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+ForumApp is an application that uses [BSP](BSP) to synchronise invitation-only forums.
+
+### Channel identifiers
+
+ForumApp uses a channel with a random identifier for forum invitations:   
+`667e 2acb da80 2e61 3168 98f2 8ec5 8102 fcf2 3d10 04ee 3086 f5e9 94d8 30f5 b773`
+
+Each forum has its own channel with a hash identifier. The application data structure for generating the identifier is a [BDF](BDF) list with two elements: `forum_name` (string) and `salt` (raw, exactly HASH_LEN bytes). The random salt prevents collisions between forums with the same name. The application identifer is random:   
+`859a 7be5 0dca 035b 64bd 6902 fb79 7097 795a f837 abbf 8c16 d750 b3c2 ccc1 86ea`
+
+### Message types
+
+**0: INVITATION** - The content is a BDF list with two elements: `forum` (list) and `message` (string, may be null). `forum` is a list with two elements, `forum_name` and `salt`, as described above. `message` is an optional note from the inviter to the invitee.
+
+**1: RESPONSE** - The content is a BDF list with three elements: `invitation_id` (raw, exactly HASH_LEN bytes), `decision` (boolean), and `message` (string, may be null). `invitation_id` is the message identifier of the INVITATION to which this is a response. `decision` indicates whether the invitee wishes to join the forum. `message` is an optional note from the invitee to the inviter.
+
+**2: POST**
+
+**3: ATTACHMENT**
+
+### Validation
+
+### Storage policy
+
+### Sharing policy