<p>Rootstock uses smart bitcoins (SBTC). On a technical level this is a separate token from bitcoin (BTC). They live on a separate blockchain. On the other hand, every smart bitcoin represents one bitcoin.</p>

<p>Rootstock is a Bitcoin sidechain.</p>

<p>This works as a 2-way peg between the bitcoin blockchain and the rootstock blockchain. You use this to transfer coins between the chains. Send a bitcoin over to rootstock and it becomes a smart bitcoin. Send it back and you have a (normal) bitcoin again.</p>

<p>A more technical way to see it is that X amount of smart bitcoins are created by locking the same amount of bitcoins on the bitcoin blockchain. When you later unlock an amount of bitcoins, the same amount of smart bitcoins disappear again from the roostock blockchain.</p>

<p>The important part is that your bitcoin can only be active on one of the blockchains at any given time.</p>

CC BY-SA 3.0
2017-06-01T14:56:23.090Z
I'm assuming it is a custodial wallet? And if its not, how does it work?
Patoshi パトシ
CC BY-SA 3.0
2017-06-01T15:23:45.883Z
No, you can run your own Rootstock node/wallet if you want. You can download the software from https://github.com/RSKSmart and use that.
Dr.Haribo
CC BY-SA 3.0
2017-06-02T12:51:33.593Z
when you convert your btc. someone had to hold them to give you sbtc. who is this someone?
Patoshi パトシ
CC BY-SA 3.0
2017-06-03T17:34:25.723Z
They are locked, not held by a person. For details see for instance this: http://www.the-blockchain.com/docs/Drivechains%20sidechains%20and%20hybrid%202-way%20peg%20designs%20-%20Sergio%20Lerner%20-%202016.pdf
Dr.Haribo
CC BY-SA 3.0
2017-06-01T14:49:08.560Z
2017-06-01T14:49:08.560Z
Dr.Haribo
<p>Learning about rootstock. Do they ues bitcoin or their own rootstock coin? In ethereum, they have ether, but to execute contracts it requires <em>gas</em>. Is there an equivalent here in rootstock or all of this is in BTC? What would be the fees then?</p>

<transaction-fees><rootstock>
Does rootstock use bitcoins or do they use their own rootstock coin?
Patoshi パトシ
# Does rootstock use bitcoins or do they use their own rootstock coin?

(Asked by: username_0 on 2017-06-01)

Learning about rootstock. Do they ues bitcoin or their own rootstock coin? In ethereum, they have ether, but to execute contracts it requires *gas*. Is there an equivalent here in rootstock or all of this is in BTC? What would be the fees then?

**Tags:** transaction-fees, rootstock


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## 1 answers

### Answer by username_1 on 2017-06-01. Score: 2 | Accepted answer

Rootstock uses smart bitcoins (SBTC). On a technical level this is a separate token from bitcoin (BTC). They live on a separate blockchain. On the other hand, every smart bitcoin represents one bitcoin.

Rootstock is a Bitcoin sidechain.

This works as a 2-way peg between the bitcoin blockchain and the rootstock blockchain. You use this to transfer coins between the chains. Send a bitcoin over to rootstock and it becomes a smart bitcoin. Send it back and you have a (normal) bitcoin again.

A more technical way to see it is that X amount of smart bitcoins are created by locking the same amount of bitcoins on the bitcoin blockchain. When you later unlock an amount of bitcoins, the same amount of smart bitcoins disappear again from the roostock blockchain.

The important part is that your bitcoin can only be active on one of the blockchains at any given time.

> **Comments:**
> **username_0**: I'm assuming it is a custodial wallet? And if its not, how does it work?  
> **username_1**: No, you can run your own Rootstock node/wallet if you want. You can download the software from https://github.com/RSKSmart and use that.  
> **username_0**: when you convert your btc. someone had to hold them to give you sbtc. who is this someone?  
> **username_1**: They are locked, not held by a person. For details see for instance this: http://www.the-blockchain.com/docs/Drivechains%20sidechains%20and%20hybrid%202-way%20peg%20designs%20-%20Sergio%20Lerner%20-%202016.pdf  

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