我一直在思考如何保护我的C/ c++代码不被反汇编和逆向工程破坏。通常情况下,在我的代码中,我绝不会宽恕这种行为;然而,为了各种人的安全,我目前正在研究的协议决不能被检查或理解。

现在这对我来说是一个新的主题,互联网并没有真正的资源来防止逆向工程,而是描述了大量关于如何逆向工程的信息

到目前为止我想到的一些事情是:

Code injection (calling dummy functions before and after actual function calls) Code obfustication (mangles the disassembly of the binary) Write my own startup routines (harder for debuggers to bind to) void startup(); int _start() { startup( ); exit (0) } void startup() { /* code here */ } Runtime check for debuggers (and force exit if detected) Function trampolines void trampoline(void (*fnptr)(), bool ping = false) { if(ping) fnptr(); else trampoline(fnptr, true); } Pointless allocations and deallocations (stack changes a lot) Pointless dummy calls and trampolines (tons of jumping in disassembly output) Tons of casting (for obfuscated disassembly)

我的意思是,这些是我想过的一些事情,但它们都可以在适当的时间框架内由代码分析师解决。我还有别的选择吗?


当前回答

看看http://en.wikipedia.org/wiki/Security_by_obscurity#Arguments_against。我相信其他人可能也能给出一个更好的来源,说明为什么通过隐匿性实现安全是一件坏事。

它应该是完全可能的,使用现代加密技术,让您的系统是开放的(我不是说它应该是开放的,只是它可以是),并且仍然具有完全的安全性,只要加密算法没有漏洞(如果您选择了一个好的算法,就不太可能),您的私钥/密码保持私有,并且您的代码中没有安全漏洞(这是您应该担心的)。

其他回答

通过不公开来保证安全并不像比他聪明得多的人所证明的那样有效 我们两个。如果你必须保护你的客户的通信协议,那么你是 道德上有义务使用最好的代码,这些代码是公开的,并由专家全面审查。

这适用于人们可以检查代码的情况。如果您的应用程序是在嵌入式微处理器上运行的,那么您可以选择一个具有密封功能的微处理器,这使得在运行时不可能检查代码或观察更多的琐碎参数,例如当前使用情况。(是的,除了硬件入侵技术,你要小心地拆卸芯片,使用先进的设备来检查单个晶体管上的电流。)

我是x86逆向工程汇编程序的作者。如果你准备感冒的话 惊喜,寄给我你竭尽全力的结果。(通过我的网站联系我。) 在我所看到的答案中,很少有人会给我带来实质性的障碍。如果你想看的话 如何复杂的逆向工程代码工作,你真的应该研究网站 逆向工程挑战。

你的问题需要澄清一下。你怎么能保守协议的秘密,如果 计算机代码可以进行逆向工程吗?如果我的协议是发送一个RSA加密消息(甚至是公钥),通过保持协议的秘密,你能得到什么? 出于所有实际目的,检查器将面对一系列随机比特。

问候阿尔伯特

安布尔说的完全正确。你可以让逆向工程变得更难,但你永远无法阻止它。永远不要相信依赖于防止逆向工程的“安全性”。

That said, the best anti-reverse-engineering techniques that I've seen focused not on obfuscating the code, but instead on breaking the tools that people usually use to understand how code works. Finding creative ways to break disassemblers, debuggers, etc is both likely to be more effective and also more intellectually satisfying than just generating reams of horrible spaghetti code. This does nothing to block a determined attacker, but it does increase the likelihood that J Random Cracker will wander off and work on something easier instead.

安全网哨兵(原阿拉丁)。不过要注意的是——他们的API很烂,文档也很烂,但与他们的SDK工具相比,这两者都很棒。

I've used their hardware protection method (Sentinel HASP HL) for many years. It requires a proprietary USB key fob which acts as the 'license' for the software. Their SDK encrypts and obfuscates your executable & libraries, and allows you to tie different features in your application to features burned into the key. Without a USB key provided and activated by the licensor, the software can not decrypt and hence will not run. The Key even uses a customized USB communication protocol (outside my realm of knowledge, I'm not a device driver guy) to make it difficult to build a virtual key, or tamper with the communication between the runtime wrapper and key. Their SDK is not very developer friendly, and is quite painful to integrate adding protection with an automated build process (but possible).

