}

fn validate_transcript(transcript: &OfflineProofTranscript) -> Result<()> {
    ensure!(
        transcript.protocol == OFFLINE_PROOF_PROTOCOL,
        "unsupported offline proof"
    );
    required(&transcript.trust_domain, "trust domain", 128)?;
    required(&transcript.credential_serial, "credential serial", 192)?;
    required(&transcript.presenter_device_id, "presenter device id", 192)?;
    required(
        &transcript.presenter_endpoint_id,
        "presenter endpoint id",
        192,
    )?;
    required(&transcript.verifier_device_id, "verifier device id", 192)?;
    required(
        &transcript.verifier_endpoint_id,
        "verifier endpoint id",
        192,
    )?;
    required(&transcript.presenter_nonce, "presenter nonce", 192)?;
    required(&transcript.verifier_nonce, "verifier nonce", 192)?;
    ensure!(
        transcript.transport_stable_id > 0,
        "offline proof transport generation is invalid"
    );
    required(&transcript.channel_binding, "channel binding", 512)?;
    ensure!(
        transcript.presenter_device_id != transcript.verifier_device_id,
        "offline proof cannot target the same device"
    );
    Ok(())
}

/// Bounded replay owner. One instance belongs to the Rust admission owner.
#[derive(Debug, Clone)]
pub struct OfflineReplayCache {
    capacity: usize,
    order: VecDeque<String>,
    entries: BTreeSet<String>,
}

impl Default for OfflineReplayCache {
    fn default() -> Self {
        Self::new(MAX_OFFLINE_REPLAY_ENTRIES)
    }
}

impl OfflineReplayCache {
    pub fn new(capacity: usize) -> Self {
        Self {
            capacity: capacity.clamp(1, MAX_OFFLINE_REPLAY_ENTRIES),
            order: VecDeque::new(),
            entries: BTreeSet::new(),
        }
    }

    pub fn accept(&mut self, replay_id: String) -> Result<()> {
        ensure!(
            !self.entries.contains(&replay_id),
            "offline proof replay rejected"
        );
        while self.order.len() >= self.capacity {
            if let Some(oldest) = self.order.pop_front() {
                self.entries.remove(&oldest);
            }
        }
        self.entries.insert(replay_id.clone());
        self.order.push_back(replay_id);
        Ok(())
    }

    fn from_entries(capacity: usize, entries: impl IntoIterator<Item = String>) -> Result<Self> {
        let mut cache = Self::new(capacity);
        for entry in entries {
            required(&entry, "offline replay id", 192)?;
            cache.accept(entry)?;
        }
        Ok(cache)
    }

    fn entries(&self) -> Vec<String> {
        self.order.iter().cloned().collect()
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct OfflineAdmission {
    pub authoritative_device_id: String,
    pub credential_serial: String,
    pub roles: Vec<String>,
    pub assurance: OfflineAssurance,
}

/// Verify a remote proof against the exact current transport facts.
///
/// `expected` must be constructed by the connection owner after it has read
/// both nonces and the current protected-channel binding. A later local
/// generation check remains mandatory before this verdict is committed.
fn verify_connection_proof(
    proof: &OfflineConnectionProof,
    credential: &OfflineDeviceCredential,
    expected: &OfflineProofTranscript,
    replay_cache: &mut OfflineReplayCache,
) -> Result<OfflineAdmission> {
    validate_transcript(expected)?;
    ensure!(
        &proof.transcript == expected,
        "offline proof transcript mismatch"
    );
    ensure!(
        proof.transcript.trust_domain == credential.body.trust_domain,
        "offline proof trust-domain mismatch"
    );
    ensure!(
        proof.transcript.credential_serial == credential.body.serial,
        "offline proof credential mismatch"
    );
    ensure!(
        proof.transcript.presenter_device_id == credential.body.device_id
            && proof.transcript.presenter_endpoint_id == credential.body.endpoint_id,
        "offline proof identity mismatch"
    );
    public_key(&credential.body.proof_public_key)?
        .verify(
            &canonical_bytes("openrtc:offline-proof:v1", &proof.transcript)?,
            &signature(&proof.signature)?,
        )
        .context("verify offline connection proof")?;
    replay_cache.accept(proof.replay_id()?)?;
    Ok(OfflineAdmission {
        authoritative_device_id: credential.body.device_id.clone(),
        credential_serial: credential.body.serial.clone(),
        roles: credential.body.roles.clone(),
        assurance: credential.body.assurance,
    })
}

