getKeyChain() {
    $.checkState(this.isKeyChainReady(), 'Key chain is not ready');

    const keyShare = this.#dkg.getKeyShare();
    const rKeyShare = this.#dkg.getReducedKeyShare();
    const commonKeyChain = DklsTypes.getCommonKeychain(keyShare);

    return {
      privateKeyShare: keyShare,
      reducedPrivateKeyShare: rKeyShare,
      commonKeyChain: commonKeyChain
    };
  }
Get the keychain
@returns {{ privateKeyShare: Buffer, reducedPrivateKeyShare: Buffer, commonKeyChain: string }} Keychain object