为了能够做出正确的选择，你应该考虑以下几个方面:

有没有可能“新用户”不愿意花钱而是使用你的软件? 现有客户是否有可能需要比他们拥有的更多的许可证? 潜在用户愿意支付多少钱? 你想按用户/并发用户/工作站/公司发放许可证吗? 你的软件需要培训/定制才能有用吗?

如果问题5的答案是“是”，那么就不用担心非法拷贝。反正也没用。

如果问题1的答案是“是”，那么首先考虑定价问题(见问题3)。

如果你回答问题2“是”，那么“按使用付费”模式可能会 适合你。

从我的经验来看，按使用付费+定制和培训是最好的保护 为您的软件，因为:

新用户被定价模式所吸引(很少使用->很少付费) 几乎没有“匿名用户”，因为他们需要培训和定制。 没有软件限制会吓跑潜在客户。 现有客户源源不断地提供资金。 由于长期的业务关系，您可以从客户那里得到有价值的发展反馈。

在您考虑引入DRM或混淆之前，您可能会考虑这些要点，以及它们是否适用于您的软件。

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。

但只要有合适的时间框架，代码分析人员都可以解决这些问题。

如果你给人们一个他们能够运行的程序，那么只要有足够的时间，他们也能够对它进行逆向工程。这就是程序的本质。一旦二进制文件可供想要破译它的人使用，您就无法阻止最终的逆向工程。毕竟，计算机必须能够破译它才能运行它，而人类只是一台较慢的计算机。

我不认为任何代码都是牢不可破的，但奖励必须非常棒，才能让人们愿意尝试它。

话虽如此，你还是应该做以下事情:

Use the highest optimization level possible (reverse engineering is not only about getting the assembly sequence, it is also about understanding the code and porting it into a higher-level language such as C). Highly optimized code can be a b---h to follow. Make structures dense by not having larger data types than necessary. Rearrange structure members between official code releases. Rearranged bit fields in structures are also something you can use. You can check for the presence of certain values which shouldn't be changed (a copyright message is an example). If a byte vector contains "vwxyz" you can have another byte vector containing "abcde" and compare the differences. The function doing it should not be passed pointers to the vectors but use external pointers defined in other modules as (pseudo-C code) "char *p1=&string1[539];" and "char p2=&string2[-11731];". That way there won't be any pointers pointing exactly at the two strings. In the comparison code you then compare for "(p1-539+i)-*(p2+11731+i)==some value". The cracker will think it is safe to change string1 because no one appears to reference it. Bury the test in some unexpected place.

尝试自己破解汇编代码，看看哪些是容易的，哪些是困难的。您可以尝试一些想法，使代码更难进行反向工程，并使调试更加困难。

正如很多人已经说过的:在一个普通的CPU上，你不能阻止它们，你只能延迟它们。就像我以前的密码学老师告诉我的那样:你不需要完美的加密，破解密码的代价肯定比获得的代价更大。你的困惑也是一样。

但还有3个注意事项:

It is possible to make reverse engineering impossible, BUT (and this is a very very big but), you cant do it on a conventional cpu. I did also much hardware development, and often FPGA are used. E.g. the Virtex 5 FX have a PowerPC CPU on them, and you can use the APU to implement own CPU opcodes in your hardware. You could use this facility to really decrypt incstuctions for the PowerPC, that is not accessible by the outside or other software, or even execute the command in the hardware. As the FPGA has builtin AES encryption for its configuration bitstream, you could not reverse engineer it (except someone manages to break AES, but then I guess we have other problems...). This ways vendors of hardware IP also protect their work. You speak from protocol. You dont say what kind of protocol it is, but when it is a network protocol you should at least protect it against network sniffing. This can you indeed do by encryption. But if you want to protect the en/decryption from an owner of the software, you are back to the obfuscation. Do make your programm undebuggable/unrunnable. Try to use some kind of detection of debugging and apply it e.g. in some formula oder adding a debug register content to a magic constant. It is much harder if your program looks in debug mode is if it where running normal, but makes a complete wrong computation, operation, or some other. E.g. I know some eco games, that had a really nasty copy-protection (I know you dont want copyprotection, but it is similar): The stolen version altered the mined resources after 30 mins of game play, and suddenly you got just a single resource. The pirate just cracked it (i.e. reverse engineered it) - checked if it run, and volia released it. Such slight behaviour changings are very hard to detect, esp. if they do not appear instantly to detection, but only delayed.

所以最后我想建议: 估算逆向工程人员的收益，将其转化为一些时间(例如，使用最便宜的印度工资)，并进行逆向工程，使时间成本更大。

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。