/// Deterministic bounded-neighbor intent for a signed offline member set.
///
/// The result is only desired-peer input. The existing Rust actor still owns
/// every dial, retry, admission, generation replacement, and withdrawal.
pub fn bounded_swarm_neighbors(
    local_device_id: &str,
    member_device_ids: impl IntoIterator<Item = String>,
    requested_degree: usize,
) -> Result<Vec<String>> {
    let local = required(local_device_id, "local device id", 192)?;
    let members = member_device_ids
        .into_iter()
        .map(|member| required(&member, "swarm device id", 192))
        .collect::<Result<BTreeSet<_>>>()?;
    ensure!(
        members.len() <= MAX_OFFLINE_SWARM_MEMBERS,
        "offline swarm is too large"
    );
    ensure!(
        members.contains(&local),
        "local device is not in the offline swarm"
    );
    if members.len() <= 1 {
        return Ok(Vec::new());
    }
    let members = members.into_iter().collect::<Vec<_>>();
    let index = members.iter().position(|member| member == &local).unwrap();
    let degree = requested_degree
        .clamp(1, MAX_OFFLINE_SWARM_DEGREE)
        .min(members.len() - 1);
    let mut neighbors = BTreeSet::new();
    for distance in 1..members.len() {
        neighbors.insert(members[(index + distance) % members.len()].clone());
        if neighbors.len() == degree {
            break;
        }
        neighbors.insert(members[(index + members.len() - distance) % members.len()].clone());
        if neighbors.len() == degree {
            break;
        }
    }
    Ok(neighbors.into_iter().collect())
}

#[cfg(test)]
mod tests {
    use super::*;

    fn fixture() -> (
        SoftwareOfflineSigner,
        SoftwareOfflineSigner,
        OfflineEnrollmentRequest,
        OfflineDeviceCredential,
    ) {
        let issuer = SoftwareOfflineSigner::from_seed([1; 32]);
        let device = SoftwareOfflineSigner::from_seed([2; 32]);
        let request = OfflineEnrollmentRequest::create(
            &device,
            "field-a",
            "device-a",
            "endpoint-a",
            "enroll-a",
            vec!["sensor".into()],
            OfflineAssurance::HardwareBacked,
            1_000,
        )
        .unwrap();
        let credential = OfflineDeviceCredential::issue(
            &issuer,
            &request,
            "serial-a",
            1,
            vec!["sensor".into()],
            OfflineAssurance::Software,
            1_000,
            10_000,
        )
        .unwrap();
        (issuer, device, request, credential)
    }

    #[test]
    fn enrollment_and_credential_require_both_target_and_issuer_signatures() {
        let (issuer, _, mut request, credential) = fixture();
        request.body.device_id = "attacker".into();
        assert!(request.verify().is_err());
        credential
            .verify(&issuer.verifying_key().unwrap(), 2_000)
            .unwrap();
        let wrong = SoftwareOfflineSigner::from_seed([9; 32]);
        assert!(credential
            .verify(&wrong.verifying_key().unwrap(), 2_000)
            .is_err());
    }

    #[test]
    fn request_cannot_self_certify_hardware_assurance() {
        let (_, _, request, credential) = fixture();
        assert_eq!(
            request.body.requested_assurance,
            OfflineAssurance::HardwareBacked
        );
        assert_eq!(
            credential.body.assurance,
            OfflineAssurance::Software,
            "the issuer, not the request, certifies credential assurance"
        );
    }

    #[test]
    fn trust_bundle_rejects_rollback_fork_and_unapproved_issuer_recovery() {
        let (issuer, _, _, credential) = fixture();
        let first = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            1,
            None,
            None,
            vec![credential.clone()],
            vec![],
        )
        .unwrap();
        let mut state = OfflineTrustState::new("field-a", issuer.verifying_key().unwrap()).unwrap();
        let first_water = state.apply(first, 2_000).unwrap();

        let fork = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            1,
            None,
            None,
            vec![credential.clone()],
            vec![],
        )
        .unwrap();
        assert!(state.apply(fork, 2_000).is_err());
        assert_eq!(state.high_water().unwrap(), Some(first_water.clone()));

        let attacker = SoftwareOfflineSigner::from_seed([7; 32]);
        let recovery = OfflineTrustBundle::issue(
            &attacker,
            "field-a",
            2,
            Some(first_water.digest.clone()),
            Some(first_water.issuer_key_id.clone()),
            vec![],
            vec![credential.body.serial],
        )
        .unwrap();
        assert!(state.apply(recovery, 2_000).is_err());
        assert_eq!(state.high_water().unwrap(), Some(first_water));
    }

