Questions tagged [encryption]

Process of encoding information such that decoding requires the knowledge of some secret (a key). This tag covers questions about obfuscated and encrypted programs, or tools, but higher level questions may get better answers on Cryptography Stack Exchange.

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18
votes
1answer
11k views

Analyzing encrypted Android apps (.asec)?

I've been trying to reverse engineer a paid android app that writes out some binary data so that I can export that data into other programs (it's a run/walk timer app, if anyone's curious, and I'm ...
12
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3answers
5k views

Totally unknown file analysis approaches

I guess this is the worst case. I have a file which was initially base64 encoded. This step was easy. But now all I can see is a bunch of rubbish. No structure, nearlly a maximum of entropy, no ...
11
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1answer
3k views

Howto clone Android RSA SecurID Software Token

At the moment I try to figure out how the RSA SecurID Software Token protects itself from getting cloned to another android device. The token I imported has no device binding enabled and I already ...
10
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2answers
2k views

Protect data stored in binary

Let's say I've some function(i.e. hash function), that generates value from input seed and some precomputed hash values, that are stored somewhere in binary. What are the possible approaches for: ...
10
votes
4answers
14k views

AirPlay Mirroring decryption (FairPlay)

I've been spending a good chunk of time looking at some 3rd party applications that were successful in "reproducing" (although I believe not necessarily by understanding the algorithm completely but ...
8
votes
2answers
10k views

ZTE encrypted backup config file

I was poking around in ZTE Speedport Entry 2i (CPE used mostly in Germany, Slovakia etc, probably custom made for Deutsche Telekom). It's possible to download backup of config from UI. I found out ...
8
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3answers
2k views

Reversing Apple Airport Express firmware updates

Apple provides firmware updates for their Airport products through 'Airport Utility'. Firmware files can be downloaded with the help of ~/Library/Application\ Support/Apple/AirPort/Firmware/version....
7
votes
1answer
246 views

Is there a way to find out which hash standard by studying the source code?

We have an embedded product, which we are carrying for several hardware iterations since more than 5 years ago. We have all the source code, most of it nicely documented. As the product is actively ...
7
votes
2answers
2k views

Virus uses a custom XOR encryption and need help possibly cracking it / Reversing EXE

As stated in my previous question i was infected by a encrypting virus that encrypts two 1024 byte blocks of any given file (First 1024, and last 1024) in some type of custom CFB XOR encryption. I ...
6
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4answers
7k views

Tracing to a function during debugging?

I am trying to find an encryption algorithm for a game client, but I need to find the actual register/stack in the client before I can decrypt/encrypt the packets correctly (on my emulated server side)...
6
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1answer
7k views

Reverse Engineering of a packet encryption function of a game

I am trying to make a game server emulator for a specific MMORPG (Perfect World). I know the basics of how the network of the game works and the structure for some packets, but they all are encrypted, ...
5
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2answers
201 views

Find out whether additional keys are being used when encrypting data

Assume I use a software to encrypt data. How would I go about to find out with IDA or other RCE tools as to whether there is more than one key used during the encryption? I am talking asymmetric ...
5
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1answer
2k views

Question about Keeloq - A car remote control standard

I have a question about Keeloq security. I have an original car remote controller (BFT Mitto 2) and I know this chip uses HCS301 with Keeloq implementation. I would like to clone this remote for my ...
5
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1answer
1k views

Obfuscated AES decryption assembly

I have recently been sifting my way through a whole load of assembly to try to identify how a program is decrypting some data. Thus far I have identified how the IV is extracted, that the IV is 16 ...
5
votes
2answers
3k views

Retrieving encryption/encoding logic from dll

I am trying to retrieve a decrypting/deconing logic from a program. Unfortunately I have virtually no experiencing in reverse engineering. I am building an alternative controller application for a ...
5
votes
1answer
155 views

How does IPA decryption works?

