Function derive_signing_key 

pub fn derive_signing_key(
    mnemonic_str: &str,
    account: u32,
    index: u32,
) -> Result<SigningKey, CoreError>

Derives an Ed25519 signing key from a BIP39 mnemonic at the given account and index.

Uses the MultiversX wallet derivation path: m/44’/508’/{account}‘/0’/{index}

Arguments

• mnemonic_str - BIP39 mnemonic phrase (12 or 24 words)
• account - Account number in the derivation path (typically 0 for relayer, 1+ for stress testing)
• index - Address index within the account

Returns

The Ed25519 signing key, or an error if derivation fails.

Examples

use mx_core::derive_signing_key;

let mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
let key = derive_signing_key(mnemonic, 0, 0).unwrap();