This section includes some additional concepts that the reader might want to look at to supplement their knowledge:

• Zero-knowledge proof (ZKP): ZKP is a mechanism that gives the user the ability to prove that they possess some specific knowledge or information without sharing the knowledge or information with the verifier or validator. ZKP workflows have been in the spotlight after a string of cybersecurity hacks in which large volumes of customer data were lost. Cybersecurity experts have been looking at ZKP workflows to counter such attacks. The solution that this technology offers is to avoid storing any data with service providers, where it can be leaked. Instead, customers can enable a ZKP workflow to verify details about themselves. Hence, if a customer is required to prove that they are above the age of 18 at a restaurant that serves alcohol, a ZKP workflow would allow them to do so without revealing their date of birth and sharing a copy of the document for proof. From a financial services point of view, it makes sense because banks and financial institutions have, at times, a lot of customer data, which might get leaked. A ZKP workflow would permit these institutions to meet compliance norms without actually storing the data. Additionally, customers would be in control of their data. Blockchains are perfect for implementing such workflows owing to their decentralized nature.

• Sharding: Sharding is a database architecture that focuses on horizontal partitioning. A single table's rows are separated into multiple rows. Each partition has the same table schema but entirely different rows. This enables the developers to write to the database at high speeds. Several blockchain platforms have been playing with the idea of enabling sharding for their platform to achieve higher transaction sizing suitable for use cases such as trading or cross-border payments. The Elastico platform has successfully managed to make sharding work for blockchains. Other popular platforms, such as R3's Corda, are exploring integrating sharding with their core set of features. Given the high frequency of transactions required by many financial products, we might be seeing sharding in blockchain become more common soon.
• Blockchain oracles: A blockchain oracle is a third party that provides off-chain information to a smart contract to enable it to process workflows. For example, if a smart contract is supposed to transfer electricity tokens to a customer when the temperature reaches below 40 °F, you can create an application that uses a sensor to detect the temperature and then calls the smart contract to transfer the tokens. In this case, the application and the sensor is an oracle. Oracles are not a new concept in blockchain. However, with organizations integrating more and more IoT devices with blockchains, it will be especially interesting to see their role in the next age of blockchain applications.
• Multisignature wallets: Multisignature (Multisig) wallets are the blockchain equivalent of a secure deposit box with two locks and two keys. Transactions from the wallet need to be signed by two or more stakeholders. To enable this feature, we use the Multsig concept, which is a digital signature mechanism that makes it possible for two or more users to sign a transaction. Each user has access to a private key that they need to sign with when a transaction is to be submitted from the multisig wallet. Wallets can be 2 out of 2, 2 out of 3, 3 out of 5, and so on. The first number in this representation indicates the minimum number of key holders who need to sign to initiate successful transactions. The second number indicates the total number of keys issued for the address. These have been popular with cryptocurrency exchanges for quite some time now. With blockchains now issuing digital assets mapped to real-world assets, organizations might want to remove a single point of failure while storing assets by using Multisig wallets. 

• Stablecoins: Stablecoins are crypto assets issued on blockchains that are pegged to a single currency or a basket of currency. This reduces volatility in their prices and makes them suitable for financial applications such as cross-border remittances. Several reputed organizations such as JP Morgan have been experimenting with building their own stablecoins for settlement instead of fiat.
• Sidechains: Sidechain is an approach by means of which tokens and assets in one blockchain can be moved across multiple blockchains or ledgers. Probably the best way to think about sidechains is like a ledger on top of our blockchain ledger. They have multiple uses in the real world. Consider the bitcoin network. Currently, transactions are processed at a very slow rate. We could run a ledger parallel to the bitcoin network that works on a different consensus mechanism and processes transactions much faster than Bitcoin. To do so, we can invite individuals interested in faster payments to sign up for our application and ask them to load bitcoins in their wallets on the alternate ledger. To load bitcoins into their wallet, they would transfer bitcoins to a designated address on the bitcoin network. After receiving the bitcoins in the designated address, the customer is credited with the balance on the parallel ledger. On the parallel ledger, they can transfer funds much faster than the bitcoin network. If they want to withdraw, we'll simply debit the designated address and credit the customer's address on the bitcoin network. This concept is called a sidechain, and the parallel ledger is referred to as a sidechain ledger. It is used for increasing transaction speeds, hopping between different DLT networks, lowering transaction costs, interoperability between networks, and so on.