    #[test]
    fn proof_binds_both_peers_nonces_channel_and_rejects_replay() {
        let (_, device, _, credential) = fixture();
        let transcript = OfflineProofTranscript {
            protocol: OFFLINE_PROOF_PROTOCOL.into(),
            trust_domain: "field-a".into(),
            credential_serial: "serial-a".into(),
            presenter_device_id: "device-a".into(),
            presenter_endpoint_id: "endpoint-a".into(),
            verifier_device_id: "device-b".into(),
            verifier_endpoint_id: "endpoint-b".into(),
            presenter_nonce: "presenter-nonce".into(),
            verifier_nonce: "verifier-nonce".into(),
            transport_stable_id: 7,
            channel_binding: "quic-exporter-current-generation".into(),
        };
        let proof = OfflineConnectionProof::create(&device, transcript.clone()).unwrap();
        let mut replay = OfflineReplayCache::new(8);
        let (issuer, _, _, _) = fixture();
        let bundle =
            OfflineTrustBundle::issue(&issuer, "field-a", 1, None, None, vec![credential], vec![])
                .unwrap();
        let mut state = OfflineTrustState::new("field-a", issuer.verifying_key().unwrap()).unwrap();
        state.apply(bundle, 2_000).unwrap();
        state
            .verify_connection_proof(&proof, &transcript, &mut replay, 2_000)
            .unwrap();
        assert!(state
            .verify_connection_proof(&proof, &transcript, &mut replay, 2_000)
            .is_err());

        let mut wrong_generation = transcript;
        wrong_generation.transport_stable_id = 8;
        wrong_generation.channel_binding = "retired-generation".into();
        assert!(state
            .verify_connection_proof(
                &proof,
                &wrong_generation,
                &mut OfflineReplayCache::new(8),
                2_000,
            )
            .is_err());
    }

    #[cfg(not(target_arch = "wasm32"))]
    #[test]
    fn durable_trust_restart_rejects_rollback_fork_and_preserves_revocation() {
        let (issuer, _, _, credential) = fixture();
        let state_dir = std::env::temp_dir().join(format!(
            "openrtc-offline-trust-{}",
            crate::session_token::generate_nonce()
        ));
        std::fs::create_dir_all(&state_dir).unwrap();
        let state_path = state_dir.join("trust.json");
        let first = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            1,
            None,
            None,
            vec![credential.clone()],
            vec![],
        )
        .unwrap();
        let mut durable = DurableOfflineTrustState::open(
            &state_path,
            "field-a",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .unwrap();
        let first_water = durable.apply(first.clone(), 2_000).unwrap();
        let first_journal = std::fs::read(&state_path).unwrap();
        let second = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            2,
            Some(first_water.digest.clone()),
            None,
            vec![],
            vec![credential.body.serial.clone()],
        )
        .unwrap();
        let second_water = durable.apply(second.clone(), 2_000).unwrap();
        let second_journal = std::fs::read(&state_path).unwrap();
        let invalid_fork = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            2,
            Some(first_water.digest.clone()),
            None,
            vec![],
            vec![],
        )
        .unwrap();
        assert!(durable.apply(invalid_fork, 2_000).is_err());
        assert_eq!(
            durable.trust().high_water().unwrap(),
            Some(second_water.clone())
        );
        assert_eq!(std::fs::read(&state_path).unwrap(), second_journal);
        drop(durable);

        let restarted = DurableOfflineTrustState::open(
            &state_path,
            "field-a",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .unwrap();
        assert_eq!(
            restarted.trust().high_water().unwrap(),
            Some(second_water.clone())
        );
        assert!(restarted.trust().credential("device-a", 2_000).is_err());
        drop(restarted);

        std::fs::write(&state_path, &first_journal).unwrap();
        let rollback_error = DurableOfflineTrustState::open(
            &state_path,
            "field-a",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .err()
        .expect("rollback must be rejected")
        .to_string();
        assert!(rollback_error.contains("rollback or fork"));

