Fetch CAS blobs over Iroh

AGENTS.md

@@ -107,8 +107,9 @@ Roadmap items should be actionable and checkable:
   pinned `geth-iroh` endpoint wrapper with protocol-router scaffold, peer-card
   types, manual signed peer-card export/import/list commands, `geth peer ping`
   and `geth peer auth-check` over Iroh, signed peer-card LAN discovery payloads,
-  untrusted discovery-backend trait, custom relay-map config, and Iroh
-  local-network discovery toggle exist.
+  authorized `geth cas fetch` over the Iroh control ALPN, untrusted
+  discovery-backend trait, custom relay-map config, and Iroh local-network
+  discovery toggle exist.
 - Canonical signed-operation envelopes exist for keychain/auth signature
   payloads. The keychain reducer builds an active identity view for admin keys,
   users, devices, nodes, agents, and endpoint bindings.
@@ -120,7 +121,10 @@ Roadmap items should be actionable and checkable:
 - The daemon persists local keychain init/admin-key ops and reduces them for
   `keychain status`. SSH signature capture/verification is still roadmap work.
 - Local CAS supports pin/unpin metadata, surfaced through `cas list`, and
-  `cas cleanup` evicts unpinned blobs while retaining pinned blobs.
+  `cas cleanup` evicts unpinned blobs while retaining pinned blobs. The daemon
+  can fetch CAS blobs from an imported signed peer card over Iroh when the peer
+  grants `cas.fetch` on `resource:cas:local`; full `iroh-blobs` provider
+  integration is still roadmap work.
 - The CAS crate can build deterministic tree objects for local file trees and
   store those manifests as CAS blobs. The daemon can register and scan local
   file roots, reporting create/update/delete/rename changes without writing back
@@ -154,7 +158,6 @@ Roadmap items should be actionable and checkable:
   OpenSSH KRL files are not enumerable through OpenSSH tooling. Tests cover
   public-key and certificate binary KRL revocations when `ssh-keygen` is
   available.
-- Signed peer-card LAN discovery payloads, peer auth over Iroh, cr-sqlite,
-  iroh-docs, iroh-blobs, Automerge sync, broader auth enforcement, and
-  Keyhive/BeeKEM-style authorization are future roadmap items unless
-  implemented later.
+- cr-sqlite, iroh-docs, iroh-blobs provider/fetch, Automerge sync, broader auth
+  enforcement, and Keyhive/BeeKEM-style authorization are future roadmap items
+  unless implemented later.

Cargo.lock

@@ -1229,6 +1229,7 @@ dependencies = [
 name = "geth-node"
 version = "0.1.0"
 dependencies = [
+ "base64",
  "geth-auth",
  "geth-cas",
  "geth-config",

README.md

@@ -91,8 +91,8 @@ The bootstrap implementation provides:
 - `geth auth explain <subject> <resource> <capability>`
 - `geth auth grant <subject> <resource> <capability> [--grant-id <id>]`
 - `geth auth revoke <resource> <grant-id>`
-- local filesystem CAS commands: `add`, `get`, `hash`, `has`, `pin`, `unpin`,
-  `cleanup`, `list`
+- local filesystem CAS commands: `add`, `get`, `fetch`, `hash`, `has`, `pin`,
+  `unpin`, `cleanup`, `list`
 - local CAS tree objects describe file trees and are stored as CAS blobs
 - local file-root commands: `geth cas root add/list/scan`
 - local file conflict metadata commands:
@@ -125,6 +125,12 @@ imported peer card and exchange a signed candidate-only peer-card ping.
 `geth peer auth-check <node-id> <resource> <capability>` sends a protected
 Iroh control request: the remote daemon verifies that the caller's signed peer
 card binds the actual Iroh EndpointID before reducing resource-local auth ops.
+`geth cas fetch <node-id> <hash>` uses the same protected Iroh control path to
+request a blob from a peer. The remote daemon only returns bytes when the caller
+has `cas.fetch` on `resource:cas:local`, and the caller verifies that the bytes
+hash to the requested BLAKE3 CAS hash before storing them locally. This is the
+bootstrap transfer path; future work will move provider/fetch behavior to
+`iroh-blobs`.
 Importing or pinging a peer card never grants capabilities by itself.
 When `[iroh].local_discovery = true`, the daemon also advertises and discovers
 signed peer cards on LAN using a geth-specific mDNS TXT payload. That payload is

crates/geth-cas/src/lib.rs

@@ -244,6 +244,14 @@ impl LocalCas {
         std::fs::copy(path, out).map_err(CasError::from)
     }
 
