So, there is a kind of centralized authority that decides who has a right to contribute to and to audit the network. What is more – it’s possible to restrict viewing information stored on private blockchains. It might seem that in such conditions, a blockchain is no longer the blockchain as it lacks transparency and decentralization. Well, these remarks are fair, but only when the network is estimated from the outside. Within it, the rules remain the same as for public networks: it is still transparent for all the members.
Cuando esta transacción recibe las suficientes confirmaciones, se manda una notificación a la otra cadena de bloques (la que tú quieres utilizar) en el que se adjunta la prueba de que las monedas han sido enviadas por ti a esa dirección especial de la red. Tras ello, en la sidechain se creará, de forma automática, el mismo número exacto de activos que bitcoins se mandaron, dándote a ti el control de los mismos. Es decir, replica en el nuevo activo la cuantía que has enviado de la cadena principal a la sidechain. ¡Muy importante! Recordar que no se han creado o destruido nuevos bitcoins. Simplemente se han movido hasta que no estén usándose en la sidechain.
A Sidechain, in simplest terms, is just a separate blockchain but is attached to the parent through the use of a two-way peg which allows for assets to be interchangeable and moved across the chain at a fixed deterministic exchange rate. This two-way peg works by utilizing simple payment verification or SPV as it's otherwise known. To show and prove ownership of the assets on the parent chain.
By definition, blockchain is a ledger of all transactions that have been executed and could be seen as a write-only platform, wherein transactions once executed cannot be modified later. This platform has been further divided into Public and Private blockchain. Is there a third one? a hybrid mode such as a ‘Consortium blockchain’ as represented by Vitalik Buterin, founder of Ethereum, a decentralized web 3.0 publishing platform.
Blockstream recently released a whitepaper on “strong federations,” which is essentially their vision of a federated two-way peg system. Liquid is a sidechain created by Blockstream that uses the strong federations model. The sidechain is used to transfer bitcoins between centralized bitcoin institutions, such as exchanges, at a faster pace than the public Bitcoin blockchain.
@gendal, good question. Think of the identity hash as a bitcoin address, it is indeed public. So to assert anything with this identity you need to sign the object you are creating or changing with the identity’s private key. Specifically it is a private key that corresponds to a public key that you published in your identity’s object (json). The signature is not placed on the bitcoin transaction, as OP_RETURN has only 40 bytes. The signature is added to a [json] object that is modified with this identity. If you see any fault with this, please let me know.

– A consensus much faster: the fact that the consensus mechanism is centralized makes it much quicker. In fact, the term “consensus” is no longer adapted since it is rather a recording of transactions on the blockchain. Note that the entity responsible for managing the blockchain can decide to change the parameters of the blockchain and in particular to increase the size of the blocks to be able to add more transactions.
The sole distinction between public and private blockchain is related to who is allowed to participate in the network, execute the consensus protocol and maintain the shared ledger. A public blockchain network is completely open and anyone can join and participate in the network. The network typically has an incentivizing mechanism to encourage more participants to join the network. Bitcoin is one of the largest public blockchain networks in production today.