Struct ProjectedContext 

pub struct ProjectedContext { /* private fields */ }

A broadcast context whose messages are projected (decrypted and served) by this node’s HTTP endpoints.

Maps epoch numbers to their corresponding BroadcastKeys so the projection handlers can decrypt messages from any epoch the node has observed. Multiple epochs are retained for the blob TTL window so messages encrypted under previous keys can still be decrypted.

Stores the context’s BroadcastAdmission mode and optional ProjectionPolicy so projection handlers can enforce authentication requirements (SCP-GG-007, SCP-GG-008).

See spec section 18.11.5.

Implementations

impl ProjectedContext

pub fn new( context_id: &str, broadcast_key: BroadcastKey, admission: BroadcastAdmission, projection_policy: Option<ProjectionPolicy>, ) -> Self

Creates a new ProjectedContext from a context ID, initial broadcast key, admission mode, and optional projection policy.

The routing ID is computed as SHA-256(context_id) per spec section 5.14.6. The key is inserted at its own epoch number. The admission mode and projection policy are stored for use by projection handlers when deciding whether to require authentication (spec section 18.11.2.1).

pub const fn routing_id(&self) -> &[u8; 32]

Returns the routing ID for this projected context.

pub fn context_id(&self) -> &str

Returns the context ID (hex-encoded string).

pub const fn keys(&self) -> &HashMap<u64, BroadcastKey>

Returns a reference to the keys map (epoch -> broadcast key).

pub const fn admission(&self) -> BroadcastAdmission

Returns the admission mode for this broadcast context.

pub const fn projection_policy(&self) -> Option<&ProjectionPolicy>

Returns the projection policy, if any.

pub fn insert_key(&mut self, broadcast_key: BroadcastKey)

Inserts a broadcast key for the given epoch.

Keys are retained indefinitely rather than pruned after the blob TTL window (spec §18.11.5). This is acceptable because:

• Key rotations only occur on subscriber blocks (uncommon)
• Each key is ~40 bytes (32-byte secret + epoch + author DID ref)
• Even hundreds of epochs per context is negligible memory

If pruning becomes necessary, add a prune_before(epoch) method keyed to the relay’s max_blob_ttl.

Important: After a governance ban (RevokeReadAccess / governance_ban_subscriber), all author keys are rotated in the ContextManager. The caller MUST propagate the new-epoch keys to the projection registry via this method; otherwise the projection endpoint cannot decrypt content encrypted under the new keys.

pub fn retain_only_epochs(&mut self, epochs: &HashSet<u64>)

Removes all keys whose epoch is NOT in the given set.

Used after a Full-scope governance ban to ensure historical content encrypted under pre-ban keys is no longer decryptable by the projection endpoint. Messages referencing purged epochs will return 410 Gone rather than serving content that a banned subscriber may have previously accessed.

Takes a set of epochs to retain (typically the new post-rotation epochs). This correctly handles epoch-divergent multi-author contexts where authors may be at different epochs.

pub fn key_for_epoch(&self, epoch: u64) -> Option<&BroadcastKey>

Returns the broadcast key for the given epoch, if present.

Trait Implementations

impl Debug for ProjectedContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.