<p>Not really. Both use OP_CLTV, in order to recover from a situation where one side refuses to participate in the protocol, but other than that, they're pretty different.</p>

<p><a href="https://bitcoincore.org/en/2016/02/26/zero-knowledge-contingent-payments-announcement/" rel="nofollow">ZKCP</a> has a zero knowledge proof communicated outside of the blockchain. On the other hand, HTLC passes signed transactions back and forth to update a channel.</p>

CC BY-SA 3.0
2016-05-04T17:21:10.740Z
2016-05-04T17:21:10.740Z
Nick ODell
<p>This answer to <a href="https://bitcoin.stackexchange.com/a/43190/5406">How is a node in the middle prohibited from keeping the money in a routed Payment in Lightning network?</a> describes how a Hashed Timelock Contract would be used to exchange the "secret" for a payment. This sounds a lot like the <a href="https://bitcointalk.org/index.php?topic=1378318.0" rel="nofollow noreferrer">Zero-Knowledge Contingent Payment</a> described by Greg Maxwell.</p>

<p>Would I be correct in assuming that the HTLC would be implemented including a ZKCP?</p>

<cryptography><locktime><zero-knowledge>
Are Hashed Timelock Contracts and Zero-Knowledge Contingent Payments the same thing?
Murch
# Are Hashed Timelock Contracts and Zero-Knowledge Contingent Payments the same thing?

(Asked by: username_0 on 2016-05-03)

This answer to [How is a node in the middle prohibited from keeping the money in a routed Payment in Lightning network?](https://bitcoin.stackexchange.com/a/43190/5406) describes how a Hashed Timelock Contract would be used to exchange the "secret" for a payment. This sounds a lot like the [Zero-Knowledge Contingent Payment](https://bitcointalk.org/index.php?topic=1378318.0) described by Greg Maxwell.

Would I be correct in assuming that the HTLC would be implemented including a ZKCP?

**Tags:** cryptography, locktime, zero-knowledge


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## 1 answers

### Answer by username_1 on 2016-05-04. Score: 2 | Accepted answer

Not really. Both use OP\_CLTV, in order to recover from a situation where one side refuses to participate in the protocol, but other than that, they're pretty different.

[ZKCP](https://bitcoincore.org/en/2016/02/26/zero-knowledge-contingent-payments-announcement/) has a zero knowledge proof communicated outside of the blockchain. On the other hand, HTLC passes signed transactions back and forth to update a channel.


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