Goguen Phase

The Goguen phase is one of five named eras in the development roadmap of Cardano (ADA), the proof-of-stake blockchain. Its purpose was to turn Cardano from a network that could only transfer its own coin into a platform for tokens and smart contracts. The key milestones were the Mary upgrade of March 2021, which introduced native tokens, and the Alonzo upgrade of September 2021, which enabled smart contracts written with the Plutus platform.

Cardano's roadmap divides its work into Byron (foundation), Shelley (decentralization), Goguen (smart contracts), Basho (scaling) and Voltaire (governance), each named after a historical figure. Goguen honours Joseph Goguen, an American computer scientist known for work on programming language theory and formal methods. The eras overlap rather than following one another strictly, and much of the work was carried out by Input Output, the engineering company described under Input-Output Hong Kong (IOHK).

Imagine a new city whose first roads and power lines have just been finished. People can move around and pay each other, but there are no shops, offices or services yet. The Goguen phase was the period in which Cardano's builders added the rules and tools that let others set up those shops and services.

In practice, that meant two things. First, anyone could create their own coins or tokens on Cardano. Second, developers could write programs that run automatically on the blockchain, such as exchanges, lending services or games. Before Goguen, Cardano could do little more than move its own currency from one person to another.

Cardano introduces changes through planned upgrades handled by its Hard Fork Combinator, which lets new rules take effect without restarting the chain. The upgrades usually linked to Goguen were:

• Allegra, December 2020. Added the ability to lock tokens until a set time, an early building block for more complex contracts.
• Mary, March 2021. Introduced native tokens, which can be created and moved on the main ledger without a smart contract, unlike many tokens on Ethereum that rely on contract code.
• Alonzo, September 2021. Activated Plutus smart contracts on the main network on 12 September 2021, making decentralized applications possible.

Later upgrades improved smart-contract performance and costs, which developers had criticized in the months after Alonzo.

Plutus, Cardano's smart-contract platform, is based on the Haskell programming language, which reflects the project's emphasis on formal methods and mathematically checkable code. Cardano also offered Marlowe, a simpler language aimed at financial contracts. Cardano uses an extended version of the unspent transaction output (UTXO) model that Bitcoin uses, rather than the account model of Ethereum. This makes the outcome of a transaction easier to predict before it is submitted, but early on it made it harder to build applications in which many users interact with the same contract at once, a challenge known as concurrency that early decentralized exchanges on Cardano had to work around.

Because native tokens on Cardano are handled by the ledger itself, sending them follows the same rules as sending ADA and does not need custom contract code. Supporters argue this makes tokens cheaper and safer to move, since there is no contract to contain bugs. Tokens are created under "minting policies" that set who may issue or destroy them. The same mechanism is used for non-fungible tokens, which became a significant part of Cardano activity after the Mary upgrade.

The Goguen work gave Cardano the basic features expected of a smart-contract platform, and an ecosystem of decentralized exchanges, lending protocols, stablecoins and NFT projects followed. Critics noted that smart contracts arrived years after Ethereum and several rival networks, and that early performance limits slowed adoption. Measures of activity, such as total value locked, have remained smaller than on Ethereum. Cardano's later phases continued the roadmap: Basho focused on scaling, including the Hydra protocol, and Voltaire on on-chain governance, where holders of ADA and elected representatives vote on changes. Projects building during Goguen often raised funds through initial stake pool offerings, a model specific to Cardano's staking design, and many relied on Cardano's proof of stake rewards to attract users. A broader view of how the network fits together is given under Byron phase, the first era.

• Cardano roadmap