17 votes

How are Apple App Store Apps encrypted?

When you download an app from the App Store, Apple injects a special 4196 byte long header into the signed binary encrypted with the public key associated with your iTunes account. This public/...
JAL's user avatar
  • 605
11 votes
Accepted

How can I determine if a piece of code is an encryption algorithm?

TL;DR: What we have here is probably not an encryption algorithm, it is more likely a decompression loop, by the look of it. It simply does not do anything that could be considered even remotely ...
NirIzr's user avatar
  • 11.8k
11 votes
Accepted

Decrypting IPA Binary on OS X

Currently you can't decrypt iOS apps without a device. The encryption keys are ultimately protected by an unknown key which is burned into the processor and cannot be extracted using software, that's ...
Igor Skochinsky's user avatar
  • 36.5k
9 votes

Question about Keeloq - A car remote control standard

To create a full duplicate, able to generate valid transmission packets you'll need the following information: Serial Number Button press mapping 32 bit of KeeLoq encrypted data See attached Figure ...
NirIzr's user avatar
  • 11.8k
8 votes

Reverse Engineering a Firmware. Someone can help me?

Finding: NGA_FW_CURRENT.BIN is a compressed Videx microchip firmware image file. Preliminary Remarks There is conflicting background information given in the comments about the file alleged to be ...
julian's user avatar
  • 7,108
7 votes

How to decrypt encrypted script files for a game?

There are two noteworthy communities dedicated to reversing file formats with video games: XeNTaX and ZenHAX Both of them have their own respective applications used for creating scripts that unpack ...
dsasmblr's user avatar
  • 2,234
7 votes
Accepted

How to decompile an exe file?

I have been wondering, if every program is based on machine code, can we not decompile a program until it hits machine code and make it up to real programming languages? This question is based on a ...
julian's user avatar
  • 7,108
7 votes

Finding AES Key in binary using Ghidra and FindCrypt

FindCrypt is not supposed to find your key, it's supposed to find fixed, known constants associated with well-known cryptographic algorithms. You can see the byte patterns it's looking for in its ...
Rolf Rolles's user avatar
  • 9,198
6 votes
Accepted

Decrypt the config file of ZTE F660 v9

Download script and config file Install zcu from https://github.com/mkst/zte-config-utility KEY = SERIAL + MAC: CF28772Bf438d406f608 from paramtag IV = DefAESCBCIV: ZTE%FN$GponNJ025 from /etc/...
xax's user avatar
  • 186
6 votes

i need software to decode this subtitle xml file, anyone know what it encodes with?

It's AES encrypted, but fortunately it's pretty trivial to see what's going on in the JavaScript file responsible for decoding (https://www.gohitv.com/series/js/hiplayer.min.js) by using browser ...
user7290573's user avatar
5 votes
Accepted

Having keys and binary, how do I reverse/decrypt a stream encryption?

Good news, You're lucky! What you're facing in front of you is a stream cipher. Why is that good? because the way stream ciphers are built makes them extremely easy to reverse - the decryption and ...
NirIzr's user avatar
  • 11.8k
5 votes

Animal Crossing: Pocket Camp .zdat File

The file does not appear to be obfuscated or encrypted in any way. The header appears to be trivial. I have included a description of the header for the .zdata you posted. The .unity3d files contained ...
TkTech's user avatar
  • 326
5 votes
Accepted

Unknown game file decompress

it seems to be compressed in some way because you can read some plain text there This statement is contradictory. If the binary were compressed or encrypted in its entirety there would not be any ...
julian's user avatar
  • 7,108
5 votes
Accepted

Stuck on XOR decryption of firmware

Well thanks to @IgorSkochinsky's suggestion, I found a disassembler for the Blackfin architecture in the pf0camino/cross-bfin-elf Docker image. Being in Docker meant it was easy to run and I didn't ...
Malvineous's user avatar
5 votes
Accepted

McDonald's receipt codes

As suggested in a comment, the final character is indeed a check digit. It appears to be calculated using the Luhn algorithm with 25 as the base instead of 10. Using the code in photo as an example: ...
user7290573's user avatar
4 votes

