diff --git a/BlogClient.markdown b/BlogClient.markdown
index 7c7eacd..45277e8 100644
--- a/BlogClient.markdown
+++ b/BlogClient.markdown
@@ -2,25 +2,24 @@ BlogClient is a [BSP client](BSP) that synchronises blog posts among groups of d
 
 ### Channel identifiers
 
-All blogs share a single invitation channel with the following random identifier:   
-`4f39 df93 e933 5027 9909 82bf 442f 7b40 75d3 b7f6 6139 34dd c6d1 b539 7a2a 65a3`
-
-Each blog has its own channel with a [hash identifier](BSP#channel-identifiers). The client data structure for generating the identifier is a [BDF](BDF) list with two elements: `name` (string) and `public_key` (raw).
-
-The client identifer is random:   
+BlogClient uses the following client identifer:   
 `dafb e56f 0c89 7136 5cea 4bb5 f08e c9a6 1d68 6e05 8b94 3997 b6ff 259b a423 f613`
 
+Each blog has its own channel, and there is a single invitation channel shared by all blogs. The [channel descriptor](BSP#channel-identifiers) for the invitation channel is an empty [BDF list](BDF).
+
+The channel descriptor for a blog channel is a list with two elements: `name` (string) and `public_key` (raw).
+
 ### Message types
 
-**0: INVITATION** - The content is a BDF list with two elements: `blog` (list) and `note` (string, may be null). `blog` is a list with two elements, `name` and `public_key`, as described above. `note` is an optional note from the inviter to the invitee.
+**0: INVITATION** - The content is a list with three elements: `name` (string), `public_key` (raw), and `note` (string or null). The channel identifier can be calculated from `name` and `public_key`, as described above. `note` is an optional note from the inviter to the invitee.
 
-**1: RESPONSE** - The content is a list with three elements: `invitation_id` (raw), `decision` (boolean), and `note` (string, may be 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.
+**1: RESPONSE** - The content is a 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 list with one element: `invitation_id` (raw), which is the identifier of an invitation created by either peer.
 
-**3: POST** - The content is a list with two elements: `content` (list) and `signature` (raw). `content` is a list with three elements: `parent_id` (raw, may be null), `body` (string), and `attachments` (dictionary, may be null). If `parent_id` is not null, it is the identifier of a post to which this is a follow-up. Each key in `attachments` is the name of an attachment, and the value is a list with two elements: `mime_type` (string) and `message_id` (raw).
+**3: POST** - The content is a list with two elements: `content` (list) and `signature` (raw). `content` is a list with three elements: `parent_id` (raw or null), `body` (string), and `attachments` (dictionary or null). `parent_id` is the identifier of a post to which this is a follow-up. Each key in `attachments` is the name of an attachment, and the value is a list with two elements: `mime_type` (string) and `message_id` (raw).
 
-`signature` is a signature with `public_key`, calculated over a list with four elements: `client_id` (raw), `blog` (list), `content` (list), and `timestamp` (int). `client_id` is the client identifier. `blog` and `content` are described above. `timestamp` is the timestamp from the [message header](BSP#message-format).
+`signature` is a signature over a list with three elements: `channel_id` (raw), `timestamp` (int), and `content` (list). `channel_id` and `timestamp` are taken from the [message header](BSP#message-format). `content` is described above.
 
 **4: ATTACHMENT** - The content is raw data.