RE: UTL_RAW and slowness

[Jamadagni, Rajendra]

Jared, I know, but this is a legacy code that is attached to a hardware ticker tape that scrolls message that it received. The code I supplied has couple of other operations removed (for obvious reasons) but these steps are required because the hardware chip in the ticker box won't recognize it.

 

BTW, I have successfully used RC4 from your site in past to implement encryption.

 

HTH Some

Raj

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Thursday, October 23, 2003 7:06 PM
To: [EMAIL PROTECTED]
Cc: Jamadagni, Rajendra
Subject: Re: UTL_RAW and slowness
Importance: High

Raj,

I'll try to be tactful here, but that isn't encryption. It only looks like
encryption, and is in fact very easy to break.

Check out the article at http://www.cybcon.com/~jkstill/util/encryption/encryption.html

There are PL/SQL implementations of RC4 and Blowfish there. RC4 is a stream cipher
and Blowfish is a block cipher.  Either would suit your purpose.

Blowfish is there courtesy of Craig Munday.

RC4 is there courtesy of a leak at RSA, but it's in the public domain now, so that
doesn't matter anymore.

Also check Pete Finnigans site:  http://www.petefinnigan.com/

HTH

Jared

"Jamadagni, Rajendra" <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED]  10/23/2003 02:54 PM  Please respond to ORACLE-L

To:        Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>         cc:                 Subject:        UTL_RAW and slowness

Hi all,

I am experimenting with a block of pl/sql code (wrote myself) that uses utl_raw to perform xor operation. (Note to Jared and Mladan, I can't use Perl on production boxes, so don't even go there).

I take a message, encrypt 1 character send it out on a wire using utl_tcp. After every 128 bytes, I flush the tcp connection. While this works fine and within our acceptable range for smallish messages (up to 20-25K in size), it nearly kills itself when working with larger messages (80k+).

Initially I could encrypt 128 characters (including conversion from/to utl_raw) in about 50ms. Bt this increase progressively. When I reach about 98000 to 99000 range, it takes about 16 seconds to encrypt 128 characters.

I have logged tar with Oracle, but does anyone know if one could do a block encryption (can't use standard algorithms, this is custom) like encrypt 128 characters at a time instead of 1 ...

The skeleton code looks like this ...

msglen := LENGTH (msg_text);
nCharsSent := 0;
p('Encrypting data...');
FOR i IN 1 .. msglen
LOOP
 ntcpchar := ASCII (SUBSTR (msg_text, i, 1));
 r_chr    := utl_raw.cast_to_raw(CHR(ntcpchar));
 nenctcpchar := TO_NUMBER(utl_raw.bit_xor(r_chr,r_key),'xxxx');
 tcpmsglen := UTL_TCP.write_text (gv_tcp_conn, CHR(nenctcpchar), NULL);
  nCharsSent := nCharssent + 1;
 IF MOD(ncharssent,128) = 0 THEN
   p('Before Flush ...');
   UTL_TCP.FLUSH (gv_tcp_conn);
   p('Connection Flushed at ' || ncharssent);
 END IF;
 --    
END LOOP; -- FOR i IN 1 .. msglen

where p is a procedure that dumps supplied text to a trace file with a timestamp that is up to 1 ms resolution. BTW this is a 9202 box. Also when it starts getting slow, using "nmon" I can see that this process is hogging a CUP at 99-100%. Of course this is a dev box, but my SA will not like this on a production box.

Any ideas?
Thanks in advance
Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot com
All Views expressed in this email are strictly personal.
QOTD: Any clod can have facts, having an opinion is an art !

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