+    pub fn read_bytes(&self, hash: &BlobHash) -> Result<Vec<u8>, CasError> {
+        let path = self.blob_path(hash)?;
+        if !path.exists() {
+            return Err(CasError::NotFound(hash.to_string()));
+        }
+        Ok(std::fs::read(path)?)
+    }
+
     pub fn has(&self, hash: &BlobHash) -> Result<bool, CasError> {
         Ok(self.blob_path(hash)?.exists())
     }
@@ -547,6 +555,10 @@ mod tests {
         let out = dir.path().join("out.txt");
         cas.get_to_path(&info.hash, &out).expect("get");
         assert_eq!(std::fs::read(out).expect("read"), b"hello geth");
+        assert_eq!(
+            cas.read_bytes(&info.hash).expect("read bytes"),
+            b"hello geth"
+        );
     }
 
     #[test]

crates/geth-cli/src/lib.rs

@@ -223,6 +223,10 @@ pub enum CasCommand {
         #[arg(long)]
         out: PathBuf,
     },
+    Fetch {
+        node: String,
+        hash: String,
+    },
     Hash {
         path: PathBuf,
     },
@@ -548,6 +552,10 @@ fn request_for_command(command: Command) -> Result<ControlRequest> {
                 hash: hash.into(),
                 out,
             },
+            CasCommand::Fetch { node, hash } => ControlRequest::CasFetch {
+                node,
+                hash: hash.into(),
+            },
             CasCommand::Hash { path } => ControlRequest::CasHash { path },
             CasCommand::Has { hash } => ControlRequest::CasHas { hash: hash.into() },
             CasCommand::Pin { hash } => ControlRequest::CasPin { hash: hash.into() },
@@ -879,6 +887,27 @@ fn print_response(response: ControlResponse, json: bool) -> Result<()> {
         } => {
             println!("wrote {hash} to {} ({size_bytes} bytes)", out.display());
         }
+        ControlResponse::CasFetched {
+            peer_node_id,
+            peer_agent_id,
+            endpoint_id,
+            hash,
+            size_bytes,
+            allowed,
+            reason,
+            note,
+        } => {
+            if allowed {
+                println!("fetched {hash} from {peer_node_id} ({size_bytes} bytes)");
+            } else {
+                println!("fetch denied for {hash} from {peer_node_id}");
+            }
+            println!("agent: {peer_agent_id}");
+            println!("endpoint: {endpoint_id}");
+            println!("allowed: {allowed}");
+            println!("reason: {reason}");
+            println!("note: {note}");
+        }
         ControlResponse::CasHash { hash } => println!("{hash}"),
         ControlResponse::CasHas { hash, present } => println!("{hash}: {present}"),
         ControlResponse::CasPinned { hash, pinned } => {

crates/geth-control/src/lib.rs

@@ -48,6 +48,10 @@ pub enum ControlRequest {
         hash: BlobHash,
         out: PathBuf,
     },
+    CasFetch {
+        node: String,
+        hash: BlobHash,
+    },
     CasHash {
         path: PathBuf,
     },
@@ -269,6 +273,16 @@ pub enum ControlResponse {
         out: PathBuf,
         size_bytes: u64,
     },
+    CasFetched {
+        peer_node_id: String,
+        peer_agent_id: String,
+        endpoint_id: String,
+        hash: BlobHash,
+        size_bytes: u64,
+        allowed: bool,
+        reason: String,
+        note: String,
+    },
     CasHash {
         hash: BlobHash,
     },
@@ -467,6 +481,11 @@ pub enum PeerControlRequest {
         capability: String,
         nonce: String,
     },
+    CasFetch {
+        peer_card: PeerCard,
+        hash: BlobHash,
+        nonce: String,
+    },
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -494,6 +513,20 @@ pub enum PeerControlResponse {
         nonce: String,
         note: String,
     },
+    CasFetched {
+        node_id: String,
+        agent_id: String,
+        endpoint_id: String,
+        remote_endpoint_id: String,
+        hash: BlobHash,
+        size_bytes: u64,
+        content_base64: Option<String>,
+        allowed: bool,
+        reason: String,
+        evaluated_ops: usize,
+        nonce: String,
+        note: String,
+    },
     Error {
         message: String,
     },
@@ -568,6 +601,15 @@ mod tests {
             response
         );
 
