Reverse engineering compiled Xojo programs

[Michel_Bujardet]

@91090:@Nathan Wright

Years ago in the early days of the internet we created a standalone server that had no correction to the outside world except via a custom made parallel cable

By the sam token, IBM 5250 was popular amongst insurance companies because there was no intelligent 5250 terminals that would enable taking the data away. 3270 was considered less secure because emulator cards quickly appeared on PC that allowed snatching data and put it on disk.

It is fascinating to see how companies that could keep their data safe in a non connected local network with diskless terminals connect their precious server to the Internet without quite envisioning the risk.

@91097:@Graham Stephens

Out of curiosity, for the guys that said to split up the data and spread it around the program, would an efficient compiler not put it all together again?

A very very efficient compiler maybe able to optimise repetitive operation on scattered static data. But a compiler is not able to decipher programmer’s intent. So when the key is spread through different methods that fetch and assemble the data dynamically, the compiler cannot predict all that will eventually end up in the same bucket.

Ironically, all the hacker has to discover is where the bucket is, with the gold inside. Even if it exists for a few microseconds.

The Exe to C program reported by Matthew is scary because whatever the complex operations used to assemble the password, the code required to submit a password to decrypt data will always remain rather simple, and therefore easy to spot.

[Nathan_Wright]

@91103:@Michel Bujardet

By the sam token, IBM 5250 was popular amongst insurance companies because there was no intelligent 5250 terminals that would enable taking the data away.

We considered using 5250 but because one of the sponsors of the project was Wang Systems we were told we could not use anything that was IBM

[DaveS]

Wang 2200B
one of the first “real computers” I used back in the '70s

Had 4 of them tied to a central hard disk
Each CPU had 4k of memory, and the HD was 1meg

What was cool about those, was they could use and control a standard cassette tape in the same way big machines controlled a reel-to-reel data tape. A group of us wrote a 32k Startrek that had to page code in and out from a tape that way…

Good times… long ago…

[Nathan_Wright]

[quote=91232:@Dave S]Had 4 of them tied to a central hard disk
Each CPU had 4k of memory, and the HD was 1meg[/quote]

Man you were posh!!! You had something powerful, dont think we had anything so cool, cant ever remember a hard drive being available to us Ah the days of real programming