[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › local‑first/Owner Owner identity and cryptographic key derivation. ## Functions | Function | Description | | --------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [createAppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createAppOwner) | Creates an [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) from an [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret). | | [createOwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createOwnerSecret) | Creates a [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret). | | [createOwnerWebSocketTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createOwnerWebSocketTransport) | Creates an [OwnerWebSocketTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/OwnerWebSocketTransport) for the given relay URL and [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId). | | [createOwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createOwnerWriteKey) | Creates a new random [OwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerWriteKey) for rotation. | | [createShardOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createShardOwner) | Creates a [ShardOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/ShardOwner) from an [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret). | | [createSharedOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createSharedOwner) | Creates a [SharedOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedOwner) from an [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) for collaborative write access. | | [createSharedReadonlyOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createSharedReadonlyOwner) | Creates a [SharedReadonlyOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedReadonlyOwner) from a [SharedOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedOwner). | | [deriveShardOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/deriveShardOwner) | Derives a [ShardOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/ShardOwner) from an [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) using the specified path. | | [mnemonicToOwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/mnemonicToOwnerSecret) | Converts a [Mnemonic](https://evolu.dev/docs/api-reference/common/Type/variables/Mnemonic) to an [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret). | | [ownerIdBytesToOwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/ownerIdBytesToOwnerId) | Converts [OwnerIdBytes](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerIdBytes) to [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId). | | [ownerIdToOwnerIdBytes](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/ownerIdToOwnerIdBytes) | Converts [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId) to [OwnerIdBytes](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerIdBytes). | | [ownerSecretToMnemonic](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/ownerSecretToMnemonic) | Converts an [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) to a [Mnemonic](https://evolu.dev/docs/api-reference/common/Type/variables/Mnemonic). | | [parseOwnerIdFromOwnerWebSocketTransportUrl](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/parseOwnerIdFromOwnerWebSocketTransportUrl) | Extracts [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId) from an [OwnerWebSocketTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/OwnerWebSocketTransport) URL query string. | ## Interfaces | Interface | Description | | -------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) | The AppOwner represents the application owner. It's created using a cryptographically secure random generator or derived from an external source, e.g., mnemonic stored securely in a hardware device. | | [DeviceAppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/DeviceAppOwner) | An [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) for encrypting device-only data. | | [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) | The Owner represents ownership of data in Evolu. Every database change is assigned to an owner and encrypted with its [OwnerEncryptionKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerEncryptionKey). Owners allow partial sync, only the [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) is synced by default. | | [OwnerError](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/OwnerError) | Common interface implemented by all owner domain errors. | | [OwnerUsage](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/OwnerUsage) | Usage data for an [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId). | | [OwnerWebSocketTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/OwnerWebSocketTransport) | WebSocket transport configuration. | | [ReadonlyOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/ReadonlyOwner) | [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) without a [OwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerWriteKey). | | [ShardOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/ShardOwner) | An [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) for sharding data. | | [SharedOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedOwner) | An [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) for collaborative data with write access. | | [SharedReadonlyOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedReadonlyOwner) | Read-only version of a [SharedOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SharedOwner) for data sharing. Contains only the [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId) and [EncryptionKey](https://evolu.dev/docs/api-reference/common/Crypto/variables/EncryptionKey) needed for others to read the shared data without write access. | | [SyncOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/SyncOwner) | An [ReadonlyOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/ReadonlyOwner) or [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) with non-empty [OwnerTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerTransport)s so it can be synced. | ## Type Aliases | Type Alias | Description | | ------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [OwnerEncryptionKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerEncryptionKey) | Symmetric encryption key for [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) data protection. | | [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerId) | OwnerId is a branded [Id](https://evolu.dev/docs/api-reference/common/Type/variables/Id) that uniquely identifies an [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner). | | [OwnerIdBytes](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerIdBytes) | Bytes representation of [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId). | | [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerSecret) | 32 bytes of cryptographic entropy used to derive [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) keys. | | [OwnerTransport](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerTransport) | Transport configuration for connecting to relays. | | [OwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/type-aliases/OwnerWriteKey) | A secure token for write operations. It's derived from [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) by default and can be rotated via [createOwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createOwnerWriteKey). | ## Variables | Variable | Description | | ----------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [OwnerEncryptionKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerEncryptionKey) | Symmetric encryption key for [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) data protection. | | [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId) | OwnerId is a branded [Id](https://evolu.dev/docs/api-reference/common/Type/variables/Id) that uniquely identifies an [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner). | | [OwnerIdBytes](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerIdBytes) | Bytes representation of [OwnerId](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerId). | | [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) | 32 bytes of cryptographic entropy used to derive [Owner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/Owner) keys. | | [OwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerWriteKey) | A secure token for write operations. It's derived from [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) by default and can be rotated via [createOwnerWriteKey](https://evolu.dev/docs/api-reference/common/local-first/Owner/functions/createOwnerWriteKey). | | [ownerWriteKeyLength](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/ownerWriteKeyLength) | - | | [testAppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/testAppOwner) | Deterministic [AppOwner](https://evolu.dev/docs/api-reference/common/local-first/Owner/interfaces/AppOwner) for tests. | | [testOwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/testOwnerSecret) | Deterministic [OwnerSecret](https://evolu.dev/docs/api-reference/common/local-first/Owner/variables/OwnerSecret) for tests. |