Encrypted Maps (vetKeys)

EncryptedMaps is a ready-made vetKeys library for access-controlled, end-to-end encrypted key-value storage. Each map is owned by a principal and holds mapKey → value entries; values are encrypted on the client under a vetKey and the canister only ever stores ciphertext. Owners share maps with other principals at three access levels. This is the default starting point for any encrypted-storage app (password manager, encrypted notes, vault).

Use the vetkeys skill instead when you need lower-level primitives: identity-based encryption (IBE), threshold BLS signatures, timelock encryption, or your own symmetric-key scheme.

Use @icp-sdk/vetkeys (≥0.5), not the legacy @dfinity/vetkeys (frozen at 0.4). Frontend agent/identity come from @icp-sdk/core, not @dfinity/agent.

Concepts

• Map — identified by (mapOwner: Principal, mapName: bytes). Contains mapKey → encryptedValue entries. mapName and mapKey are byte arrays, max 32 bytes each.
• Access rights — Read, ReadWrite, ReadWriteManage (manage = may grant/revoke others). The owner always has full rights.
• Client-side encryption — the frontend fetches a per-map vetKey and encrypts/decrypts locally; the canister enforces access control and stores ciphertext. Sharing a map re-encrypts the map key for the new user automatically.
• Key name & domain separator are immutable once any value is encrypted — they feed key derivation, so changing them makes stored values undecryptable. See pitfalls.