All IPAs being downloaded from AppStore gets encrypted on servers as part of FairPlay DRM. But decryption is accomplished on local device. As far as I know there is some hardware module which contains ...
5
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0answers
589 views

Reverse engineering an hydrometer's Bluetooth communication

This is a very specific question. I'm currently working on a project to create an android application capable of reading the values of an hydrometer via Bluetooth. By reading the datasheet, I suspect ...
4
votes
4answers
30k views

Decoding New Jersey Driver's License Codes

Driver's License numbers in New Jersey aren't random. They follow the format: Affff lllii mmyye, where A is the first letter of the person's last name, ffff is some mapping of the remaining letters of ...
4
votes
1answer
154 views

What can I do with a SSH certificate?

Doing an information security project at the moment. After gaining access to ftp drive, there was a file simply called 'hackme' inside. It contains what looks like to me a SSH certificate, but not ...
4
votes
1answer
2k views

Reversing encryption by analysing executable

I have a program that reads data from a file, parses/organizes it, and spits it out as an encrypted XML. The application can also take an encrypted XML and spit out the original file. My objective at ...
4
votes
2answers
2k views

TP-Link encrypted backup file TX-VG1530

I have been trying to wrap my head round this stuff so bear with me. I have a Tp-Link TX-VG1530. From the gui you can download the config file however the file is encrypted, I include a portion of ...
4
votes
1answer
2k views

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

I would like to ask if you have any idea or approach to reverse engineer a decryption algorithm to find the opposite encryption function. I do have all required keys and fields and of course the ...
4
votes
1answer
290 views

What does this Generate_Key_IV assembler routine?

I want to decompress some files, and found some information on how. Apparently they are encrypted with AES 128 in CFB mode, and sometimes compressed using ZLIB. Each file's key and IV is supposedly ...
4
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2answers
1k views

Identify password generation algorithm

I'm a newbie who just started own way through reverse engineering so I apologize if my question is not appropriate. Currently I'm going through different Crackme puzzles and now I'm stuck. I've spend ...
4
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2answers
72 views

Is there a way to confirm and decompress files that I suspect are compressed with a very early format of PKZIP?

I have a very large number of files (tens of thousands) who's binary all begins with 0x00 0x06. They do not open with 7-ZIP. I notice also that all Office files seem to share the same next 32 bytes. ...
4
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0answers
3k views

Well-known JSON obfuscator that puts the string “Salted12” in front of obfuscated files?

I have an application that pulls some JSON definition files from the internet. In former versions of the application, these files were genuine json files; now, in a later version, they seem to be ...
4
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0answers
780 views

Reverse Engineering XORed string

I am trying to reverse engineer some data received over serial port. The hardware sending the data consists of a gps, compass and a power monitoring unit (which sends information about the battery). ...
3
votes
1answer
426 views

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

I am trying to reverse engineer a malware, and came across a piece of code that I suspect is an encryption/decryption procedure, however I do not know for sure. I can recognize that it extracts its ...
3
votes
1answer
4k views

Finding the encryption key in a binary - IDA Pro and how an S-box might be represented in the binary

In practicing reading source code and analysing I've been looking at a program called aescrypt2_huawei which floats around the web and encrypts/decrypts the XML config file from Huawei routers like ...
3
votes
3answers
1k views

Reimplementing the x86 AESENC instruction in python

I'm having troubles implementing the AESENC x86 instruction in python. I'm reverse engineering the decryption of a indie video game. They use AES but they xor some generated data around and the key ...
3
votes
1answer
112 views

Help deciphering binary that creates 3 passwords

I found a binary on a device I've been working on, it's called genrandpass and the only user input is a public key (which is a .bin file) that's stored locally on the device. It also gathers some ...
3
votes
2answers
4k views

What key is being using to encrypt the key transport in this Zigbee capture?

