Covenant By Example

Learn Covenant
through annotated code.

15 chapters. From hello contract to encrypted tokens, post-quantum signatures, and full deployment — with real code at every step.

15chapters
3sections
Apache-2.0open source
V0.7 GAcompiler

Fundamentals

Chapters 1–5 — Records, fields, actions, guards, and external calls — the language core.
Chapter 1Hello ContractThe simplest Covenant contract — record, action, view.Chapter 2Fields and StorageEvery primitive type, plus arrays and maps.Chapter 3Actions, Events & Errorsemit, transfer, revert_with — the full action vocabulary.Chapter 4Guardsonly, when, given — declarative access control and invariants.Chapter 5External Contract Callsinterface, @non_reentrant, and the CEI pattern.

Standards

Chapters 6–10 — ERC-20, FHE, encrypted tokens, post-quantum signatures, and ZK proofs.
Chapter 6ERC-20 TokenSix lines versus one hundred — the token keyword.Chapter 7FHE Basicsencrypted<T>, fhe_add, fhe_mul — computing on encrypted state.Chapter 8Encrypted Token (ERC-8227)Private balances with selective disclosure.Chapter 9Post-Quantum Signaturespq_key, @pq_signed — Dilithium-5 authentication.Chapter 10Zero-Knowledge Proofsselective_disclosure, verified_by — proving properties without revealing data.

Advanced

Chapters 11–15 — Cryptographic amnesia, UUPS upgrades, beacon proxies, oracles, and deployment.
Chapter 11Cryptographic Amnesia (ERC-8228)amnesia<T>, destroy(), vdf_proof — verifiable data deletion.Chapter 12UUPS Upgradeableupgradeable_by, version, migrate — safe contract upgrades.Chapter 13Beacon Proxy Pattern@proxy_compatible, deploy_proxy — upgrading many instances atomically.Chapter 14Oracle IntegrationChainlink price feeds — staleness checks and typed errors.Chapter 15Deploy to SepoliaInstall, compile, deploy, verify — end-to-end in four commands.