> Aztec.nr API reference, v6.0.0 (mainnet and testnet). Index: https://docs.aztec.network/aztec-nr-api/v6.0.0/llms.txt

# Trait OwnedStateVariable

Module: `noir_aztec::state_vars`

```rust
pub trait OwnedStateVariable<Context> {
    // Required methods
    pub fn new(context: Context, storage_slot: Field, owner: AztecAddress) -> Self;
}
```

A trait that defines the interface for Aztec state variables that have an owner. Unlike regular state variables, owned state variables need to be wrapped in `Owned` state variable when placed in storage:

```rust
#[storage]
struct Storage {
    balance: Owned<PrivateSet<UintNote, Context>, Context>,
}
```

Owned state variables are only used when working with private data because, in the public context, write permissions are solely defined by the contract logic, and anyone can read data. In private, however, modifying state (nullifying private notes) requires both knowledge of the note (the note commitment preimage) and possession of the corresponding nullifier hiding key.

## So what is an Owner?

An **owner** is generally the entity that:

1. Can decrypt the message in which the given note pertaining to the state variable was sent,
2. has the ability to nullify (spend/destroy) those notes.

(Note that point 1 does not necessarily have to be true; for example, the note message could be encrypted for a decrypting service address, which could then deliver the note to the actual owner via offchain communication.)

## Type Parameters

- `Context` - The execution context type (e.g., `PublicContext`, `PrivateContext`, `UtilityContext`). The context determines which methods of the state variable are available and controls whether the variable can be accessed in public, private or utility functions.

## Required methods

```rust
pub fn new(context: Context, storage_slot: Field, owner: AztecAddress) -> Self
```

Initializes a new owned state variable with a given storage slot and owner. The storage slot is inherited from the `Owned` state variable unchanged. The `Owned` state variable calls this function when its `at` method is invoked.

## Implementors

```rust
impl<Context> OwnedStateVariable<Context> for BalanceSet<Context>
```

```rust
impl<Context, Note> OwnedStateVariable<Context> for PrivateImmutable<Note, Context>
```

```rust
impl<Context, Note> OwnedStateVariable<Context> for PrivateMutable<Note, Context>
```

```rust
impl<Context, Note> OwnedStateVariable<Context> for PrivateSet<Note, Context>
```

```rust
impl<Context> OwnedStateVariable<Context> for SingleUseClaim<Context>
```