Artigos Delphi Funcao para criptografar e descriptografar uma string. 

function Criptografar(wStri: String): String;
var Simbolos : array [0..4] of String;
x            : Integer;
begin
        Simbolos[1]:='ABCDEFGHIJLMNOPQRSTUVXZYWK ~!@#$%^&*()';
        Simbolos[2]:= 'ÂÀ©Øû׃çêùÿ5Üø£úñѪº¿®¬¼ëèïÙýÄÅÉæÆôöò»Á';
        Simbolos[3]:= 'abcdefghijlmnopqrstuvxzywk1234567890';
        Simbolos[4]:= 'áâäàåíóÇü龶§÷ÎÏ-+ÌÓ߸°¨·¹³²Õµþîì¡«½';

        for x := 1 to Length(Trim(wStri)) do 
		begin
                if pos(copy(wStri,x,1),Simbolos[1])>0 then
                Result := Result+copy(Simbolos[2],
                          pos(copy(wStri,x,1),Simbolos[1]),1)

                else 
				if pos(copy(wStri,x,1),Simbolos[2])>0 then
                   Result := Result+copy(Simbolos[1],
                             pos(copy(wStri,x,1),Simbolos[2]),1)

                else 
				if pos(copy(wStri,x,1),Simbolos[3])>0 then
                   Result := Result+copy(Simbolos[4],
                             pos(copy(wStri,x,1),Simbolos[3]),1)
							 
                else 
				if pos(copy(wStri,x,1),Simbolos[4])>0 then
                   Result := Result+copy(Simbolos[3],
                          pos(copy(wStri,x,1),Simbolos[4]),1);
        end;
end;