I am working with a Zigbee system and I have been trying to grab the network key as it is exchanged during pairing. I wasn't having much luck with the combination of TI Packet Sniffer, Wireshark and ...
3
votes
1answer
498 views

Identify a decryption scheme

I'm trying to identify a decryption scheme used by some licencing mechanism. It took me some time to realize that this was encryption and this is some kind of follow up to this other question of mine :...
3
votes
1answer
141 views

String Encoding and Decoding Method

so I came across the following string encoding method in python. def encode(the_string): encoded_string = '' rotations = ord(the_string[-1]) + 5 for i in range(0, len(the_string)): ...
3
votes
1answer
392 views

Identifying an algorithm used to sign iCloud payload

I'm trying to decipher which algorithm was used to sign a specific chunk of data while reverse-engineering iCloud backups. Long story short: I'm trying to retrieve some old voicemails that I lost when ...
3
votes
0answers
708 views

Obtaining the decryption keys for Super Mario Run (Android/iOS Game)

Super Mario Run is a il2cpp Unity game. Most of its assets are downloaded in-game through http requests. I particularly want the OGG files of the music. I can see the list of their names comes from ...
3
votes
1answer
572 views

Reversal of unknown obfuscation or encryption with known plaintext

Introduction For academical reasons I am reversing a firmware for an embedded device. I have already created a perl script which is able to parse the firmware structure and extract files from it (its ...
2
votes
2answers
8k views

Steps for determining the hash algorithm used

I have 5 test users and they have the same password. I am testing an application which stores the password in the database in an encrypted format. I want learn which hash algorithm has been used on ...
2
votes
2answers
317 views

How can I identify how this string is being encoded so I can replicate it?

A friends company uses an old VB6 application to generate encoded strings to then use in their also old and out of date database system. They have the application running in standalone mode so I can ...
2
votes
2answers
202 views

Attack on wireless interconnection [duplicate]

Scenario: Two devices have wireless connect. ( like wi-fi ) Probably encrypted. ( like wi-fi's WPA2 ) Which instruments are best for discovering carrier frequency? How encrypted-text should be ...
2
votes
3answers
1k views

Declaring block as a string in IDA

I'm reverse engineering a binary that has very generic, standard xor+math encryption on every string. I've written IDAPython to find each one(they're used in a generic way) and decrypt them, then add ...
2
votes
1answer
6k views

How do Enigma, Themida and VMProtect compare to each other?

I'll be releasing a piece of software soon and I'm looking for good protectors. The three that came to my attention were: Enigma, Themida and VMProtect. I searched a lot online but I couldn't find ...
2
votes
2answers
2k views

How to get file back from generated sha256 checksum?

The title seems little crazy, but I think that it is possible. Just think about it. If you create text file like this: Hello world! You get this checksum: ...
2
votes
2answers
421 views

Emulation Project - GameGuard Protected Client

I'm not new to MMO Server Emulation, but I am new to working with a protected Client, and have very basic RCE skills. I would appreciate some direction, and maybe this won't be possible, given the ...
2
votes
1answer
124 views

How can I generate the recovery password on a legacy system (Original company is out of business) running on my local machine?

I'm attempting to use a legacy systems recovery feature that typically required calling/faxing a company that is no longer around. Basically, the system was designed to go into a recovery mode and ...
2
votes
1answer
3k views

Decrypting SQLite Database with key

I have a SQLite database that contains a dictionary (just words and definitions) that can be opened with free but proprietary software. To use with the software, it requires an 'unlock' key, which I ...
2
votes
1answer
1k views

Identify decompiled decryption algorithm

I'm trying to analyze a decryption algorithm I'm reverse engineering and am wondering if anyone would from looking at the logic be able to identify one of the standard/common ciphers people use. The ...
2
votes
2answers
246 views

Understanding a messengers protocol encryption

For my own personal curiosity and development (building a bit of code mimicking the protocol), I am trying to figure out what the communication protocol encryption is made out of in a particular chat ...
2
votes
1answer
682 views

Help me understand how to actually break an XOR/Vigenère cipher

My friend's server was recently hacked and I'm trying to decipher the malicious files I found in hopes of understanding the hack better. I can tell that they're using an XOR/Vigenère cipher and I've ...
2
votes
1answer
270 views

create pem from ecc signature bytes

I am researching an QNX ARM based car navigation and it seems this system has a backdoor that enables telnet access without password to the system if a challenge/response succeeds. When a file ...