/// <summary>Generate a salt.</summary>
/// <param name="saltLength">Length of the salt to generate</param>
/// <param name="logRounds">The log2 of the number of rounds of hashing to apply. The work factor therefore increases as (2 ** logRounds).</param>
/// <returns>An encoded salt value.</returns>
public static string GenerateSalt(int saltLength = 16, int logRounds = 10)
{
    var randomBytes = new byte[saltLength];
    RandomNumberGenerator.Create().GetBytes(randomBytes);

    var rs = new StringBuilder((randomBytes.Length * 2) + 8);

    rs.Append("$2a$");
    if (logRounds < 10) rs.Append('0');
    rs.Append(logRounds);
    rs.Append('$');
    rs.Append(EncodeBase64(randomBytes, randomBytes.Length));

    return rs.ToString();
}