Free UPX Portable

[Vortex]

Free UPX is an advanced graphical interface for the UPX (Ultimate Packer for eXecutables). It allows you to compress (and decompress) files produced according to Microsoft Portable Executable and COFF Specification (EXE, DLL, OCX, BPL, CPL and other). Free UPX is freeware for personal and business use.

http://portableapps.com/apps/utilities/free_upx_portable

[Gunther]

Hi Erol,

thank you forb the link.  :t It's a good tool.

Gunther

[hutch--]

Unless they have changed their quirky licence, I would advise against using UPX because while it usually produced a good compression ratio and the unpacking stub was fast, they impose unusual conditions on non GPL binaries. They claim they own the binary once compressed with UPX and they prohibit altering the compression stub so that it cannot be unpacked.

Sad to say this is a free kick for the virus idiot fringe who can use UPX to unpack your executable code, add a virus to it then repack it using UPX.

I recommend Jeremy Collake's PECompact, free for personal use and no licence restrictions.

[dedndave]

not free any more
he wants $150   :(

[Magnum]

I have his source code.

I know he worked hard, but ....

For free.

Andy

[dedndave]

i guess if i really wanted one, i could write my own
it's not rocket science - and, mine would be unique
you've seen some of my code
if you want to unpack, you better know your way around assembly language pretty well   :P

[Magnum]

I know you could do a good job.

Dollar signs is not a priority for many people who want to help.

[hutch--]

Yes the free version is gone but commercial realities must come into play if the product is continually maintained. I have known Jeremy Collake for many years and he is very cluey on PE binaries and compatibility with a variety of AV scanners. If you are going to release commercial software and it can take advantage of executable compression, then the cost is no big deal. My main usage is load time, a compressed executable loads more quickly and generally loads the entire executable in memory without paging parts of it which improves performance.

[dedndave]

i can see how it may load faster, if you don't include the time it takes to unpack   :P
let's face it, the motivation is obfuscation
as has been stated many times, if it can be packed, it can be unpacked
in googling around for free versions (un-cracked, of course), i noticed the PEcompact unpackers are still free - lol
not that i really care - just an observation

[hutch--]

The difference is that unpacking in memory is a lot faster than reading from a disk but the real gain is in loading the complete executable instead of paging bits of it as it is called. Yes you can unpack most compressed executables but its not an automatic process, is highly skill based and rarely ever produces the same size executable when recompressed and that is IF it can be recompressed. you could get an early UPX compressed EXE to run (before they added the decompression stub) but it was never a valid Win32 file, the more mess it makes of the PE header and sections, the less chance there is of recompressing it.