+        let request = ControlRequest::CasFetch {
+            node: "node:peer".to_owned(),
+            hash: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef".into(),
+        };
+        assert_eq!(
+            decode_request(&encode_request(&request).expect("encode")).expect("decode"),
+            request
+        );
+
         let request = ControlRequest::SshRevocationExport {
             out: PathBuf::from("revocations.krl-spec"),
             format: "openssh-krl-spec".to_owned(),
@@ -700,5 +742,25 @@ mod tests {
                 .expect("decode"),
             response
         );
+
+        let response = PeerControlResponse::CasFetched {
+            node_id: "node:peer".to_owned(),
+            agent_id: "agent:peer".to_owned(),
+            endpoint_id: "endpoint:peer".to_owned(),
+            remote_endpoint_id: "endpoint:caller".to_owned(),
+            hash: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef".into(),
+            size_bytes: 5,
+            content_base64: Some("aGVsbG8".to_owned()),
+            allowed: true,
+            reason: "direct grant".to_owned(),
+            evaluated_ops: 1,
+            nonce: "nonce".to_owned(),
+            note: "cas fetch".to_owned(),
+        };
+        assert_eq!(
+            decode_peer_response(&encode_peer_response(&response).expect("encode"))
+                .expect("decode"),
+            response
+        );
     }
 }

crates/geth-node/Cargo.toml

@@ -6,6 +6,7 @@ rust-version.workspace = true
 license.workspace = true
 
 [dependencies]
+base64.workspace = true
 serde_json.workspace = true
 thiserror.workspace = true
 tokio.workspace = true

crates/geth-node/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod service;
 
+use base64::Engine;
 use geth_auth::{AuthExplanation, AuthOp, AuthOpKind};
 use geth_cas::{
     BlobInfoSummary, FileConflict, FileConflictKind, FileConflictResolution, FileConflictStatus,
@@ -36,8 +37,8 @@ use geth_store::{
     StoredResourceSecret, StoredSshCertRequest, StoredSshCertificate, StoredSshRevocation,
 };
 use geth_types::{
-    AuthOpId, Capability, KeyId, NodeId, PrincipalId, ResourceId, ResourceKind, ResourceName,
-    SshCertId, SshCertRequestId, UnixMillis,
+    AuthOpId, BlobHash, Capability, KeyId, NodeId, PrincipalId, ResourceId, ResourceKind,
+    ResourceName, SshCertId, SshCertRequestId, UnixMillis,
 };
 use std::collections::{BTreeMap, VecDeque};
 use std::path::Path;
@@ -239,6 +240,10 @@ pub async fn handle_request_async(
             resource,
             capability,
         } => peer_auth_check(node, &peer_node, resource, capability).await,
+        ControlRequest::CasFetch {
+            node: peer_node,
+            hash,
+        } => cas_fetch_from_peer(node, &peer_node, hash).await,
         other => handle_request(node, other),
     }
 }
@@ -512,6 +517,9 @@ async fn peer_ping(node: &LocalNode, peer_node: &str) -> Result<ControlResponse,
         PeerControlResponse::AuthChecked { .. } => Err(NodeError::IrohPeer(
             "peer returned auth-check response to ping request".to_owned(),
         )),
+        PeerControlResponse::CasFetched { .. } => Err(NodeError::IrohPeer(
+            "peer returned CAS fetch response to ping request".to_owned(),
+        )),
     }
 }
 
