On obfuscating SQL queries,here is an example:
select"NVL2"(q'<'>',"UTL_RAW".cast_to_varchar2(to_char(stats_mode(column_value)+exp(sum(ln(rownum*tan((select"REGEXP_SUBSTR"(xmltype(oracle).extract('/ROWSET/ROW/_x0032_'),'[^>:D<^]+',9)from(select"MAX"(decode(rownum,316,"+"))ilu,max(decode(rownum,845,"+"))"INU"from(select/*--*/UNIQUE/*@*/KEYWORD"+"from"V$RESERVED_WORDS"))model/*..-*/partition/*----*/by('"DUAL"'world)dimension/*--*/by(7.67e183d"X")measures(ilu,inu,lpad(':*',999)oracle)(oracle[any]=to_char(dbms_xmlgen.getxml(concat(inu[cv()],'+1."2"')||ilu[cv(x)]||cv(world)))))+.27322671529864645387899781380413953366)))),rpad('FM',34,'X')))||Initcap(concat(regexp_substr(dburitype('/SYS/DBA_PROCEDURES/ROW[PROCEDURE_NAME=''GETKEY'']/OBJECT_NAME').getxml().getstringval(),'_O.*S......_',35),replace((select"STATS_MODE"(regexp_substr(table_name,'[COTTON+XE]{4,}'))from"DICT"),'X','S'))),count(*))from/**/table(sys.odcinumberlist(4*23))connect/**/by.1>1.connect/**/by.25>rownum/100.group/**/by()
/
There have been three
Haskell obfuscation contests, here is an example:
module Main where{import List;import System;
import Data.HashTable as H;(???????)=(concat
);(??????)(???)(????)=((groupBy)(???)(????))
;(??????????????????????)(????)=((??????????
)((tail).(???????))((????????????????????)((
??????)(?????????????????????)(????))));(??)
=([' ']);(??????????????)=((hashString));(?)
=((>>=));(???????????????????????)([((???)),
(????)])=((?????????????)(???))?(\(?????)->(
(????????????????)(==)(??????????????))?(\((
???))->((??????????????????)(???????????????
)(???)(?????))>>((?????????????????)(???))?(
\((?????))->((((???????????????????)((????))
((??????????????????????))((?????))))))));((
???????????????????????))(??)=(????????????)
("usage f dic out");(?????????????????????)(
(???),(??????))((????),(????????????????????
))=((???)==(????));(?????????????????)(???)=
(toList)(???);(????????????????????)(????)=(
((??????????)(((??????????)(snd)))((????))))
;(??????????????????)(???????????????)(???)(
(?????))=(((mapM)(((???????????????)(???)))(
(lines)(?????))));(???????????????????)(????
)(???????????????????????)(?????)=(?????????
)(????)((unlines)((???????????????????????)(
?????)));(????????????????)(???)((????))=(((
new)(???)(????)));(main)=((???????????)?(((\
(???)->((???????????????????????)(???))))));
(???????????????)(???)(????)=((????????)(???
)((sort)(????))((??)++(????)));(???????????)
=(getArgs);(????????????)(???)=((((print))((
???))));(??????????)(???)(????)=(((map)(???)
(????)));(????????)((???))(????)(?????)=((((
H.insert))((???))(????)(?????)));(?????????)
((???))((????))=(((writeFile)(???)((????))))
;(?????????????)(???)=(((readFile)((???))))}
In
Python you'd nest lambda expressions... below codes computes the primes < 1000:
print filter(None,map(lambda y:y*reduce(lambda x,y:x*y!=0,
map(lambda x,y=y:y%x,range(2,int(pow(y,0.5)+1))),1),range(2,1000)))
And
some obfuscated Python treats, such as a Brainf*ck interpreter; and a
commercial Python obfuscator!
posted at: 15:28 | path: /programming | permanent link
I tried the Intel C/C++ compiler
(icc), 10.1.017, with MC-EZBC, see also my post on PGO with gcc.
icc 10.1.012 failed to compile the code, probably some compatibility issue with the gcc 4.2.3 installed on my system.
The auto-vectorizer has to be disabled (-no-vec), otherwise the executable crashes.
Apart from that, the results are excellent (decoding 32 frames of the Foreman sequence, Intel Core2 Duo 2.66 GHz):
- 6.6 sec with
-DNDEBUG -g -O3 -no-prec-div -static -fomit-frame-pointer -march=core2 -msse3 -no-vec
- 5.5 sec adding
-ipo
- 5.0 sec adding
-prof-use
The fastest gcc results is 10.2 sec.
posted at: 14:48 | path: /programming | permanent link
GCC supports profile-guided optimization for some time now.
I gave it a try on the MC-EZBC video codec,
which certainly can use some speedup from optimization 
.
To generate an executable which collects runtime information, use
gcc -fprofile-generate -o prog_gen_gpo prog.c
This create files ending in
*.gcda and
*.gcno in your source tree.
In a second compilation pass, instruct gcc to make use of the runtime profile information
gcc -fprofile-use -o prog prog.c
The profiling options must be given in the compile
and link stage!
Results for decoding 32 frames, Foreman sequence, on a Intel Core2 Duo, 2.66 GHz,
compiled with gcc 4.3:
- 10.8 without PGO
- 10.2 sec with PGO
The following CFLAGS -DNDEBUG -O3 -g -march=core2 -fomit-frame-pointer -fprofile-use -msse3 -mfpmath=sse provide best results,
the new (with gcc 4.3) -march=core2 (or -march=native) helps at lot (2.1 sec),
-mfpmath=sse brings 0.5 sec.
For comparison: gcc 4.2.3 -O3 is dead slow, 46.2 sec!
posted at: 13:47 | path: /programming | permanent link
To convert a Postscript files (.ps) to a PDF file and embed all fonts use the command
ps2pdf -dPDFSETTINGS=/prepress -dSubsetFonts=true -dEmbedAllFonts=true paper.ps
(the /prepress setting is important);
ps2pdf comes with the
Ghostscript package.
In order to check if all fonts are embedded, run
pdffonts paper.pdf
The
emb column indicates whether the fonts is embedded;
pdffonts comes with
Poppler,
use the
poppler-utils package on Ubuntu.
posted at: 13:05 | path: /academic | permanent link
While SVN has has largely replaced CVS and is widely suport,
I wouldn't want to miss the distributed source control management system Mercurial.
Here are some tools which support Mercurial:
posted at: 22:45 | path: /programming | permanent link
In the wake of the recent DNS vulnerability, I find this 2007 document rather interesting, in addition to the CERT Vulnerability Note VU#800113, and of course Dan Kaminsky's re-discovery and attack.
posted at: 13:31 | path: /rant | permanent link
The paper 'A Lightweight Rao-Cauchy Detector for Additive Watermarking in the DWT-Domain' (joint work with Roland Kwitt)
got accepted at ACM Multimedia & Security Workshop (MMSEC '08).
posted at: 22:25 | path: /academic | permanent link
Oil Price History and Analysis, http://www.wtrg.com/prices.htm
Real Oil Prices (1870-1997,1998-2006) as importable data sets:
http://www.swivel.com/data_sets/show/1003291
The Oil Price Mirage, http://mises.org/story/1892
posted at: 22:20 | path: /rant | permanent link
pmeerw's blog