Extract decrypted Assembly-CSharp.dll from APK via IDA

I think the solution is a very simple one, with one small tweak. To decrypt the file, XOR the encrypted data with the bytes 0xFCC6DC7FDCC7DFE0 and you will get the unencrypted file. You can see this ...
David's user avatar
  • 501
4 votes

Decrypt / Decode / Decompress Proprietary File

I took a look at the empty template file that you provided. The file has a very high entropy which indicates that it's probably encrypted and not compressed. The header in the file could be a lot of ...
Gogeta70's user avatar
  • 171
4 votes

Unknown CRC calculation

MED17 functional description docs will help with overview of the EEP handler, but not the checksum routine. Usually it is best to go through the front door with coding tools rather than try to change ...
John Banks's user avatar
4 votes

how to find the encryption algorithm?

First, I have to say several things don't quite add up in the decompilation, and I often find it easier to understand disassembly than decompilation Let's start with the function doing most of the ...
NirIzr's user avatar
  • 11.8k
4 votes
Accepted

how to find the encryption algorithm?

All the credit for this this answer should go to the @NirIzr and @Avery3R. Here is a python script that implements the xoring mentioned by these kind people: import urllib import binascii data = "%...
w s's user avatar
  • 8,448
4 votes

Decrypting SQLite Database with key

There exists an official encryption addon for SQLite but from your description it sounds more like the data is simply stored encrypted in the blobs and the application decrypts it internally before ...
Igor Skochinsky's user avatar
  • 36.5k
4 votes
Accepted

Reverse engineering checksum - LG 485 a/c protocol

did not check the second set but your first set appears to be xorred by 0x55 0x55 ^ 0x18 == 0x4d (8 bit checksum ) edit ok my guess was right here is a python script that prints the chksum ...
blabb's user avatar
  • 16.3k
4 votes
Accepted

Help reverse decrypt function (decode -> encode)

For a = b ^ c Since the XOR operation is trivial to reverse when any 2 values in a, b, c are known, this will only require you to just reverse the order in which operations were done. I had to do ...
sudhackar's user avatar
  • 2,639
4 votes
Accepted

Intercept zip decryption key or files from an application

I'm writing this answer under the assumption the OP is within his legal rights to share the binaries. First of, I read up on password protected zip files. Apparently that is not part of the ZIP ...
Johann Aydinbas's user avatar
4 votes
Accepted

Reverse Engineering Temperatures (RS485 Bus)

I would guess that this is raw (unencoded) data and every row is consisted of two 16 bit integers stored in little-endian order. This means that temperature = (float)(b[3] << 8 + b[2]) / 10; ...
Anton Angelov's user avatar
4 votes
Accepted

Decoding Hex Data

The data are floating point encoded on 32 bits Little_endian byte 0 to 3: 00 00 00 00 = 0 channel number byte 4 to 7: 1f 85 a3 41 = 0x41a3851f = 20.4400005341 etc .. https://www.h-schmidt.net/...
Gordon Freeman's user avatar
3 votes

Decrypting assets (json/png/lua)

There are a few things you can still try, like running signsrch over the binary to see if it has any encryption algorithm signatures. Also, gzipping these files increases their size: gbl@roran:~/...
Guntram Blohm's user avatar
3 votes
Accepted

Extract text data from a compressed/encrypted .DAT file

These files are definitely not compressed. behavior_trees.dat is a binary file which is not encrypted and not compressed, just binary. Encryption, as far as I can see, looks like substitution cipher ...
w s's user avatar
  • 8,448
3 votes

Unknown CRC calculation

A9 68 01 00 FF 7F 00 80 FF 7F 00 80 FF 7F 00 80 FF 7F 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ...
cristiano sobral's user avatar
3 votes

Reverse engineer CAN-Bus checksum

As can be demonstrated by this page: CRC width: CRC-8 CRC parametrization: Predefined, CRC8_SAE_J1850 (Polynomial: 0x1d, Initial value: 0xff, Final xor: 0xff) CRC Input Data: Bytes, D1-D7
booto's user avatar
  • 931

Only top scored, non community-wiki answers of a minimum length are eligible