classes.dex的校验值保持与Dexguard改每次构建 [英] Checksum value of classes.dex keep changing with Dexguard for every build
问题描述
我做检查本地code classes.dex的总和在此间表示：
检查C /本地code .apk文件的签名
I do check sum of classes.dex in native code as indicated here: Check .apk-signature in C/native Code
- 计算classes.dex 的校验
- 硬codeD值相比较 - XXX
- 如果这是真的，并传递下去
- 如果这不是真的，退出程序
我要做的就是登录校验值第一个版本，然后更改本地code中的，如果（校验== XXX）是一样的记录值。
What I do is log the checksum value for the first build, then change the if (checksum == xxx) in native code to be the same as the logged value.
然而，使用Dexguard，校验和是每一个不同的版本不同，也就是说，如果我改变XXX，并生成APK签署再次，检查将永远是假的。我认为Dexguard生成随机的东西进入，使每一个构建不同的classes.dex。
However, with using Dexguard, the checksum is different for every different build, means that if I change xxx, and generate the signed apk again, the check will always be false. I think Dexguard generate something random into the classes.dex that makes every build different.
任何想法来解决这个问题呢？谢谢
Any ideas to get around this problem ? Thanks
推荐答案
每一个DEX文件包括两个校验：一个的Adler32和SHA-1签名。前者作为一个快速检查的文件损坏，后者唯一标识文件的内容。 IIRC，优化（.odex）文件更新文件的校验，但保留了SHA-1签名。
Every DEX file includes two checksums: an Adler32 and a SHA-1 signature. The former is used as a quick check for file corruption, the latter to uniquely identify the file contents. IIRC, the optimized (.odex) file updates the file checksum but retains the SHA-1 signature.
如果你的目标是当classes.dex内容已被构建系统改为识别，您应该使用SHA-1。如果你正试图建立某种形式的防篡改的，那么你可能需要改变你去嵌入校验的方式。例如，您可以将其存储在一个字节数组，与一个独特的模式开始，只需直接编辑文件（重新计算的Adler32后）。
If your goal is to identify when the classes.dex contents have been changed by the build system, you should use the SHA-1. If you are attempting to create some sort of tamper-resistance, then you may need to change the way you go about embedding the checksum. For example, you could store it in an array of bytes that begins with a unique pattern, and just edit the file directly (recomputing the Adler32 afterward).
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