<p>Yes and no: this is a presentation from 2015, and you are referencing a section which Pieter described as "assume we can redesign bitcoin". So bitcoin hasn't been redesigned, and not everything has been implemented as described in 6:20. </p>

<p>How it is handled today is part of a discussion <a href="https://bitcointalk.org/index.php?topic=1682183.msg21389041#msg21389041" rel="nofollow noreferrer">with Andrew in bitcointalk</a> (read down to page end). Older nodes don't get to see the witness data. They get just tx data, in an "anyone can spend" way, so it is recognized as valid tx by older nodes. Newer nodes get the witness data (of course). </p>

<blockquote>
  <p>Am i right saying that signatures for segwit outputs will never be
  relayed to old clients?</p>
</blockquote>

<p>yes.</p>

CC BY-SA 3.0
2018-03-06T16:52:00.090Z
2018-03-06T16:52:00.090Z
pebwindkraft
<p>When nodes connect, they introduce themselves to each other by telling each other their service flags. One of these service flags, <code>NODE_WITNESS</code>, informs their counterpart whether a node is segwit-capable. Only nodes that set <code>NODE_WITNESS</code> will receive the full transaction, other peers will be sent the stripped transaction without the witness data.</p>
<p>Note that <code>NODE_WITNESS</code> was <a href="https://github.com/bitcoin/bitcoin/commit/b8a97498df1e83f8dcc49bc3fa4344f9e9799242" rel="nofollow noreferrer">introduced in the 0.13-branch</a> of Bitcoin Core. This means that the last non-segwit version of Bitcoin Core has been End of Life since at least 2018.</p>

CC BY-SA 4.0
2022-03-10T04:34:49.910Z
If an old peer receives, then rebroadcasts that transaction, won't the rebroadcast transaction be useless since it doesn't have the witness data? Wouldn't it be dropped as invalid by the first segwit node that gets it?
B T
CC BY-SA 4.0
2022-03-10T10:47:37.130Z
@BT: Segwit nodes will never ask non-segwit nodes for transactions.
Murch
CC BY-SA 4.0
2018-03-06T17:54:50.633Z
2022-04-20T17:42:50.787Z
2022-04-20T17:42:50.787Z
Murch
<p>In the process of trying to understand the effects of segwit on Bitcoin I started watching this:</p>

<p><a href="https://www.youtube.com/watch?v=NOYNZB5BCHM" rel="nofollow noreferrer">https://www.youtube.com/watch?v=NOYNZB5BCHM</a></p>

<p>Which are the cases in which the receiver does not need the signatures? (minute 6.20)</p>

<p>Am I right, saying that signatures for segwit outputs will never be relayed to old clients?</p>

<segregated-witness><transaction-propagation>
Segwit: dropping signature from relay
domegabri
# Segwit: dropping signature from relay

(Asked by: username_0 on 2018-03-06)

In the process of trying to understand the effects of segwit on Bitcoin I started watching this:

<https://www.youtube.com/watch?v=NOYNZB5BCHM>

Which are the cases in which the receiver does not need the signatures? (minute 6.20)

Am I right, saying that signatures for segwit outputs will never be relayed to old clients?

**Tags:** segregated-witness, transaction-propagation


---

## 2 answers

### Answer by username_1 on 2018-03-06. Score: 1 | Accepted answer

Yes and no: this is a presentation from 2015, and you are referencing a section which Pieter described as "assume we can redesign bitcoin". So bitcoin hasn't been redesigned, and not everything has been implemented as described in 6:20.

How it is handled today is part of a discussion [with Andrew in bitcointalk](https://bitcointalk.org/index.php?topic=1682183.msg21389041#msg21389041) (read down to page end). Older nodes don't get to see the witness data. They get just tx data, in an "anyone can spend" way, so it is recognized as valid tx by older nodes. Newer nodes get the witness data (of course).

> Am i right saying that signatures for segwit outputs will never be
> relayed to old clients?

yes.


---

### Answer by username_2 on 2018-03-06. Score: 0

When nodes connect, they introduce themselves to each other by telling each other their service flags. One of these service flags, `NODE_WITNESS`, informs their counterpart whether a node is segwit-capable. Only nodes that set `NODE_WITNESS` will receive the full transaction, other peers will be sent the stripped transaction without the witness data.

Note that `NODE_WITNESS` was [introduced in the 0.13-branch](https://github.com/bitcoin/bitcoin/commit/b8a97498df1e83f8dcc49bc3fa4344f9e9799242) of Bitcoin Core. This means that the last non-segwit version of Bitcoin Core has been End of Life since at least 2018.

> **Comments:**
> **username_3**: If an old peer receives, then rebroadcasts that transaction, won't the rebroadcast transaction be useless since it doesn't have the witness data? Wouldn't it be dropped as invalid by the first segwit node that gets it?  
> **username_2**: @BT: Segwit nodes will never ask non-segwit nodes for transactions.  

---

