System.EncryptHelper.MixUp C# (CSharp) Method

        public static string MixUp(string str)
        {
            // var timestamp = DateTime.Now.ToString(TimestampFormat);
            var timestamp = Guid.NewGuid().ToString();
            var count = str.Length + TimestampLength;
            var sbd = new StringBuilder(count);
            int j = 0;
            int k = 0;
            for (int i = 0; i < count; i++)
            {
                if (j < TimestampLength && k < str.Length)
                {
                    if (i % 2 == 0)
                    {
                        sbd.Append(str[k]);
                        k++;
                    }
                    else
                    {
                        sbd.Append(timestamp[j]);
                        j++;
                    }
                }
                else if (j >= TimestampLength)
                {
                    sbd.Append(str[k]);
                    k++;
                }
                else if (k >= str.Length)
                {
                    break;

                    // sbd.Append(timestamp[j]);
                    // j++;
                }
            }

            return sbd.ToString();
        }