>>:) Bruce Schneier would argue that if there is no key involved then its encoding rather than encryption. A key taken from the total keyspace provides the random factor (crypto-variable) which is used in an algorithm to produce the cipher text. The same algorithm but with a different key produces a different cipher text for any given plain text. Encoding always produces the same cipher text for any given plain text because there is no key involved.
>>
>>
>
>I don't agree. The only difference is:
>- on encoding the key+algorithm is known
>- on encryption the key+algorithm is unknown

There is no key used in encoding VFP programs or, if there is one, then it is distributed with all VFP applications and is the same for all VFP aplications which therefore makes the use of a key pointless and not meaningfull.

I agree if one does not know the encoding algorithm then it is like encryption - I concede this point. However, the cryptanalysis of encrypted file is far harder than with encoded file due to the addition of the crypto-variable. You can know the algorithm of both the encoding and the encryption methods. In the case of encoding all files can be then decoded. In the case of encryption one still requires the key as well as knowledge of the algorithm.



>A example:
>JPEG is a BMP encoded
>but until you don't know the algorithm of coding,
>the JPEG it is a BMP encrypted.
>
>You calls Bruce and say to it of to decode a JPEG without knowing the specifications.
>
>To this point the question is:
>who has written Refox
>- they has decoded the bytecodes of VFP
>or
>- has made a reverse engineering of the dlls of VFP
>(where a bytecodes decompiler exists).
>
>The world is full of products legal been made with illegal methods.

I agree with that :) However, I think that by performing a series of compilations of given VFP sample/test programs and analysis of the resulting encoded program would result in understanding the algorithm that produces the one from the other. This would not, imo, require reversing the VFP dll's imho but I stand to be corrected.