Table A2: Blockchain Types

The network is open. Any node can join the network, read its contents, write hashes and audit the activities.

Disclosure of identity is not required to join the network (pseudonyms can be used).

The node can do consensus on the blockchain. Consensus involves validating transactions and adding blocks to the blockchain.

Authorized nodes can participate in the network after their identity is verified.

Participants (nodes) must be approved or authorized by a company (the administrator) to join the network.

There are restrictions on who can access the network. Once approved, the user can participate in the network.

Disclosure of identity is required to join the network.

Participants’ identities are known to each other.

Participants’ identities are known to each other.

Any node in the network can validate transactions.

The administrator is the only party to write rules, make decisions or revert transactions on the system. The consensus, then, is centralized.

Blockchain contents are visible to everyone.

Blockchain contents are visible to participants.

Content visibility is defined and restricted by the administrator.

The participant’s role is based on who can write rules, make system changes or participate in validating transactions. Functions are defined and restricted.

The administrator decides which content is visible and accessible to participants.

For example, bitcoin and Ethereum (cryptocurrencies).

For example, Ripple,* a digital global payment system.

For example, central bank digital currencies.

For example, Holochain,** an open-source framework that supports participant autonomy over what they share and with whom they share it.

Sources: Buterin (2015); Yermack (2017); Banerjee (2021); www.gsbn.trade/our-platform.

A group of organizations that share the consortium’s common goals is invited to join and participate in the network.

Participants’ identities are known to each other.

The group validates transactions and creates rules.

Activities are visible only to those who are part of the consortium.

For example, the Global Business Shipping Network, consisting of major shipping lines and global terminal operators from the supply chain who collaborate on cargo release and trade finance.

Notes: *Ripple is a cryptocurrency and blockchain solution provider (https://ripple.com/). **Some of the projects that are using Holochain’s framework are featured on the blockchain’s website (www.holochain.org/projects/). This table segments blockchain technology into four different types based on the level of accessibility and participation they permit and provides examples of each system. These segments are public, private and consortium blockchains. The table further specifies the key features of blockchain based on whether they are permissioned or permissionless. Permissioned blockchains impose restrictions on access and usage of their system. Permissionless blockchain does not have these restrictions. A public blockchain allows any participant to join and participate in the network’s operation. This contrasts with private blockchains. In private blockchains, one organization controls access to and participation in the network. Private blockchain also places restrictions on the type of content accessible to participants. A consortium blockchain has features of both public and private blockchains. One of its key features is that a group of organizations with common goals makes decisions on what terms the network operates (Banerjee 2021).