        let fork = OfflineTrustBundle::issue(
            &issuer,
            "field-a",
            2,
            Some(first_water.digest),
            None,
            vec![credential],
            vec![],
        )
        .unwrap();
        let mut fork_state =
            OfflineTrustState::new("field-a", issuer.verifying_key().unwrap()).unwrap();
        fork_state.apply(first.clone(), 2_000).unwrap();
        let fork_water = fork_state.apply(fork.clone(), 2_000).unwrap();
        write_private_json(
            &state_path,
            &OfflineTrustJournal {
                protocol: OFFLINE_TRUST_JOURNAL_PROTOCOL.to_string(),
                history: vec![first, fork],
                high_water: fork_water,
                replay_ids: Vec::new(),
            },
        )
        .unwrap();
        let fork_error = DurableOfflineTrustState::open(
            &state_path,
            "field-a",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .err()
        .expect("fork must be rejected")
        .to_string();
        assert!(fork_error.contains("rollback or fork"));

        std::fs::write(&state_path, second_journal).unwrap();
        let restored = DurableOfflineTrustState::open(
            &state_path,
            "field-a",
            issuer.verifying_key().unwrap(),
            [],
            20_000,
        )
        .unwrap();
        assert_eq!(restored.trust().high_water().unwrap(), Some(second_water));
        assert!(restored.trust().credential("device-a", 20_000).is_err());
        std::fs::remove_dir_all(&state_dir).unwrap();
    }

    #[cfg(all(not(target_arch = "wasm32"), feature = "transport-lan"))]
    #[test]
    fn durable_trust_restart_rejects_an_already_accepted_proof() {
        let issuer = SoftwareOfflineSigner::from_seed([11; 32]);
        let device = SoftwareOfflineSigner::from_seed([12; 32]);
        let local_endpoint = iroh::SecretKey::generate().public();
        let remote_endpoint = iroh::SecretKey::generate().public();
        let request = OfflineEnrollmentRequest::create(
            &device,
            "field-replay",
            "device-a",
            &remote_endpoint.to_string(),
            "enroll-replay",
            vec!["sensor".into()],
            OfflineAssurance::Software,
            1_000,
        )
        .unwrap();
        let credential = OfflineDeviceCredential::issue(
            &issuer,
            &request,
            "serial-replay",
            1,
            vec!["sensor".into()],
            OfflineAssurance::Software,
            1_000,
            10_000,
        )
        .unwrap();
        let bundle = OfflineTrustBundle::issue(
            &issuer,
            "field-replay",
            1,
            None,
            None,
            vec![credential],
            vec![],
        )
        .unwrap();
        let state_dir = std::env::temp_dir().join(format!(
            "openrtc-offline-replay-{}",
            crate::session_token::generate_nonce()
        ));
        std::fs::create_dir_all(&state_dir).unwrap();
        let state_path = state_dir.join("trust.json");
        let mut durable = DurableOfflineTrustState::open(
            &state_path,
            "field-replay",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .unwrap();
        durable.apply(bundle, 2_000).unwrap();
        let endpoint_addr = iroh::EndpointAddr::new(remote_endpoint)
            .with_ip_addr("127.0.0.1:4433".parse().unwrap());
        let candidate = durable
            .trust()
            .authorize_local_candidate("device-a", endpoint_addr, 2_000)
            .unwrap();
        let transcript = OfflineProofTranscript {
            protocol: OFFLINE_PROOF_PROTOCOL.into(),
            trust_domain: "field-replay".into(),
            credential_serial: "serial-replay".into(),
            presenter_device_id: "device-a".into(),
            presenter_endpoint_id: remote_endpoint.to_string(),
            verifier_device_id: "device-b".into(),
            verifier_endpoint_id: local_endpoint.to_string(),
            presenter_nonce: "presenter-restart".into(),
            verifier_nonce: "verifier-restart".into(),
            transport_stable_id: 9,
            channel_binding: "quic-exporter-generation-9".into(),
        };
        let proof = OfflineConnectionProof::create(&device, transcript.clone()).unwrap();
        let binding = OfflineTransportBinding {
            local_endpoint_id: local_endpoint.to_string(),
            remote_endpoint_id: remote_endpoint.to_string(),
            transport_stable_id: 9,
        };
        durable
            .verify_transport_proof(&candidate, &proof, &transcript, binding.clone(), 2_000)
            .unwrap();
        drop(durable);

        let mut restarted = DurableOfflineTrustState::open(
            &state_path,
            "field-replay",
            issuer.verifying_key().unwrap(),
            [],
            2_000,
        )
        .unwrap();
        let error = restarted
            .verify_transport_proof(&candidate, &proof, &transcript, binding, 2_000)
            .expect_err("accepted proof must remain consumed after restart")
            .to_string();
        assert!(error.contains("replay rejected"));
        std::fs::remove_dir_all(state_dir).unwrap();
    }

