<p>Pruned peers do not have the full blockchain history and therefore have only limited value for SPV clients.</p>
<p>With Bitcoin Core 0.16, pruned peers will announce their service via <code>NODE_NETWORK_LIMITED</code> (see <a href="https://github.com/bitcoin/bips/blob/master/bip-0159.mediawiki" rel="nofollow noreferrer">BIP159</a>). BIP159 is not a consensus change.</p>
<p>This will allow SPV clients to connect to pruned peers. But, since they only signal for the last 288 blocks, SPV/BIP37 clients interested to load history older than 1 day of blocks would still require to connect to traditional peers.</p>
<p>In the future, pruned nodes may have a way to signal how many blocks they will keep on disk (without adding a fingerprinting vulnerability).</p>
<p>Note that BIP37 is a controversial concept. It has significant privacy downsides (see Jonas Nick's research).</p>
<p>A far better concept is &quot;Client side filtering&quot;. See the upcoming <a href="https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki" rel="nofollow noreferrer">BIP157</a> and <a href="https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki" rel="nofollow noreferrer">BIP158</a>.</p>

CC BY-SA 4.0
2018-01-18T02:35:33.590Z
2021-01-21T14:32:31.360Z
2021-01-21T14:32:31.360Z
Jonas Schnelli
<p>According to Jameson Lopp (<a href="https://www.coindesk.com/spv-support-billion-bitcoin-users-sizing-scaling-claim/" rel="nofollow noreferrer">https://www.coindesk.com/spv-support-billion-bitcoin-users-sizing-scaling-claim/</a>), allowing pruned nodes to advertise that they support BIP 37 would be impossible without "extensive protocol changes." What changes would make this possible? </p>

<spv><pruning><bip37-bloom-filter><node-services>
How could the Bitcoin protocol be modified so that pruned nodes could still participate in BIP 37 SPV?
Ian MathWiz
# How could the Bitcoin protocol be modified so that pruned nodes could still participate in BIP 37 SPV?

(Asked by: username_0 on 2018-01-17)

According to Jameson Lopp (<https://www.coindesk.com/spv-support-billion-bitcoin-users-sizing-scaling-claim/>), allowing pruned nodes to advertise that they support BIP 37 would be impossible without "extensive protocol changes." What changes would make this possible?

**Tags:** spv, pruning, bip37-bloom-filter, node-services


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## 1 answers

### Answer by username_1 on 2018-01-18. Score: 3

Pruned peers do not have the full blockchain history and therefore have only limited value for SPV clients.

With Bitcoin Core 0.16, pruned peers will announce their service via `NODE_NETWORK_LIMITED` (see [BIP159](https://github.com/bitcoin/bips/blob/master/bip-0159.mediawiki)). BIP159 is not a consensus change.

This will allow SPV clients to connect to pruned peers. But, since they only signal for the last 288 blocks, SPV/BIP37 clients interested to load history older than 1 day of blocks would still require to connect to traditional peers.

In the future, pruned nodes may have a way to signal how many blocks they will keep on disk (without adding a fingerprinting vulnerability).

Note that BIP37 is a controversial concept. It has significant privacy downsides (see Jonas Nick's research).

A far better concept is "Client side filtering". See the upcoming [BIP157](https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki) and [BIP158](https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki).


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