/// <summary>
        /// Create an account for a specific account index and account name pattern.
        /// </summary>
        /// <param name="password">The password used to decrypt the wallet's encrypted seed.</param>
        /// <param name="encryptedSeed">The encrypted private key for this wallet.</param>
        /// <param name="chainCode">The chain code for this wallet.</param>
        /// <param name="network">The network for which this account will be created.</param>
        /// <param name="accountCreationTime">Creation time of the account to be created.</param>
        /// <param name="newAccountIndex">The optional account index to use.</param>
        /// <param name="newAccountName">The optional account name to use.</param>
        /// <returns>A new HD account.</returns>
        public HdAccount CreateAccount(string password, string encryptedSeed, byte[] chainCode,
                                       Network network, DateTimeOffset accountCreationTime,
                                       int newAccountIndex, string newAccountName = null)
        {
            if (string.IsNullOrEmpty(newAccountName))
            {
                newAccountName = string.Format(Wallet.AccountNamePattern, newAccountIndex);
            }

            // Get the extended pub key used to generate addresses for this account.
            string    accountHdPath    = HdOperations.GetAccountHdPath((int)this.CoinType, newAccountIndex);
            Key       privateKey       = HdOperations.DecryptSeed(encryptedSeed, password, network);
            ExtPubKey accountExtPubKey = HdOperations.GetExtendedPublicKey(privateKey, chainCode, accountHdPath);

            return(new HdAccount
            {
                Index = newAccountIndex,
                ExtendedPubKey = accountExtPubKey.ToString(network),
                ExternalAddresses = new List <HdAddress>(),
                InternalAddresses = new List <HdAddress>(),
                Name = newAccountName,
                HdPath = accountHdPath,
                CreationTime = accountCreationTime
            });
        }
        /// <summary>
        /// Adds an account to the current account root using encrypted seed and password.
        /// </summary>
        /// <remarks>The name given to the account is of the form "account (i)" by default, where (i) is an incremental index starting at 0.
        /// According to BIP44, an account at index (i) can only be created when the account at index (i - 1) contains transactions.
        /// <seealso cref="https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki"/></remarks>
        /// <param name="password">The password used to decrypt the wallet's encrypted seed.</param>
        /// <param name="encryptedSeed">The encrypted private key for this wallet.</param>
        /// <param name="chainCode">The chain code for this wallet.</param>
        /// <param name="network">The network for which this account will be created.</param>
        /// <param name="accountCreationTime">Creation time of the account to be created.</param>
        /// <returns>A new HD account.</returns>
        public HdAccount AddNewAccount(string password, string encryptedSeed, byte[] chainCode, Network network, DateTimeOffset accountCreationTime)
        {
            Guard.NotEmpty(password, nameof(password));
            Guard.NotEmpty(encryptedSeed, nameof(encryptedSeed));
            Guard.NotNull(chainCode, nameof(chainCode));

            int newAccountIndex = 0;
            ICollection <HdAccount> hdAccounts = this.Accounts.ToList();

            if (hdAccounts.Any())
            {
                newAccountIndex = hdAccounts.Max(a => a.Index) + 1;
            }

            // Get the extended pub key used to generate addresses for this account.
            string    accountHdPath    = HdOperations.GetAccountHdPath((int)this.CoinType, newAccountIndex);
            Key       privateKey       = HdOperations.DecryptSeed(encryptedSeed, password, network);
            ExtPubKey accountExtPubKey = HdOperations.GetExtendedPublicKey(privateKey, chainCode, accountHdPath);

            var newAccount = new HdAccount
            {
                Index             = newAccountIndex,
                ExtendedPubKey    = accountExtPubKey.ToString(network),
                ExternalAddresses = new List <HdAddress>(),
                InternalAddresses = new List <HdAddress>(),
                Name         = $"account {newAccountIndex}",
                HdPath       = accountHdPath,
                CreationTime = accountCreationTime
            };

            hdAccounts.Add(newAccount);
            this.Accounts = hdAccounts;

            return(newAccount);
        }