Re: encryption of strings

Michael Rothwell wrote:
>
> Do you have an example of this code? I would be curious to see it.
>
> Thanks
>
> Michael.
>
> Connor McDonald wrote:
>
> > Clinique wrote:
> > >
> > > Hi everybody,
> > > I am searching for a possibility to encrypt string data types which serve as
> > > passwords in a database table for user management.
> > > Does Oracle offer some kind of procedure for encryption?
> > > Susanne
> >
> > Have a look at Thomas's solution...If you require DE-cryption as well as
> > encryption, you can try the following:
> >
> > Have a (secret) key of (say) 30 chars
> > For each char in string
> > - get ascii val of char
> > - get ascii val of i'th char in key
> > - exclusive-or the two values
> > - chr() the resultant value - this is the 'encrypted' char
> >
> > The resultant encryted string is relatively difficuly to break. To
> > decrypt, just run encyrption again.
> >
> > HTH
> > --
> > ===========================================
> > Connor McDonald
> > http://www.oracledba.co.uk
> >
> > We are born naked, wet and hungry...then things get worse

I don't have the code with me, but off the cuff (ie full of compile errors I suspect):

procedure encode(p_string varchar2, p_code out varchar2) is

  v_key varchar2(60) := 'My secret key';
  v_result varchar2(500);
  v_each_byte number(3);
  v_each_key_byte number(3);

--
-- Make sure the key is at least 30 chars long
-- 
  while length(v_key) < 30 loop
    v_key := v_key || v_key;
  end loop;
  v_key := substr(v_key,1,30);
--
-- For each char in the string
--
  for i in 1 .. length(p_string) loop
--
-- get the ascii vals of the char, and its equivalent in the key
-- 
      v_each_byte := ascii(substr(p_string,i,1));
      v_each_key_byte := ascii(substr(v_key,mod(i,30)+1,1));
--
-- xor the two ascii values and convert back to a char byte
--
      v_result :=  v_result ||
       chr(v_each_byte + v_each_key_byte -
bitand(v_each_byte,v_each_key_byte));
  end loop;
  p_code := v_result;
end;  

Naturally you would want to wrap the PL/SQL so that no-one can see your
key.

HTH
-- 
===========================================
Connor McDonald
http://www.oracledba.co.uk

We are born naked, wet and hungry...then things get worse