    #[cfg(all(not(target_arch = "wasm32"), feature = "transport-lan"))]
    #[test]
    fn local_candidate_proof_handoff_is_generation_and_replay_bound() {
        let issuer = SoftwareOfflineSigner::from_seed([1; 32]);
        let device = SoftwareOfflineSigner::from_seed([2; 32]);
        let local_endpoint = iroh::SecretKey::generate().public();
        let remote_endpoint = iroh::SecretKey::generate().public();
        let request = OfflineEnrollmentRequest::create(
            &device,
            "field-a",
            "device-a",
            &remote_endpoint.to_string(),
            "enroll-a",
            vec!["sensor".into()],
            OfflineAssurance::Software,
            1_000,
        )
        .unwrap();
        let credential = OfflineDeviceCredential::issue(
            &issuer,
            &request,
            "serial-a",
            1,
            vec!["sensor".into()],
            OfflineAssurance::Software,
            1_000,
            10_000,
        )
        .unwrap();
        let bundle =
            OfflineTrustBundle::issue(&issuer, "field-a", 1, None, None, vec![credential], vec![])
                .unwrap();
        let mut state = OfflineTrustState::new("field-a", issuer.verifying_key().unwrap()).unwrap();
        state.apply(bundle, 2_000).unwrap();
        let candidate = state
            .authorize_local_candidate(
                "device-a",
                iroh::EndpointAddr::new(remote_endpoint)
                    .with_ip_addr("127.0.0.1:4433".parse().unwrap()),
                2_000,
            )
            .unwrap();
        let transcript = OfflineProofTranscript {
            protocol: OFFLINE_PROOF_PROTOCOL.into(),
            trust_domain: "field-a".into(),
            credential_serial: "serial-a".into(),
            presenter_device_id: "device-a".into(),
            presenter_endpoint_id: remote_endpoint.to_string(),
            verifier_device_id: "device-b".into(),
            verifier_endpoint_id: local_endpoint.to_string(),
            presenter_nonce: "presenter-nonce".into(),
            verifier_nonce: "verifier-nonce".into(),
            transport_stable_id: 7,
            channel_binding: "quic-exporter-generation-7".into(),
        };
        let proof = OfflineConnectionProof::create(&device, transcript.clone()).unwrap();
        let binding = OfflineTransportBinding {
            local_endpoint_id: local_endpoint.to_string(),
            remote_endpoint_id: remote_endpoint.to_string(),
            transport_stable_id: 7,
        };
        let mut replay = OfflineReplayCache::new(8);
        let handoff = state
            .verify_transport_proof(
                &candidate,
                &proof,
                &transcript,
                binding.clone(),
                &mut replay,
                2_000,
            )
            .unwrap();
        assert_eq!(handoff.transport_stable_id(), 7);
        assert_eq!(handoff.device_id(), "device-a");
        assert!(state
            .verify_transport_proof(&candidate, &proof, &transcript, binding, &mut replay, 2_000,)
            .is_err());
        let stale_binding = OfflineTransportBinding {
            local_endpoint_id: local_endpoint.to_string(),
            remote_endpoint_id: remote_endpoint.to_string(),
            transport_stable_id: 8,
        };
        assert!(state
            .verify_transport_proof(
                &candidate,
                &proof,
                &transcript,
                stale_binding,
                &mut OfflineReplayCache::new(8),
                2_000,
            )
            .is_err());
    }

    #[test]
    fn bounded_swarm_never_projects_quadratic_degree() {
        let members = (0..100)
            .map(|index| format!("device-{index:03}"))
            .collect::<Vec<_>>();
        for local in &members {
            let neighbors = bounded_swarm_neighbors(local, members.clone(), 99).unwrap();
            assert_eq!(neighbors.len(), MAX_OFFLINE_SWARM_DEGREE);
            assert!(!neighbors.contains(local));
        }
    }
}