> For the complete documentation index, see [llms.txt](/llms.txt).

# Ed25519 Private Key

The `getEd25519PrivateKey` method returns the user's Ed25519 private key. Use this key to sign transactions on Solana, Near, Algorand, and other chains that use the Ed25519 curve.

This method throws:

- `Web3AuthError.noUserFound` if no user session exists.
- `Web3AuthError.ed25519KeyNotFound` if the session has no Ed25519 key. This always happens for users who signed in with an `idToken` (single-factor authentication), because SFA sign-in doesn't return an Ed25519 key.
- `Web3AuthError.ed25519CustomAuthError` if `useSFAKey` is `true` and the dashboard marks the user's auth connection as not default (`isDefault` is `false`).

When you set `useSFAKey` to `true` in `Web3AuthOptions`, this method returns the single-factor authentication (SFA) Ed25519 key.

## Usage

```swift
let ed25519PrivateKey = try web3Auth.getEd25519PrivateKey()

```