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is there any widely used procedure for hiding readable strings? After debugging my code i found a lot of plain text. I can use some simple encryption (Caesar cipher etc...) but this solution will totally slow down my code. Any ideas? Thanks for help

Ryan Gates
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blackfigure00
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    "but this solution will totally slow down my code." Have you benchmarked and confirmed this? Also, note that if, at any time, your program has to use the decrypted strings, then someone reverse-engineering it can read them also. – Jonathon Reinhart Jun 01 '13 at 19:15
  • What level of encryption do you want? ROT13 is pretty easy and fast, and the result is not human readable, but anyone can decrypt if they really wanted to. – jh314 Jun 01 '13 at 19:18
  • @jh314 ROT13 is a Caesar cipher. – Carey Gregory Jun 01 '13 at 22:03
  • If something as simple as a Caesar cipher is going to slow down your code unacceptably, then nothing will be acceptable since simple ciphers like Caesar ciphers are about as fast as it gets. – Carey Gregory Jun 01 '13 at 22:05
  • possible duplicate: http://stackoverflow.com/questions/1356896/how-to-hide-a-string-in-binary-code – kotlomoy Jun 01 '13 at 22:09
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    If you carry all your strings encrypted but of the same length as the original, (Caesar or even better), and you don't look inside them, I don't see how this will slow your code down anywhere except at the point of input and output of strings, where it hardly matters. If you have to look inside the strings, you may pay a decrypting penalty; unless you measure this you're unlikely to know that is this is a *high* overall cost. – Ira Baxter Jun 01 '13 at 22:16
  • Your best chance is _steganography_ - hide the strings within strings, and add huge amounts of clutter. For example, come up with a table to locate your strings within the collected works of William shakespeare and Julius Caesar, then add those in full, and use index tables. Yes, slows you down even more. – FrankH. Jun 04 '13 at 05:46
  • Why the ansi and iso flags? And what language do you want C or assembly and if assembly what processor? – mmmmmm Jun 10 '13 at 12:41

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No, there is no widely used method for hiding referenced strings.

At some point an accessed string would have to be decrypted and this would reveal the key/method and your decryption becomes just obfuscation. If somebody wants to read all your referenced strings he could easily write some script to just convert them all to be readable.

I can't think of any reason to obfuscate strings like that. They are only visible to someone that analyses your executable. Those people would at the same time also be capable to reverse engineer your deobfuscation an apply it to all strings.

If secrecy of strings is vital to the security of your application, you have to rethink that.

Sidenote: There is no way that deciphering strings in C will slow down your application ...Except your application is full of strings and you do something very inefficient in the deciphering. Have you tested this?

typ1232
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    Even though somebody can analyze the encryptuin, it still can make sense, because it slows down the reverse engineering process. – Devolus Jun 02 '13 at 18:45
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    Not by a second. I'd simply take a memory dump of your _running_ application, it'll have a lot of the "decrypted" strings in it anyway ... – FrankH. Jun 04 '13 at 05:39
  • Parts of the string must be at different addresses. Therefore the dump is useless at this point. Just find the calculation and start reversing. – blackfigure00 Jun 19 '13 at 11:19