The original blockchain created by Bitcoin has inspired thousands of other attempts to record information in the distinctive fashion the cryptocurrency pioneered.

While there’s a hot debate about how to define a blockchain, most projects using the term try to create a single database that is shared and maintained by a group of people or institutions.

The vast majority of blockchains involve new virtual currencies like Bitcoin. But corporations and governments around the world have also become interested in ways to use the technology to reliably store vast amounts of data.

Here are some of the most ambitious blockchain projects companies and governments are working on.

Public Blockchains

Many new cryptocurrencies are like Bitcoin and record all transactions on public blockchains that anyone with a computer can help to update, without requiring permission from anyone.

Public blockchains Blockchain-inspired cryptocurrencies Private blockchains Derived from the same blockchain Other relationship Bitcoin $105 MARKET CAP BIL. The original blockchain-based virtual currency has not lived up to its original goal of being a new online currency, but it has won favor as a scarce digital commodity similar to gold, giving rise to a vast global trading market. All Exonum transactions are anchored on the Bitcoin blockchain. Exonum Built by a large manufacturer of Bitcoin mining computers, Bitfury, Exonum has been marketed to public officials as a way to store government records. Public blockchains Derived from the same blockchain Blockchain-inspired cryptocurrencies Other relationship Private blockchains $105 Bitcoin MARKET CAP BIL. The original blockchain-based virtual currency has not lived up to its original goal of being a new online currency, but it has won favor as a scarce digital commodity similar to gold, giving rise to a vast global trading market. All Exonum transactions are anchored on the Bitcoin blockchain. Exonum Built by a large manufacturer of Bitcoin mining computers, Bitfury, Exonum has been marketed to public officials as a way to store government records.

Ethereum $45 MARKET CAP BIL. Ethereum goes beyond Bitcoin to allow people to write so-called smart contracts into its blockchain, with the goal of creating a shared global computing system. The internal currency, Ether, can be used to pay for computing power. Several private blockchains have taken their basic design from the Ethereum software. Axcore The start-up Axoni has built its own version of Ethereum specifically designed for the financial industry. Autonity The British start-up Clearmatics has worked with several banks to build a so-called Utility Settlement Coin that banks can use to settle transactions between them. Ethereum private blockchain The Enterprise Ethereum Alliance has helped create several private versions of Ethereum and supported companies building applications on top of them. Quorum This closed variant of Ethereum was originally produced by a team at JPMorgan Chase, but has since gained use outside the financial industry. $45 Ethereum MARKET CAP BIL. Ethereum goes beyond Bitcoin to allow people to write so-called smart contracts into its blockchain, with the goal of creating a shared global computing system. The internal currency, Ether, can be used to pay for computing power. Several private blockchains have taken their basic design from the Ethereum software. Axcore The start-up Axoni has built its own version of Ethereum specifically designed for the financial industry. Autonity The British start-up Clearmatics has worked with several banks to build a so-called Utility Settlement Coin that banks can use to settle transactions between them. Ethereum private blockchain The Enterprise Ethereum Alliance has helped create several private versions of Ethereum and supported companies building applications on top of them. Quorum This closed variant of Ethereum was originally produced by a team at JPMorgan Chase, but has since gained use outside the financial industry.

Blockchain-Inspired Cryptocurrencies

A handful of large cryptocurrencies are recorded on ledgers that anyone can access, but that still rely to some degree on a central institution or company. The ledgers for these coins were inspired by blockchains but rely on new data structures.

Ripple $18 MARKET CAP BIL. Ripple is the chief player behind a new kind of shared ledger, which uses the digital token known as XRP. Ripple holds most of the XRP tokens and has encouraged financial firms to use XRP to make cross-border payments faster and cheaper. The Inter Ledger Protocol was created by programmers at Ripple. Inter Ledger Protocol Ripple, the company, developed software that can communicate among different ledgers, even traditional bank ledgers, without digital tokens involved. Stellar was founded by a Ripple co-founder, Jed McCaleb, using Ripple’s code. Stellar $3 MARKET CAP BIL. Jed McCaleb created Stellar after his contentious departure from Ripple. Stellar was McCaleb’s effort to improve on Ripple while using similar principles. It is overseen by a central foundation, and its token is known as the Lumen. I.B.M. has brought Stellar in as a payment method for projects on Fabric. Hyperledger Fabric Hyperledger is a foundation that was spearheaded by IBM and is now run by the Linux Foundation to create global blockchain standards. Fabric is its most successful creation. $18 Ripple MARKET CAP BIL. Ripple is the chief player behind a new kind of shared ledger, which uses the digital token known as XRP. Ripple holds most of the XRP tokens, and has encouraged financial firms to use XRP to make cross-border payments faster and cheaper. The Inter Ledger Protocol was created by programmers at Ripple. Inter Ledger Protocol Ripple, the company, developed software that can communicate among different ledgers, even traditional bank ledgers, without digital tokens involved. Stellar was founded by a Ripple co-founder, Jed McCaleb, using Ripple’s code. $3 Stellar MARKET CAP BIL. Jed McCaleb created Stellar after his contentious departure from Ripple. Stellar was McCaleb’s effort to improve on Ripple while using similar principles. It is overseen by a central foundation, and its token is known as the Lumen. I.B.M. has brought Stellar in as a payment method for projects on Fabric. Hyperledger Fabric Hyperledger is a foundation that was spearheaded by IBM and is now run by the Linux Foundation to create global blockchain standards. Fabric is its most successful creation.

Other Private Blockchains

A number of companies have built their own private blockchains for corporate and government use from the ground up, without using an existing blockchain as a starting point. These private blockchains are designed to be shared among groups of computers, but are not open to the public.