<p>The seminal whitepaper on sidechains, &quot;<a href="https://blockstream.com/sidechains.pdf" rel="nofollow noreferrer">Enabling Blockchain Innovations with Pegged Sidechains</a>,&quot; describes modifying Bitcoin's Script to support simplified payment validation (SPV):</p>
<blockquote>
<p>To use Bitcoin as the parent chain, an extension to script which can recognise and validate such SPV proofs would be required. At the very least, such proofs would need to be made compact enough to fit in a Bitcoin transaction. However, this is just a soft-forking change⁹, without effect on transactions which do not use the new features.</p>
<p><sup>⁹A soft-forking change is a change which only imposes further restrictions on what is valid inside the chain.</sup></p>
</blockquote>
<p>However, this is for a &quot;two-way peg.&quot;</p>
<p>For a so-called &quot;federated peg,&quot; which does not require a modification to Bitcoin, see Appendix A of <a href="https://blockstream.com/sidechains.pdf" rel="nofollow noreferrer">the whitepaper</a> or circa 15 min. into <a href="https://blockstream.com/developers/" rel="nofollow noreferrer">Greg Maxwell's presentation</a>.</p>

CC BY-SA 3.0
2016-01-29T17:22:05.290Z
Sorry but I didn't get it. Does bitcoin support sidechain at the moment or not? How did Blockstream do it if it does not support?
Peter Mel
CC BY-SA 3.0
2016-01-29T17:23:56.970Z
@PeterMel No, it would require a modification to Bitcoin's Script.
Geremia
CC BY-SA 3.0
2016-01-29T17:25:20.793Z
So how did they launch Liquid !!!???
Peter Mel
CC BY-SA 3.0
2016-01-29T19:13:11.413Z
@PeterMel I think they mean they launched the project, not that it's been implemented in the actual Bitcoin network.
Geremia
CC BY-SA 3.0
2016-01-29T19:18:38.527Z
@PeterMel Have you seen [Greg Maxwell's informative video](https://blockstream.com/developers/)?
Geremia
CC BY-SA 3.0
2016-01-29T20:22:40.087Z
@PeterMel Also, see my edit regarding "federated pegs."
Geremia
CC BY-SA 3.0
2016-01-29T16:49:02.517Z
2016-01-29T20:22:21.470Z
2020-06-16T11:10:03.350Z
Geremia
<p>I've been reading about Blockstream and <a href="https://blockstream.com/2015/10/12/introducing-liquid/" rel="nofollow">Liquid</a> but I was under the impression that sidechain was something that would require changes to the Bitcoin Core platform. Is that correct? I mean, is the bicoin blockchain already supporting a "peg" to another sidechain? Can I already launch my own sidechain like Blockstream did?</p>

<sidechains><blockstream>
I want to launch my own simple sidechain pegged to bitcoin for testing purposes. Can it be done?
Peter Mel
# I want to launch my own simple sidechain pegged to bitcoin for testing purposes. Can it be done?

(Asked by: username_0 on 2016-01-28)

I've been reading about Blockstream and [Liquid](https://blockstream.com/2015/10/12/introducing-liquid/) but I was under the impression that sidechain was something that would require changes to the Bitcoin Core platform. Is that correct? I mean, is the bicoin blockchain already supporting a "peg" to another sidechain? Can I already launch my own sidechain like Blockstream did?

**Tags:** sidechains, blockstream


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## 1 answers

### Answer by username_1 on 2016-01-29. Score: 2 | Accepted answer

The seminal whitepaper on sidechains, "[Enabling Blockchain Innovations with Pegged Sidechains](https://blockstream.com/sidechains.pdf)," describes modifying Bitcoin's Script to support simplified payment validation (SPV):

> To use Bitcoin as the parent chain, an extension to script which can recognise and validate such SPV proofs would be required. At the very least, such proofs would need to be made compact enough to fit in a Bitcoin transaction. However, this is just a soft-forking change⁹, without effect on transactions which do not use the new features.
>
> ⁹A soft-forking change is a change which only imposes further restrictions on what is valid inside the chain.

However, this is for a "two-way peg."

For a so-called "federated peg," which does not require a modification to Bitcoin, see Appendix A of [the whitepaper](https://blockstream.com/sidechains.pdf) or circa 15 min. into [Greg Maxwell's presentation](https://blockstream.com/developers/).

> **Comments:**
> **username_0**: Sorry but I didn't get it. Does bitcoin support sidechain at the moment or not? How did Blockstream do it if it does not support?  
> **username_1**: @username_0 No, it would require a modification to Bitcoin's Script.  
> **username_0**: So how did they launch Liquid !!!???  
> **username_1**: @username_0 I think they mean they launched the project, not that it's been implemented in the actual Bitcoin network.  
> **username_1**: @username_0 Have you seen [Greg Maxwell's informative video](https://blockstream.com/developers/)?  
> **username_1**: @username_0 Also, see my edit regarding "federated pegs."  

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