Struct MultiKeyAccount 

pub struct MultiKeyAccount { /* private fields */ }

A multi-key account supporting M-of-N threshold signatures with mixed key types.

Unlike MultiEd25519Account, this account type supports mixed signature schemes (e.g., 2-of-3 where one key is Ed25519 and two are Secp256k1).

Example

use aptos_sdk::account::{MultiKeyAccount, AnyPrivateKey};
use aptos_sdk::crypto::{Ed25519PrivateKey, Secp256k1PrivateKey};

// Create a 2-of-3 multisig with mixed key types
let keys = vec![
    AnyPrivateKey::ed25519(Ed25519PrivateKey::generate()),
    AnyPrivateKey::secp256k1(Secp256k1PrivateKey::generate()),
    AnyPrivateKey::ed25519(Ed25519PrivateKey::generate()),
];
let account = MultiKeyAccount::new(keys, 2).unwrap();

println!("Address: {}", account.address());
println!("Threshold: {}/{}", account.threshold(), account.num_keys());

Implementations

impl MultiKeyAccount

pub fn new(private_keys: Vec<AnyPrivateKey>, threshold: u8) -> AptosResult<Self>

Creates a new multi-key account from private keys.

All provided private keys will be used for signing. The threshold specifies how many signatures are required.

Arguments

• private_keys - The private keys (can be mixed types)
• threshold - The required number of signatures (M in M-of-N)

Errors

This function will return an error if:

• No private keys are provided
• The threshold exceeds the number of keys
• The multi-key public key creation fails (e.g., too many keys, invalid threshold)

pub fn from_keys( public_keys: Vec<AnyPublicKey>, private_keys: Vec<(u8, AnyPrivateKey)>, threshold: u8, ) -> AptosResult<Self>

Creates a multi-key account from public keys with a subset of private keys.

Use this when you don’t have all the private keys.

Arguments

• public_keys - All the public keys in the account
• private_keys - The private keys you own, with their indices
• threshold - The required number of signatures

Errors

This function will return an error if:

• The multi-key public key creation fails
• A private key index is out of bounds
• A private key doesn’t match the public key at its index (wrong type or bytes)

pub fn view_only( public_keys: Vec<AnyPublicKey>, threshold: u8, ) -> AptosResult<Self>

Creates a view-only multi-key account (no signing capability).

Errors

Returns an error if the multi-key public key creation fails (e.g., no keys provided, too many keys, invalid threshold).

pub fn address(&self) -> AccountAddress

Returns the account address.

pub fn public_key(&self) -> &MultiKeyPublicKey

Returns the multi-key public key.

pub fn num_keys(&self) -> usize

Returns the number of keys in the account.

pub fn threshold(&self) -> u8

Returns the signature threshold.

pub fn num_owned_keys(&self) -> usize

Returns the number of private keys we have.

pub fn can_sign(&self) -> bool

Checks if we can sign (have enough private keys to meet threshold).

pub fn owned_key_indices(&self) -> Vec<u8>

Returns the indices of the private keys we own.

pub fn key_types(&self) -> Vec<AnyPublicKeyVariant>

Returns the key types for each index.

pub fn sign_message(&self, message: &[u8]) -> AptosResult<MultiKeySignature>

Signs a message using the owned private keys.

Will use up to threshold keys for signing.

Errors

Returns an error if we don’t have enough private keys to meet the threshold.

pub fn sign_with_indices( &self, message: &[u8], indices: &[u8], ) -> AptosResult<MultiKeySignature>

Signs a message using specific key indices.

Errors

This function will return an error if:

• Not enough indices are provided to meet the threshold
• We don’t own a private key at one of the specified indices

pub fn verify( &self, message: &[u8], signature: &MultiKeySignature, ) -> AptosResult<()>

Verifies a signature against a message.

Errors

Returns an error if signature verification fails (e.g., invalid signature, insufficient signatures, signature mismatch).

pub fn auth_key(&self) -> AuthenticationKey

Returns the authentication key for this account.

pub fn aggregate_signatures( signatures: Vec<(u8, AnySignature)>, ) -> AptosResult<MultiKeySignature>

Collects individual signatures into a multi-key signature.

Errors

This function will return an error if:

• No signatures are provided
• Too many signatures are provided (more than 32)
• Signer indices are out of bounds or duplicated

pub fn create_signature_contribution( &self, message: &[u8], key_index: u8, ) -> AptosResult<(u8, AnySignature)>

Creates an individual signature contribution.

Errors

Returns an error if we don’t have a private key at the specified index.

Trait Implementations

impl Account for MultiKeyAccount

fn address(&self) -> AccountAddress

Returns the account address.

fn public_key_bytes(&self) -> Vec<u8>

Returns the public key bytes.

fn sign(&self, message: &[u8]) -> AptosResult<Vec<u8>>

Signs a message and returns the signature bytes.

fn authentication_key(&self) -> AuthenticationKey

Returns the authentication key.

fn signature_scheme(&self) -> u8

Returns the scheme identifier for this account type.

impl Debug for MultiKeyAccount

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for MultiKeyAccount

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<MultiKeyAccount> for AnyAccount

fn from(account: MultiKeyAccount) -> Self

Converts to this type from the input type.