>>>>>>>>If all this function does is encrypt a password there are lots of examples written in c# out there ( Google is your friend )
>>>>>>>
>>>>>>>I did but so for I could not find a simple enough c# encrypt function that can be "duplicated" in VFP. You see I need a function that would do the same from VFP and c# end.
>>>>>>>Thank you.
>>>>>>
>>>>>>Presumably you mean that the C# version should be usable with strings already encoded using the VFP cipher library that you mentioned?
>>>>>>
>>>>>>Al's pointer to Rick's paper is still valid - you could create a small VFP com interop which could be accessed from .net.
>>>>>>
>>>>>>But which functions of that library do you actually use ? - the core encryption is fairly straightforward.
>>>>>>I took a look at the original C code and it would seem that a C# version should be simple enough to implement......
>>>>>
>>>>>The function cipher() I am using in VFP code is written in VFP; not in C. Maybe Sergey also wrote it in C but the one he recommended to me years ago was the VFP function. To be honest, I don't even understand all VFP functions he used in creating the cipher(). So converting/rewriting it to C# would be a great challenge.
>>>>
>>>>The VFP code was based on a C conversion and there's a link to the C source - you might find that easier to convert to C# (or not :-} )
>>>
>>>Do you know where I can find the DLL (I presume tha the C code was built into a DLL) file that uses this C code? And maybe it has the C code there as well.
>>
>>Does this work (not properly tested and could certainly be improved):
using System;
>>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.ASCII.GetBytes(tcStr);
>> int tcStrLength = tcStrBytes.Length;
>>
>> string lcPassword = tcPassword + '0';
>> byte[] lcPasswordBytes = Encoding.ASCII.GetBytes(lcPassword);
>> int lnPassLen = lcPasswordBytes.Length - 1;
>>
>> int lnPassPos = 0;
>>
>> string lcStrOut = string.Empty;
>>
>> int lnPassNum = ((CipherGetPnum(lcPassword)/997 - 1)%254) + 1;
>>
>> 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]);
>> lnByte = lnByte & 0xFF;
>> lcStrOut = lcStrOut + (lnByte == 0 ? Convert.ToChar( tcStrBytes[i + 1]) : Convert.ToChar(lnByte));
>> lnPassPos = lnPassPos>=lnPassLen ? 1:lnPassPos + 1;
>> }
>> return lcStrOut;
>> }
>>
>> private int CipherGetPnum(string tcStr)
>> {
>> byte[] ascii = Encoding.ASCII.GetBytes(tcStr);
>> int liRet = 1 + ascii.Select((t, i) => t + i).Sum();
>>
>> while (liRet < PwMinNum)
>> {
>> liRet = liRet << 1;
>> }
>> return liRet;
>> }
>> }
>>}>
>This is my C# code:
>
> public class VfpCipher
> {
>
> public static string Cipher(string cString, string tcPassword)
> {
> string lcPassword;
> int lnPassLen;
> int lnPassPos;
> int iAsciiValue;
> int lnPassNum;
> int lnStrLen;
>
> lnStrLen = cString.Length;
>
> char ChrZero;
> ChrZero = (char)0;
>
> lcPassword = tcPassword + ChrZero.ToString(); // in VFP this was add CHR(0) to the Password string
> lnPassLen = lcPassword.Length;
>
> int[] laPassword = new int[lnPassLen+1];
> for (lnPassPos = 0; lnPassPos < lnPassLen; lnPassPos++)
> {
> // Get one-character from the Password string and store the ASC()/ASCII value of it to the array.
> var charByte = System.Text.Encoding.GetEncoding(1252).GetBytes(lcPassword.Substring(lnPassPos, 1));
> laPassword[lnPassPos] = Convert.ToInt32(charByte[0]);
> }
>
> // Get seed value
> lnPassNum = (int)((((CipherGetPnum(lcPassword) / 997) - 1) % 254) + 1);
>
> int lnByte;
> string lcStrOut = "";
> lnPassPos = 0; // in VFP this is 1 but in C# the array is zero-based.
> int lnNum01;
>
> // Encode/decode each character
> for (int lnInPos=0; lnInPos < lnStrLen-1; lnInPos++)
> {
> // Get new seed value
> lnNum01 = (( lnPassNum + (lnInPos - lnStrLen)) - 1);
> lnPassNum = ( Math.Abs(lnNum01) % 254 ) * Math.Sign(lnNum01) + 1;
>
> // Get the character byte and extract the ASCII value of the character.
> var charByte = System.Text.Encoding.GetEncoding(1252).GetBytes(cString.Substring(lnInPos, 1));
>
> iAsciiValue = Convert.ToInt32(charByte[0]);
> lnByte = (iAsciiValue ^ (lnPassNum ^ laPassword[lnPassPos]));
>
> // Convert signed value to unsigned, if necessary
> lnByte = lnByte & 0xFF;
>
> // If result is zero, use current character
> // Get one character string value of lnByte
> char cOneChar;
> cOneChar = (char)lnByte;
> string sOneChar;
> sOneChar = cOneChar.ToString();
> lcStrOut = lcStrOut + (lnByte.Equals(0) ? cString.Substring(lnInPos, 1) : sOneChar);
>
> lnPassPos = (lnPassPos.CompareTo(lnPassLen-1) >= 0 ? 0 : lnPassPos + 1);
> }
>
> return lcStrOut;
>
> }
>
> public static int CipherGetPnum(string SeedString)
> {
> int liRet = 1;
> int iAsciiValue;
> for (int lnPos = 0; lnPos < SeedString.Length; lnPos++)
> {
> var charByte = System.Text.Encoding.GetEncoding(1252).GetBytes(SeedString.Substring(lnPos, 1));
> iAsciiValue = Convert.ToInt32(charByte[0]);
> liRet = liRet + iAsciiValue + lnPos;
> }
>
> // Note that in Sergey's code the value 1000 is declared as constant.
> do
> {
> liRet = liRet << 1;
> } while (liRet < 1000);
>
> return liRet;
>
> }
> }
>Hmm. Does that work correctly - looks as if you are not processing the last character of the string to be encrypted ?
Not important but you don't need to loop through each character in the string to build an array - GetBytes() against the whole string will do it for you....
