VegenereCipher String Crypter

Function VigenereExEncrypt(sSource, sKey: String; bDecrypt: Boolean = False; iTableSize: Integer = 94): String;
var
 i, iPosText, iPosKey: Integer;
 sTable: string;
begin
//Create our Cipher Table
 i:= 32;
  While i <= (iTableSize + 32) do
   Begin
    sTable:= ConCat(sTable, Chr(i));
    inc(i);
   end;

//Make the key the same size or greater than the Source
 while Length(sSource) >= Length(sKey) do
   sKey:= ConCat(sKey,sKey);

//Remove Line Feed & Carrage Returns from Cipher
 i:=0;
  while i<=Length(sSource) do
    if (sSource[i]=Chr(10)) or (sSource[i]=Chr(13)) then
     Delete(sSource, i, 1)
    else
     Inc(i);
{Uncomment if you need to remove spaces
//Remove Spaces from Cipher
 i:=0;
  while i<=Length(sSource) do
    if sSource[i]=' ' then
     Delete(sSource, i, 1)
    else
     Inc(i);
}

//Vegenere Encryption/Decryption routine
 i:= 1;
  while i <= Length(sSource) do
   Begin
    iPosText  := pred(pos(sSource[i],sTable));
    iPosKey   := pred(pos(sKey[i],sTable));
//Encrypt or Decrypt(Default is Encrypt)
    Case bDecrypt of
     False: Result    := Result + sTable[((iPosText  + iPosKey) mod iTableSize) + 1];
     True : Result    := Result + sTable[(((iPosText + iTableSize) - iPosKey) mod iTableSize) + 1];
    end;
    inc(i);
   end;
end;

Beispiele :

// Crypt
procedure TForm1.Button1Click(Sender: TObject);
begin
	Memo1.Text:= VigenereExEncrypt(Trim(Memo1.Text), Edit1.Text, True);
end;

// Decrypt
procedure TForm1.Button2Click(Sender: TObject);
begin
	Memo1.Text:= VigenereExEncrypt(Trim(Memo1.Text), Edit1.Text);
end;