<p>As far as I understand the process the channel is constructed between two peers. For privacy reasons one of the two peers could decide to keep the channel private.</p>

<p><a href="https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#the-announcement_signatures-message" rel="nofollow noreferrer">Bolt7</a> uses the following quote with a reference to the <a href="https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md#the-open_channel-message" rel="nofollow noreferrer">open message of Bolt2</a></p>

<blockquote>
  <p>The willingness of the initiating node to announce the channel is signaled during channel opening by setting the announce_channel bit in channel_flags (see <a href="https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md#the-open_channel-message" rel="nofollow noreferrer">BOLT #2</a>).</p>
</blockquote>

<p>In that case the peer would not sign the channel and disalowing the other party to have a <code>channel_announcement</code> message. In this way the channel cannot be public as others would not react to the announcement as there are signatures missing. </p>

<p>So to summarize: the message with the signatures is a message between the channel partners allowing for a gossip message of the peer2peer protocol to announce the channel. Hope that made it clear (:</p>

CC BY-SA 4.0
2018-10-11T12:55:12.477Z
2018-10-11T12:55:12.477Z
Rene Pickhardt
<p>Isn't the <code>channel_announcement</code> message enough for channel advertisement? Why is the <code>announcement_signatures</code> message required?</p>

<p>Reference <a href="https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#the-announcement_signatures-message" rel="nofollow noreferrer">BOLT #7</a></p>

<lightning-network><lightning-routing><ln-gossip>
What is the purpose of the announcement_signatures message as specified by the Lightning Network RFC?
Samvid
# What is the purpose of the announcement_signatures message as specified by the Lightning Network RFC?

(Asked by: username_0 on 2018-10-11)

Isn't the `channel_announcement` message enough for channel advertisement? Why is the `announcement_signatures` message required?

Reference [BOLT #7](https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#the-announcement_signatures-message)

**Tags:** lightning-network, lightning-routing, ln-gossip


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## 1 answers

### Answer by username_1 on 2018-10-11. Score: 3 | Accepted answer

As far as I understand the process the channel is constructed between two peers. For privacy reasons one of the two peers could decide to keep the channel private.

[Bolt7](https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#the-announcement_signatures-message) uses the following quote with a reference to the [open message of Bolt2](https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md#the-open_channel-message)

> The willingness of the initiating node to announce the channel is signaled during channel opening by setting the announce\_channel bit in channel\_flags (see [BOLT #2](https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md#the-open_channel-message)).

In that case the peer would not sign the channel and disalowing the other party to have a `channel_announcement` message. In this way the channel cannot be public as others would not react to the announcement as there are signatures missing.

So to summarize: the message with the signatures is a message between the channel partners allowing for a gossip message of the peer2peer protocol to announce the channel. Hope that made it clear (:


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