Security and Privacy
The encryption principle of Fouad Whats encryption?
The encryption principle of Fouad WhatsApp encryption. Common Fouad WhatsApp encryption methods include pseudo-encryption, obfuscation, operation verification, and third-party encryption platform Fouad WhatsApp encryption. The three Fouad WhatsApp encryption effects are different. The editor of Love Encryption will take you to explore the encryption principle of Fouad WhatsApp encryption.
The pseudo-encryption of PP encryption is one of the encryption methods before the release of the Android 4.2.x system. The APK (compressed file) is pseudo-encrypted through java code. The modification principle is to modify the continuous 4-bit bytes and mark them as “P K 01 02” The last 5th byte, odd number means not encrypted, even number means encryption.
Although pseudo-encryption can play a certain role in preventing cracking, there are also problems. First of all, after using pseudo-encryption to encrypt the APK, the market cannot perform security detection on it, resulting in some markets rejecting the upload of such APKs;
Secondly, the encryption and decryption methods of pseudo-encryption have already been announced, which has greatly reduced its security; thirdly, the Android4.2.x system cannot install pseudo-encrypted APKs; finally, pseudo-encryption is only a simple protection for APK, at the java layer. There is no protection for source code packing protection, core so library, resource files, main configuration files, and third-party shelf packages.
Note: The higher version does not support this method, so don’t try to use this encryption method.
The confusion of Fouad WhatsApp encryption is to change the original class name, variable name, and method name with specific meanings into incomprehensible names, such as the method name getUserName programmed with the method name. Code obfuscation only increases the difficulty of reading Fouad WhatsApp code, and has no substantial effect on Fouad WhatsApp security, but it is a necessary step before Fouad WhatsApp encryption.
The runtime verification of Fouad WhatsApp encryption mainly refers to obtaining the signature information locally when the code is started, and then checking the signature information to determine whether the Fouad WhatsApplication is genuine. If the signature information is not genuine, it will prompt piracy or crash directly. Of course you can put the necessary data on the server side.
Crack: Find the part of the smali file to determine whether it is equal. Change to constant true, that is, invalid. In short, after decompiling some apks, as long as it is written in java code, there will always be smil files. For the smil file, if you read it patiently, you can still view some key codes.