Before we implemented the HASP HL protection, there were 7 known pirates who had stripped the dotfuscator 'protections' from the product. We added the HASP protection at the same time as a major update to the software, which performs some heavy calculation on video in real time. As best I can tell from profiling and benchmarking, the HASP HL protection only slowed the intensive calculations by about 3%. Since that software was released about 5 years ago, not one new pirate of the product has been found. The software which it protects is in high demand in it's market segment, and the client is aware of several competitors actively trying to reverse engineer (without success so far). We know they have tried to solicit help from a few groups in Russia which advertise a service to break software protection, as numerous posts on various newsgroups and forums have included the newer versions of the protected product.

最近,我们在一个较小的项目上尝试了他们的软件许可解决方案(HASP SL),如果您已经熟悉HL产品,那么这个解决方案就足够简单了。它似乎有效;目前还没有关于盗版事件的报道,但这款产品的需求要低得多。

当然,没有什么保护措施是完美的。如果有人有足够的动机,并且有大量的现金可以烧,我相信HASP提供的保护是可以规避的。

最好的反反汇编技巧,特别是在可变字长指令集上,是在汇编程序/机器代码中,而不是在c中

CLC
BCC over
.byte 0x09
over:

The disassembler has to resolve the problem that a branch destination is the second byte in a multi byte instruction. An instruction set simulator will have no problem though. Branching to computed addresses, which you can cause from C, also make the disassembly difficult to impossible. Instruction set simulator will have no problem with it. Using a simulator to sort out branch destinations for you can aid the disassembly process. Compiled code is relatively clean and easy for a disassembler. So I think some assembly is required.

I think it was near the beginning of Michael Abrash's Zen of Assembly Language where he showed a simple anti disassembler and anti-debugger trick. The 8088/6 had a prefetch queue what you did was have an instruction that modified the next instruction or a couple ahead. If single stepping then you executed the modified instruction, if your instruction set simulator did not simulate the hardware completely, you executed the modified instruction. On real hardware running normally the real instruction would already be in the queue and the modified memory location wouldnt cause any damage so long as you didnt execute that string of instructions again. You could probably still use a trick like this today as pipelined processors fetch the next instruction. Or if you know that the hardware has a separate instruction and data cache you can modify a number of bytes ahead if you align this code in the cache line properly, the modified byte will not be written through the instruction cache but the data cache, and an instruction set simulator that did not have proper cache simulators would fail to execute properly. I think software only solutions are not going to get you very far.

上面这些都是老的和众所周知的,我对当前的工具了解不够,不知道它们是否已经围绕这些事情工作了。自修改代码可能/将使调试器出错,但是人类可以/将缩小问题范围,然后看到自修改代码并解决它。

It used to be that the hackers would take about 18 months to work something out, dvds for example. Now they are averaging around 2 days to 2 weeks (if motivated) (blue ray, iphones, etc). That means to me if I spend more than a few days on security, I am likely wasting my time. The only real security you will get is through hardware (for example your instructions are encrypted and only the processor core well inside the chip decrypts just before execution, in a way that it cannot expose the decrypted instructions). That might buy you months instead of days.

另外,读读凯文·米特尼克的《欺骗的艺术》。这样的人可以拿起电话,让你或同事把秘密交给系统,以为那是公司其他部门的经理、其他同事或硬件工程师。你的安全系统也被破坏了。安全不仅仅是管理技术,还要管理人。

很多时候,担心你的产品被逆向工程是多余的。是的,它可以被逆向工程;但它是否会在短时间内变得如此出名,以至于黑客们会发现它值得逆转。它吗?(对于大量的代码行来说,这项工作不是一个小时间活动)。

如果它真的能赚钱,那么你就应该筹集足够的资金,通过专利或版权等合法途径来保护它。

恕我直言,采取你将要采取的基本预防措施,然后释放它。如果它成为逆向工程的一个点,这意味着你已经做得非常好,你自己会找到更好的方法来克服它。祝你好运。