Kaladaran/briar
0
0
Fork 0
mirror of https://code.briarproject.org/briar/briar.git synced 2026-02-12 18:59:06 +01:00
Code Issues Projects Releases Wiki Activity

Update ForumClient

akwizgran
2018-03-22 13:06:08 +00:00
parent 3fcf199e23
commit a9b2cbaa39
1 changed files with 8 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
ForumClient.md

@@ -1,64 +1,25 @@
ForumClient is a [BSP client](BSP) that synchronises forum posts among groups of devices. Any subscriber to a forum can invite new subscribers, and any subscriber can post to the forum. Posts may be anonymous or signed.
> Implementation note: We propose to use Ed25519 for signatures.
The forum clisn is a [BSP client](BSP) that synchronises forum posts among groups of devices. Any subscriber can post to a forum. Posts are signed by their authors.
### Group identifiers
ForumClient uses the following client identifer:
`859a 7be5 0dca 035b 64bd 6902 fb79 7097 795a f837 abbf 8c16 d750 b3c2 ccc1 86ea`
The forum client's identifier is `org.briarproject.briar.forum`.
Each forum has its own group. The [group descriptor](BSP#group-identifiers) is a [BDF list](BDF) with two elements: `title` (string) and `salt` (raw). The salt is HASH_LEN random bytes, to prevent collisions between forums with the same title.
For exchanging invitations, the client uses a separate group for each pair of contacts. The group descriptor is a BDF list containing the unique IDs of the contacts' identities, sorted in ascending order as byte strings.
Each forum has its own group. The [group descriptor](BSP#group-identifiers) is a [BDF list](BDF) with two elements: `name` (string) and `salt` (raw). The salt is 32 random bytes, to prevent collisions between forums with the same name.
### Message types
**0: INVITATION** - The content is a BDF list with three elements: `title` (string), `salt` (raw), and `note` (string or null). The identifier of the forum group to which the invitation refers can be calculated from `title` and `salt`, as described above. `note` is an optional note from the inviter to the invitee.
**POST** - The content is a BDF list with four elements: `parentId` (unique ID or null), `author` (list), `content` (string), and `signature` (raw).
**1: RESPONSE** - The content is a BDF list with three elements: `invitation_id` (raw), `decision` (boolean), and `note` (string or null). `invitation_id` is the identifier of an invitation created by the opposite peer. `decision` indicates whether the invitee wishes to subscribe. `note` is an optional note from the invitee to the inviter.
**2: DEPARTURE** - The content is a BDF list with one element: `invitation_id` (raw), which is the identifier of an invitation created by either peer.
**3: POST** - The content is a BDF list with three elements: `author` (list or null), `content` (list), and `signature` (raw or null).
`author` is a list with two elements: `name` (string) and `public_key` (raw).
`content` is a list with three elements: `parent_id` (raw or null), `content_type` (string), `body` (raw), and `attachments` (dictionary or null). `parent_id` is the identifier of a post to which this is a response. Each key in `attachments` is the name of an attachment, and the value is a list with two elements: `content_type` (string) and `message_id` (raw).
`signature` is a signature over a list with five elements: `group_id` (raw), `timestamp` (int), `author` (list), and `content` (list). `group_id` and `timestamp` are taken from the [message header](BSP#message-format). `author` and `content` are described above.
If `author` and `signature` are null, the post is anonymous.
**4: ATTACHMENT** - The content is raw data.
`parentId` is the optional ID of a post in the same group to which this post replies. `author` is a list with three elements: `formatVersion` (int), `nickname` (string), and `publicKey` (raw). The signature covers a BDF list with five elements: `groupId` (unique ID), `timestamp` (int), `parentId` (unique ID or null), `author` (list), and `content` (string). The group ID and timestamp are taken from the message header.
### Validity policy
* An invitation or response must belong to an invitation group.
* A post or attachment must belong to a forum group.
* An invitation is valid if it is well-formed.
* A response is valid if it is well-formed and it references a valid invitation created by the opposite peer.
* A departure is valid if it is well-formed and it references a valid invitation created by either peer.
* A post is valid if it is well-formed, its parent (if any) is a valid post, and it is either anonymous or carries a valid signature.
* An attachment is always valid.
Note that a post can be validated before its attachments have been received, and an attachment can be validated before it has been completely received.
* A post is valid if it is well-formed, has a valid signature, and its parent (if any) is valid.
### Storage policy
For invitation groups:
* All local messages are stored.
* All remote messages are stored.
For forum groups:
* All local messages are stored.
* All remote messages are stored.
* All messages are stored.
### Sharing policy
For invitation groups:
* All local messages are shared.
* All remote messages are shared.
For forum groups:
* All local messages are shared.
* All remote messages are shared.
* All messages are shared.