While major public blockchains like Bitcoin, Litecoin or Ethereum are well-known to the public, the private ones are not so famous. Here will be reviewed the main private blockchains in the article, as well as highlight the key similarities and differences.
As its name suggests, private blockchains are the complete opposite of public blockchains. In public blockchains, anyone can participate because it is open to everyone and anyone can read, write and audit information within the blockchain, however, that is not the case with private blockchains unless one has permission to do so. In private blockchains the owner is usually a single entity, that is why it is not, in its true sense, decentralized. It is more of a distributed data ledger with embedded cryptographic protection in it. However, that is not a drawback but another concept. The private blockchain is supposed to be faster and cheaper than its public analog because the system does not need to spend high amounts of energy, time and money to reach consensus here. But from another point of view, it is relatively less secure and non-transparent as opposed to public blockchains.
Although the differences above are a good way to identify which blockchain is better suited for a specific use case, there are similarities between both types which can make it confusing to make the right choice:
Photo by William Iven on Unsplash
Here will be reviewed most popular private blockchains and their usage and mining statistics. Most of them are well-known for people in crypto and some of them are released an only month ago, but each of them has its advantages and technical features.
Monero is technically a Bytecoin fork which utilizes the CryptoNote protocol for one of the layers, Ring Signatures for transaction signing, Ring CT for transaction hiding and Stealth Addresses for the purpose of hiding the users’ addresses. Upon creation of an address, a user receives three keys — 1 for review incoming transaction and balance, 1 for sending and 1 public key. 3rd parties can review addresses and transaction only having the review key.
The Monero team is currently developing Kovri Project which will route and encrypt transactions using I2P Invisible Internet Project nodes. This will help to hide transactors’ IP addresses and provide further protection from external monitoring. In addition to the above, Monero is ASIC-resistant proof of work.
Here is the most interesting statistics:
The ZCash blockchain is built based on the Bitcoin blockchain, with zk-SNARK technology embedded, which allows private transactions and hides private address balances. There are two types of addresses in ZCash blockchain — private (starting with “z”) and public (starting with “t”), therefore there are four types of transactions available. “Mixed”, private-to-public transactions are hidden only from the private side. Private addresses may also send encrypted messages within private transactions. The owner of private addresses may also reveal information regarding his transactions to regulators and auditors, however, the addresses of counterparties cannot be revealed.
Here is the most interesting statistics:
DASH is built based on Bitcoin blockchain and it has 2 different types of nodes (on the contrary to is “parent”) — usual nodes and masternodes, which have the ability to privately sending and quick-sending of transactions (around 1 second). DASH uses CoinJoin protocol and utilizes I2P Invisible Internet Project nodes technology for privacy purposes.
Here is the most interesting statistics:
PIVX is based on DASH technology, so the key main features of PIVX are the same, however, PIVX utilizes the PoS protocol of Zerocoin for consensus whereas DASH is PoW. The network speed of PIVX is circa 170 TPS. In addition to the above, PIVX team is globally decentralized with no central ruling company. The project is maintained by the community. The project is also claiming itself to be energy-efficient with an estimate of 1 wind turbine to fully power the network.
Here is the most interesting statistics:
Verge is based on the Bitcoin blockchain with multiple layers for privacy. One of the layers is Tor for hiding IP addresses and the other is I2P, similar to Dash for privacy purposes, as well. Verge has a built-in Wraith protocol which allows the choice between private and public network somewhat similar to ZCash. Verge uses a PoW protocol, however, there are 5 different mining algorithms, each of which takes 30 seconds to execute, which provides protection from 51% of attacks. The verge team also claims to support atomic swaps between blockchains that support BIP65.
Here is the most interesting statistics:
BTCp is a fork-merge of ZClassic and Bitcoin, which allows for 4 different types of transactions. BTCp utilizes ZCash’s zk-SNARK tech to hide transactions. BTCp utilizes a PoW protocol similar to the one of Bitcoin Gold, therefore, having same block time. The team is currently developing the Dandelion protocol, which will improve the security of transactions.
The total supply of BTCp should have been the sum of the total BTC supply at BTCp launch date plus the total supply of ZClassic at the same date plus 62,500 BTCp under Volutary Mining Contribution Program. However, the actual amount of BTCp upon launch was higher that it should have been. You can read more about this vulnerability and understand what could be wrong with this project.
Here is the most interesting statistics:
MimbleWimble is a blockchain format and protocol which provides scalability, fungibility, and privacy. Grin is an open source project which implements MimbleWimble blockchain and provides blockchain environment. Grin has privacy by default and also allows for the partial disclosure of information if need be. The Grin blockchain scale in relation to the number of users and minimally in relation to the number of transactions, because of the check that each new transaction does not have any new coins, previous blocks can be removed without concern.
Based on that, the Grin blockchain takes much less disk space in comparison with competitors. The blockchain itself is simply designed and easy-to-audit and maintain. The Grin blockchain utilized time-proven Elliptic Curves which have been used for decades. The Grin blockchain is developed by the community, utilized ASIC-resistant algorithm (Cuckoo Cycle) while encouraging miner decentralization. It also supports sidechains and Quantum-resistant.
Here is the most interesting statistics:
There is definitely a lot of banks that are interested in private blockchains. In some cases, they are happy with public blockchains as well. The opposition to just doing things on a public blockchain is definitely smaller than some of the strongest detractors think. — Vitalik Buterin
Each of the private blockchains has its own features, mainly related to the privacy of the data and has its own strong and weak sides. However, even though blockchain technology itself is still in its early stage and the whole market is tiny when compared to other markets, private blockchain share is even tinier — even on well-known blockchains focusing on privacy (like ZCash) still have relatively low volumes of transactions when compared to their public rivals. Regardless of that, private blockchains definitely have their customers and market, therefore their development is not in vain.
It is also worth noting that private blockchains implement technical solutions which have proven their relative effectiveness in privacy protection like Tor, I2P, etc. However, there is no such thing as absolute privacy and 100% anonymity, and the attacks against privacy are getting better. One should use common sense, prudence and in-depth cautiousness to keep their privacy safe.