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.

Filter by
Sorted by
Tagged with
1 vote
2 answers
899 views

identify packer compression or encryption algorithm

I do have an executable packed file. I want to detect compression or encryption algorithm dynamic and static ways separatly; of course without signature base way. How can I detect compression or ...
7 votes
1 answer
10k 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, ...
11 votes
2 answers
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: ...
  • 803
2 votes
3 answers
2k 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 ...
4 votes
1 answer
222 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 ...
user avatar
4 votes
2 answers
1k views

finding a RC4 Encryption function in obfuscated assembly code with no symbols

RC4 encryption is quite basic and its Pseudo random generation algorithm is given at Wikipedia When Looking for a hashing algorithm like MD5 or SHAx it is pretty simple to look for the Hashing ...
  • 658
2 votes
2 answers
594 views

SHA + Mersenne Twister

I'm trying to decrypt some audio files. At first I thought that they were encrypted using Blowfish, but apparently "SHA + Mersenne Twister used for generate key and decrypt". What exactly does this ...
  • 173
3 votes
1 answer
596 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 :...
  • 439
4 votes
0 answers
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 ...
1 vote
0 answers
266 views

How to remove SimplePack signature so it won't be detected by AVs

I've tried SimplePack, which is an open-source file packer for windows, now, for some reasons, when I check via online virus-checkers, lots of alerts are being popped saying the file is crypted using ...
2 votes
1 answer
338 views

How to retrieve stored information, NAND filesystem with VB.Net

I have been reading and reading about NAND and NOR flash.I am wantina (Usualy 512 bytes) to access some stored information in a nand.bin file but cannot for the life of me figure out what I need to do ...
  • 23
10 votes
4 answers
17k 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 ...
0 votes
1 answer
92 views

Question about interaction between some message-functions()

i have found the following code sequence in a sample which I try to analyze: .... push offset LibFileName ; "KERNEL32.DLL" call LoadLibraryA mov esi, eax test esi, esi jz short loc_40EDF2 lea edx, ...
  • 1,501
2 votes
1 answer
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 ...
5 votes
6 answers
58k 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 ...
3 votes
1 answer
425 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 ...
  • 31
0 votes
0 answers
945 views

How does iOS hash and salt passwords on its secondary-storage?

I bought a used iPhone from someone, but I accidentally got a lock screen on the phone and can't figure out what the passcode is. Long story short, how does iOS hash the passcodes for entry, what kind ...
2 votes
2 answers
274 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
0 answers
3k views

Unpacking and disassembling mach-o binary

I am trying to reverse an OSX mach-o binary, Disassembling gives me a bullshit, seems its encrypted with some packer. I need to determine the encryption algorithm, and decrypt the binary. Load ...
  • 129
7 votes
2 answers
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 ...
1 vote
0 answers
660 views

How to decrypt this file?

I have to decrypt a file that is used by an app built using VB5. The file itself contains some data that is decrypted when the app is run and the decrypted data is text data that is displayed in a ...
6 votes
2 answers
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 ...
  • 161
9 votes
3 answers
3k 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....
  • 91
2 votes
3 answers
279 views

Facing encryption

I have an encrypted hex string: AA969CF9657F77C597C8EAFF1594D59374E4977F which I know corresponds to the plaintext: http://jogos.meo.pt/ I want to know if it is possible to find out what ...
5 votes
0 answers
848 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). ...
5 votes
1 answer
314 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 ...
  • 173
3 votes
2 answers
223 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
1 answer
2k views

Reverse Engineering an Encryption Algorithm

I have a program that has the ability to encrypt files and I want to be able to create a program that can read these files. I believe it uses a Blowfish encryption, but I'm not certain on that. How ...
14 votes
1 answer
4k 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 ...
13 votes
3 answers
8k 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 ...
  • 231
5 votes
2 answers
210 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 ...
  • 10.6k
3 votes
2 answers
15k 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 ...
  • 39
7 votes
4 answers
8k 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)...
  • 71
22 votes
1 answer
12k 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 ...
-3 votes
1 answer
218 views

Is it possible to get the encryption key when you have the plain text [closed]

i have a question about SHA256 I know that this algorytm was used to encrypt a text, wich i have, also i have the encrypted version of this text. My question is can i somehow get to the encryption key ...
  • 107

1 2 3
4