what is the motivation behind sidechain?

Question

I learnt from another SE post that sidechaining is any mechanism that allows tokens from one blockchain to be securely used within a completely separate blockchain but still moved back to the original chain if necessary I want to know what is the motivation behind this idea why one would do that and are there any resources available for implementing sidechaining on your local machine for experimentation.

Answer 1

Source : https://gendal.me/2014/10/26/a-simple-explanation-of-bitcoin-sidechains/

Here’s the Sidechains insight

The key idea behind the sidechains concept is:

What if you could send Bitcoins not only to individuals, addresses, and centralized services but to other blockchains?

Imagine there is a Bitcoin-like system out there that you’d like to use. Perhaps it’s litecoin or ethereum or perhaps it’s something brand new. Maybe it has a faster block confirmation interval and a richer scripting language. It doesn’t matter. The point is: you’d like to use it but would rather not have to go through the risk and effort of buying the native tokens for that platform. You have Bitcoins already. Why can’t you use them?

The sidechains ideas are this:

• Send your Bitcoins to a specially formed Bitcoin address. The address is specially designed so that the coins will now be out of your control… and out of the control of anybody else either. They’re completely immobilized and can only be unlocked if somebody can prove they’re no longer being used elsewhere (I’ll explain what I mean by this in a minute). In other words, you’ve used the core bitcoin transaction rules I described above to lay down a specific condition that the future owner – whoever it ends up being – needs to fulfill in order to take control

• Once this immobilization transaction is sufficiently confirmed, you send a message to the other blockchain – the one you were wanting to use. This message contains a proof that the coins were sent to that special address on the Bitcoin network, that they are therefore now immobilized and, crucially, that you were the one who did it

• If the second blockchain has agreed to be a Bitcoin sidechain, it now does something really special… it creates the exact same number of tokens on its own network and gives you control of them.

• So it’s as if your Bitcoins have been transferred to this second chain. And remember: they’re immobilized on the Bitcoin network… so we haven’t created or destroyed any…. Just “moved” them.

• You can now transact with those coins on that second chain, under whatever rules that chain chooses to implement.

• Perhaps blocks are created faster on that sidechain. Perhaps transaction scripts are “Turing complete”. Perhaps you have to pay fees to incent those securing that sidechain. Who knows. The rules can be whatever those running that sidechain want them to be. The the only rule that matters is that the sidechain agrees to follow the convention that if you can prove you put some Bitcoins out of reach on the Bitcoin network, the same number will pop into existence on the sidechain.

• And now for the second clever part. The logic above is symmetric. So, at any point, whoever is holding these coins on the sidechain can send them back to the Bitcoin network by creating a special transaction on the sidechain that immobilizes the bitcoins on the sidechain. They’ll disappear from the sidechain and become available again on the Bitcoin network, under the control of whoever last owned them on the sidechain.

Sidechains use the standard bitcoin “three-step” transaction to immobilize bitcoins whilst they’re “on” the sidechain

So, to repeat, we’ve used standard Bitcoin transaction functionality to move coins out of reach and we then prove to a second, unrelated chain, that we’ve done this. And when we’re done, whoever owns them on the sidechain can do the same thing and send them back to the bitcoin network.

So developers get the opportunity to experiment with different types of cryptocurrency rules without needing to create their own currency.