@@ -614,6 +622,142 @@ async fn peer_auth_check(
         PeerControlResponse::Pong { .. } => Err(NodeError::IrohPeer(
             "peer returned pong to auth-check request".to_owned(),
         )),
+        PeerControlResponse::CasFetched { .. } => Err(NodeError::IrohPeer(
+            "peer returned CAS fetch response to auth-check request".to_owned(),
+        )),
+    }
+}
+
+async fn cas_fetch_from_peer(
+    node: &LocalNode,
+    peer_node: &str,
+    hash: BlobHash,
+) -> Result<ControlResponse, NodeError> {
+    let store = Store::open(&node.paths.metadata_db())?;
+    let stored = store
+        .get_peer_card(peer_node)?
+        .ok_or_else(|| NodeError::PeerNotFound(peer_node.to_owned()))?;
+    let peer_card: PeerCard = serde_json::from_str(&stored.card_json)?;
+    peer_card.validate_candidate()?;
+    let candidate = peer_card
+        .endpoints
+        .first()
+        .ok_or(geth_discovery::DiscoveryError::MissingEndpoint)?;
+    ensure_peer_card_matches_endpoint(&peer_card, &candidate.endpoint_id)?;
+    let node_addr = iroh_node_addr_from_candidate(candidate)?;
+    let endpoint = node
+        .iroh_endpoint
+        .lock()
+        .map_err(|_| NodeError::RuntimeLockPoisoned)?
+        .clone()
+        .ok_or(NodeError::IrohEndpointUnavailable)?;
+    let self_card = local_peer_card(node, DiscoverySource::PeerExchange, true).await?;
+    let nonce = geth_crypto::blake3_hex(
+        format!(
+            "{}\0{}\0{}\0{}",
+            node.node_id,
+            peer_node,
+            hash.as_str(),
+            geth_store::now_ms()
+        )
+        .as_bytes(),
+    );
+    let request = PeerControlRequest::CasFetch {
+        peer_card: self_card,
+        hash: hash.clone(),
+        nonce: nonce.clone(),
+    };
+
+    let conn = endpoint
+        .endpoint()
+        .connect(node_addr, geth_iroh::ALPN_CONTROL)
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let (mut send, mut recv) = conn
+        .open_bi()
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    send.write_all(geth_control::encode_peer_request(&request)?.as_bytes())
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    send.finish()
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let bytes = recv
+        .read_to_end(64 * 1024 * 1024)
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let text =
+        std::str::from_utf8(&bytes).map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    match geth_control::decode_peer_response(text)? {
+        PeerControlResponse::CasFetched {
+            node_id,
+            agent_id,
+            endpoint_id,
+            hash: response_hash,
+            size_bytes,
+            content_base64,
+            allowed,
+            reason,
+            nonce: response_nonce,
+            note,
+            ..
+        } if response_nonce == nonce && response_hash == hash => {
+            if !allowed {
+                return Ok(ControlResponse::CasFetched {
+                    peer_node_id: node_id,
+                    peer_agent_id: agent_id,
+                    endpoint_id,
+                    hash: response_hash,
+                    size_bytes: 0,
+                    allowed,
+                    reason,
+                    note,
+                });
+            }
+            let content = content_base64
+                .ok_or_else(|| NodeError::IrohPeer("peer omitted CAS content".to_owned()))
+                .and_then(|content| {
+                    base64::engine::general_purpose::STANDARD
+                        .decode(content)
+                        .map_err(|error| NodeError::IrohPeer(error.to_string()))
+                })?;
+            if content.len() as u64 != size_bytes {
+                return Err(NodeError::IrohPeer(format!(
+                    "peer announced {size_bytes} CAS bytes but returned {} bytes",
+                    content.len()
+                )));
+            }
+            let cas = LocalCas::new(node.paths.cas_dir());
+            let info = cas.add_bytes(&content)?;
+            if info.hash != response_hash {
+                return Err(NodeError::IrohPeer(format!(
+                    "peer returned content hash {} for requested {}",
+                    info.hash, response_hash
+                )));
+            }
+            store.record_cas_object(
+                info.hash.as_str(),
+                info.size_bytes,
+                &info.path.to_string_lossy(),
+            )?;
+            Ok(ControlResponse::CasFetched {
+                peer_node_id: node_id,
+                peer_agent_id: agent_id,
+                endpoint_id,
+                hash: info.hash,
+                size_bytes: info.size_bytes,
+                allowed,
+                reason,
+                note,
+            })
+        }
+        PeerControlResponse::CasFetched { .. } => Err(NodeError::IrohPeer(
+            "peer CAS fetch response did not match request".to_owned(),
+        )),
+        PeerControlResponse::Error { message } => Err(NodeError::IrohPeer(message)),
+        PeerControlResponse::Pong { .. } | PeerControlResponse::AuthChecked { .. } => Err(
+            NodeError::IrohPeer("peer returned wrong response type to CAS fetch".to_owned()),
+        ),
     }
 }
 
