>>>>>>>>>>>>>I am testing your code and mine code and neither one works :). I am sure it is me. Here is how I test it, please let me know if this is the correct approach:
>>>>>>>>>>>>>

>>>>>>>>>>>>>string cTest1 = "ABC123";
>>>>>>>>>>>>>string cTest1Encr;
>>>>>>>>>>>>>string cTest1Decr;
>>>>>>>>>>>>>cTest1Encr = Encrypt( cTest1, "123abc");
>>>>>>>>>>>>>cTest1Decr = Encrypt( cTest1Encr, "123abc");
>>>>>>>>>>>>>

>>>>>>>>>>>>>
>>>>>>>>>>>>>Shouldn't cTest1Decr show "ABC123"?
>>>>>>>>>>>>
>>>>>>>>>>>>Aren't you encrypting the values instead of decrypting the 2nd?
>>>>>>>>>>>
>>>>>>>>>>>The second parameter is the password string. The first one is the value.
>>>>>>>>>>
>>>>>>>>>>Too late to play tonight - I'll get back to you in the morning (my morning :-} )
>>>>>>>>
>>>>>>>>Encoding problem when char values > 128. This should work. Didn't look at your code I'm afraid:

using System;
>>>>>>>>using System.Collections.Generic;
>>>>>>>>using System.Linq;
>>>>>>>>using System.Text;
>>>>>>>>
>>>>>>>>namespace Cipher
>>>>>>>>{
>>>>>>>>    public class Cipher
>>>>>>>>    {
>>>>>>>>        private const int PwMinNum = 1000;
>>>>>>>>
>>>>>>>>        public string Encrypt(string tcStr, string tcPassword)
>>>>>>>>        {
>>>>>>>>            byte[] tcStrBytes = Encoding. GetEncoding(1252).GetBytes(tcStr);
>>>>>>>>            int tcStrLength = tcStrBytes.Length;
>>>>>>>>
>>>>>>>>            string lcPassword = tcPassword + ((char) 0).ToString();
>>>>>>>>            byte[] lcPasswordBytes = Encoding.GetEncoding(1252).GetBytes(lcPassword);
>>>>>>>>
>>>>>>>>            int lnPassLen = lcPasswordBytes.Length;
>>>>>>>>            int lnPassPos = 0;
>>>>>>>>            int lnPassNum = ((CipherGetPnum(lcPasswordBytes)/997 - 1)%254) + 1;
>>>>>>>>
>>>>>>>>            byte[] bytes = new byte[tcStr.Length];
>>>>>>>>
>>>>>>>>            for (int i = 0; i < tcStrLength; i++)
>>>>>>>>            {
>>>>>>>>                int lnNum01 = ((lnPassNum + (i - tcStrLength)) - 1);
>>>>>>>>                lnPassNum = (Math.Abs(lnNum01)%254)*Math.Sign(lnNum01) + 1;
>>>>>>>>                var lnByte = tcStrBytes[i] ^ (lnPassNum ^ lcPasswordBytes[lnPassPos]);
>>>>>>>>                bytes[i] = lnByte==0 ? tcStrBytes[i] : (byte) (lnByte & 0xFF);
>>>>>>>>                lnPassPos = lnPassPos > lnPassLen ? 0 : lnPassPos + 1;
>>>>>>>>            }
>>>>>>>>            return Encoding.GetEncoding(1252).GetString(bytes);
>>>>>>>>        }
>>>>>>>>
>>>>>>>>        private int CipherGetPnum(IEnumerable<byte> ascii)
>>>>>>>>        {
>>>>>>>>            int liRet = 1 + ascii.Select((t, i) => t + i).Sum();
>>>>>>>>            while (liRet < PwMinNum)
>>>>>>>>            {
>>>>>>>>                liRet = liRet << 1;
>>>>>>>>            }
>>>>>>>>            return liRet;
>>>>>>>>        }
>>>>>>>>    }
>>>>>>>>}

>>>>>>>
>>>>>>>Thank you very much. Your code works; almost 100%. Except when a string that you are trying to encrypt has more than 2 spaces
>>>>>>>(e.g."ABC123 ", 3 spaces after '3'), it produces error. Btw, if the string has only 2 empty spaces, no error. E.g. "ABC123 " (two spaces after 3), no error.
>>>>>>
>>>>>>Duh. Can't count - I was exceeding password length :-{ .
>>>>>>Two changes should fix:

int lnPassLen = lcPasswordBytes.Length - 1;
>>>>>>//and
>>>>>>lnPassPos = lnPassPos == lnPassLen ? 0 : lnPassPos + 1;

>>>>>
>>>>>Can you please post the final version with all the corrections?
>>>>>
>>>>>Also, perhaps it will be nice to add to Downloads section here as well.
>>>>>
>>>>>Thanks again.
>>>>
>>>>Don't know if I kept a copy. Dmitry may have it ?
>>>
>>>Of course I have it. This code works very well. Thank you.
>>
>>Perhaps, since I don't seem to have kept it, you could send it to Naomi ?
>
>No. She has to ask and say "please" :)

:-}