Java jar package Encryption and use

Because of the project requirements (although I think the code I wrote is not technically advanced ...) ), a well-written jar package requires some encryption

There are two ways to do this, a wonderful flower, a universal

1. Modify the jar file directly:

Specific steps:

Inserting code into code that does not run

1     Private class invalid{2         Private Invalid () {3             4         }5     }

Use Eclipse to package files, right-click Export > Java > JAR file > Finish

Open the jar package using the decompression software. Notepad opens ... $Invalid. class file, remove the D inside

　　# Best to save the outside, and then the inside of the deletion and then dragged in, seemingly cannot be saved directly

Encryption Effect:

It seems that after unpacking the class file can still be cracked

Method defects:

Above

2. Using the Proguard clutter tool

Specific steps:

　　Download Proguard

Recommended Download 5. x version, which is more compatible with JAVA8, and 4. x version and JAVA7 compatible

　　# Otherwise there will be an error unsupported class version number [52.0]

can be downloaded on csdn (http://download.csdn.net/download/kong_gu_you_lan/9637131)

　　# because the next one has done a long reward mission. There is a mailbox verification success out of the two words is what, directly filled out "login", haha

Unzip after download, open Proguard5.x>bin>proguardgui.bat.

　　Using Proguard

on the left input/output, add input on the right adds the need to encrypt the jar package, add output to name an export jar package, below the library, there is a default Rt.jar, if not introduced what custom jar file, directly this default is good

Left obfuscation, select these items in the diagram, where the 2nd, 3 tick corresponding file a.txt is a confusing function name, B.txt is confusing the class name

　　# In fact, it's just a couple of class names and function names, one row for a name

　　

　　　Left shrinking, top shrink removed.

　　# Otherwise the error will be as follows, the output jar is empty. Did you specify the proper '-keep ' options?

Other default, click left process > Process encryption complete

Encryption Effect:

It's OK

Method defects:

Unable to fight against more powerful anti-compilation software

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Supplement: Just know that the partner uses. NET programming, jar package can not be used, need to convert to DLL format, here also by the way.

Conversion steps:

Download IKVM Conversion Tool http://www.ikvm.net/download.html

Unzip, and set System > Advanced system Settings > Environment variables > System Variables Path: Add bin file paths in IKVM

Conversion command:ikvmc-out:xxxx.dll Xxx.jar

Reference blog:

http://blog.csdn.net/a351945755/article/details/21953651 jar converted to DLL

Java jar package Encryption and use