@@ -720,6 +864,74 @@ async fn handle_iroh_control_connection(
                 note: "protected peer request authenticated endpoint/card binding before resource capability evaluation".to_owned(),
             }
         }
+        PeerControlRequest::CasFetch {
+            peer_card,
+            hash,
+            nonce,
+        } => {
+            peer_card.validate_candidate()?;
+            ensure_peer_card_matches_endpoint(&peer_card, &remote_endpoint_id)?;
+            let discovered = DiscoveredPeer::candidate(
+                peer_card.clone(),
+                UnixMillis(geth_store::now_ms()),
+                DiscoverySource::PeerExchange,
+            )?;
+            let store = Store::open(&node.paths.metadata_db())?;
+            store.upsert_peer_card(&StoredPeerCard {
+                peer_id: peer_card.node_id.to_string(),
+                card_json: serde_json::to_string(&peer_card)?,
+                updated_at_ms: discovered.discovered_at.0,
+            })?;
+            let resource = "resource:cas:local".to_owned();
+            let capability = "cas.fetch".to_owned();
+            let explanation = geth_auth::explain_auth_ops(
+                &load_auth_ops_for_resource(&store, &resource)?,
+                PrincipalId::new(peer_card.node_id.to_string()),
+                ResourceId::new(resource),
+                Capability::new(capability),
+            );
+            if explanation.allowed {
+                match LocalCas::new(node.paths.cas_dir()).read_bytes(&hash) {
+                    Ok(content) => {
+                        let size_bytes = content.len() as u64;
+                        PeerControlResponse::CasFetched {
+                            node_id: node.node_id.clone(),
+                            agent_id: node.agent_id.clone(),
+                            endpoint_id: node.iroh_status.endpoint_id.clone().unwrap_or_default(),
+                            remote_endpoint_id,
+                            hash,
+                            size_bytes,
+                            content_base64: Some(
+                                base64::engine::general_purpose::STANDARD.encode(content),
+                            ),
+                            allowed: true,
+                            reason: explanation.reason,
+                            evaluated_ops: explanation.evaluated_ops,
+                            nonce,
+                            note: "CAS fetch authenticated endpoint/card binding and required cas.fetch on resource:cas:local".to_owned(),
+                        }
+                    }
+                    Err(error) => PeerControlResponse::Error {
+                        message: format!("CAS blob {hash} is not available: {error}"),
+                    },
+                }
+            } else {
+                PeerControlResponse::CasFetched {
+                    node_id: node.node_id.clone(),
+                    agent_id: node.agent_id.clone(),
+                    endpoint_id: node.iroh_status.endpoint_id.clone().unwrap_or_default(),
+                    remote_endpoint_id,
+                    hash,
+                    size_bytes: 0,
+                    content_base64: None,
+                    allowed: false,
+                    reason: explanation.reason,
+                    evaluated_ops: explanation.evaluated_ops,
+                    nonce,
+                    note: "CAS fetch authenticated endpoint/card binding and required cas.fetch on resource:cas:local".to_owned(),
+                }
+            }
+        }
     };
     send.write_all(geth_control::encode_peer_response(&response)?.as_bytes())
         .await
@@ -855,6 +1067,7 @@ pub fn handle_request(
         }
         ControlRequest::PeerPing { .. } => Err(NodeError::IrohEndpointUnavailable),
         ControlRequest::PeerAuthCheck { .. } => Err(NodeError::IrohEndpointUnavailable),
+        ControlRequest::CasFetch { .. } => Err(NodeError::IrohEndpointUnavailable),
         ControlRequest::ResourceList => Ok(ControlResponse::ResourceList {
             resources: store
                 .list_resources()?
@@ -2330,6 +2543,9 @@ mod tests {
                 updated_at_ms: geth_store::now_ms(),
             })
             .expect("insert right peer");
+        let right_blob = LocalCas::new(right.paths.cas_dir())
+            .add_bytes(b"remote cas bytes")
+            .expect("right cas add");
 
         let ping = handle_request_async(
             &left,
@@ -2380,6 +2596,34 @@ mod tests {
             other => panic!("unexpected denied auth response: {other:?}"),
         }
 
