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[WIP] Security work While on holiday

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Alex 2026-08-12 22:45:28 +02:00
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43
docs/PROTOCOL-REFERENCE.md
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@ -17,6 +17,47 @@ The client sends an MTP `Ping` communication value with a frame ID. The host ret
If automatic responses are disabled, the application must read Ping frames and send compatible Pong frames. Keepalive configuration is documented in the [native client](NATIVE-CLIENT.md) and [native host](NATIVE-HOST.md) guides.
## Relay metadata version
Protected relay metadata declares the reserved `RelayVersion` field as an unsigned integer. Builders currently emit version `1` automatically. Receivers select the metadata schema from this field before interpreting any version-specific fields. Missing versions are unsupported legacy relays, and unknown versions are rejected.
Relay format versions are independent of application type-map versions. A type-map version selects application-defined communication and data types. It does not select the protected relay metadata schema.
## Relay `CreatedAt`
The reserved `CreatedAt` field in relay metadata is an unsigned integer containing milliseconds elapsed since `1970-01-01T00:00:00Z`. It is not an ISO timestamp and it is not measured in seconds.
For example:
```text
2026-08-11T12:00:00.000Z
↓
Unix epoch milliseconds
↓
CreatedAt = 1786449600000
```
Native relay builders and browser relay senders use this unit. Verified browser metadata exposes `createdAt` as a `bigint`; native verified metadata exposes `u64`.
## Direct protected envelope
The high-level direct protected API signs an MTP-owned envelope before it is
encrypted for the recipient. Its reserved fields are `ProtectedVersion`,
`MessageType`, `FinalRecipientId`, `MessageId`, `CreatedAt`, and `Content`.
Receivers verify the envelope before dispatching application content and require
the signed message type and final recipient to match the outer communication
type and receiver. If the outer sender is present, it must match the signed
signer ID. `MessageId` and `CreatedAt` are authenticated; callers can pass a
replay guard to reject a previously accepted `(signerId, MessageId)` pair.
Native and browser replay guards both receive `CreatedAt` as authenticated
metadata, but the timestamp is not part of the replay key.
Verified SDK results expose the authenticated `protectedVersion` and
`finalRecipientId` alongside the application content.
Native applications use the same schema through `ProtectedMessageBuilder` and
`open_protected`; language bindings delegate envelope construction and opening
to this codec boundary.
## Authentication Flow
```text
@ -41,3 +82,5 @@ Login proof binds the protocol version, client ID, host challenge, and client no
## Version Negotiation
The client sends one compiled-in protocol version. The host compares it with the versions in its registry and returns the selected version in the opening response. Subsequent frames use that version's type map. An unsupported version closes the connection with `AcceptError::UnsupportedVersion`.
The self-delimiting `DataValue` codec and the three-bit communication header begin at protocol version `3.0`. A peer offering an older codec version is rejected during version negotiation; the new decoder does not attempt legacy flag, ID, or crypto-container fallbacks.