NODE 8c44e085Re: Weak steganography
karn@qualcomm.com (Phil Karn)Wed, 23 Jun 93 18:19:11 PDT
At 10:45 AM 6/17/93 -0700, Hal Finney wrote:
>Another problem is that encrypted files look different from executable
>files. Encrypted files have a uniform histogram (that is, all 256 different
>possible byte values are equally frequent), but exe files do not.
Not necessarily. If you use pklite or lzexe, you produce an automatically
self-decompressing executable that will appear to have a much flatter
distribution than an ordinary exe file.
What we need is a crypto version of pklite - instead of (or in addition to)
compressing the executable, it encrypts it and sticks a stub decryptor
on the front of the executable. Each time you run it, it prompts you for
a password, decrypts and decompresses the executable and runs it.
Phil
NODE 378d843dcrypto pklite
Douglas Sinclair <dsinclai@acs.ucalgary.ca>Wed, 23 Jun 93 19:49:00 PDT
I have a friend who wrote a gadget called EXELOCK. It will throw
a password stub into the front of an of an EXE file. Now, I'm sure
it doesn't use encryption but just compares the hash of the password to
a stored value. However, I'm sure an IDEA or DES version could be implemented.
As for compression, no need to re-invent the wheel. Simply run pklite
and then run the new EXELOCK on the result.
I'll contact this person and see if I can lay my hands on the source
code for the gadget.
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