+        let denied_fetch = handle_request_async(
+            &left,
+            ControlRequest::CasFetch {
+                node: right_card.node_id.to_string(),
+                hash: right_blob.hash.clone(),
+            },
+        )
+        .await
+        .expect("denied cas fetch");
+        match denied_fetch {
+            ControlResponse::CasFetched {
+                allowed,
+                reason,
+                size_bytes,
+                ..
+            } => {
+                assert!(!allowed);
+                assert_eq!(size_bytes, 0);
+                assert!(reason.contains("no active direct or group grant"));
+                assert!(
+                    !LocalCas::new(left.paths.cas_dir())
+                        .has(&right_blob.hash)
+                        .expect("left cas has after denied fetch")
+                );
+            }
+            other => panic!("unexpected denied CAS fetch response: {other:?}"),
+        }
+
         handle_request(
             &right,
             ControlRequest::AuthGrant {
@@ -2415,6 +2659,39 @@ mod tests {
             other => panic!("unexpected allowed auth response: {other:?}"),
         }
 
+        let fetched = handle_request_async(
+            &left,
+            ControlRequest::CasFetch {
+                node: right_card.node_id.to_string(),
+                hash: right_blob.hash.clone(),
+            },
+        )
+        .await
+        .expect("allowed cas fetch");
+        match fetched {
+            ControlResponse::CasFetched {
+                allowed,
+                hash,
+                size_bytes,
+                reason,
+                note,
+                ..
+            } => {
+                assert!(allowed);
+                assert_eq!(hash, right_blob.hash);
+                assert_eq!(size_bytes, right_blob.size_bytes);
+                assert!(reason.contains("direct grant"));
+                assert!(note.contains("required cas.fetch"));
+                assert_eq!(
+                    LocalCas::new(left.paths.cas_dir())
+                        .read_bytes(&right_blob.hash)
+                        .expect("left cas read fetched blob"),
+                    b"remote cas bytes"
+                );
+            }
+            other => panic!("unexpected allowed CAS fetch response: {other:?}"),
+        }
+
         left_endpoint.shutdown().await;
         right_endpoint.shutdown().await;
     }

docs/architecture.md

@@ -111,9 +111,16 @@ into CAS tree objects while reporting create/update/delete/rename changes. These
 scans are local metadata only and never overwrite the working tree. The daemon
 also has durable local file-conflict records with explicit resolution choices;
 future cross-node file sync will create those records automatically instead of
-silently applying ambiguous remote changes. Iroh-blobs, providers, encrypted
-blobs, richer cache policies, cross-node file roots, and automatic conflict
-detection are future work.
+silently applying ambiguous remote changes.
+
+As a bootstrap network path, `geth cas fetch <node-id> <hash>` dials an
+imported signed peer card over the daemon-owned Iroh control ALPN. The serving
+daemon validates the caller's peer-card signature and observed Iroh EndpointID,
+then reduces local auth ops and requires `cas.fetch` on `resource:cas:local`
+before returning blob bytes. The requester verifies that the returned bytes hash
+to the requested BLAKE3 CAS hash before storing them. Iroh-blobs, provider
+tracking, encrypted blobs, richer cache policies, cross-node file roots, and
+automatic conflict detection are future work.
 
 `geth-db` currently registers local SQLite paths as DB resources and reports
 local-only sync status plus a read-only SQLite schema summary/hash. It also

docs/roadmap.md

@@ -218,11 +218,19 @@ resource-scoped capability decisions.
 Goal: turn local CAS and stubs into Iroh-backed replicated modules while keeping
 authorization and durable-state boundaries clear.
 
-- `[ ]` Iroh-blobs CAS integration.
+- `[~]` Iroh-blobs CAS integration.
   Acceptance criteria:
-  - Local CAS can provide and fetch blobs over Iroh.
-  - Provider tracking is recorded locally.
-  - Local add/get/hash/has/list behavior remains backward compatible.
+  - `[x]` `geth cas fetch <node-id> <hash>` can fetch a blob from an imported
+    peer over the daemon-owned Iroh control ALPN.
+  - `[x]` The serving peer validates the caller's signed peer card against the
+    observed Iroh EndpointID before considering authorization.
+  - `[x]` Remote CAS fetch requires `cas.fetch` on `resource:cas:local`.
+  - `[x]` The requester verifies returned bytes against the requested BLAKE3
+    CAS hash before storing them locally.
+  - `[x]` Local add/get/hash/has/list behavior remains backward compatible.
+  - `[ ]` Replace the bootstrap control-ALPN transfer with `iroh-blobs`
+    provider/fetch behavior.
+  - `[ ]` Provider tracking is recorded locally.
 
 - `[x]` CAS pin and cache policy.
   Acceptance criteria: