23 questions
1
vote
1
answer
38
views
How to decompress raw PKZIP data without zip header in python?
I want to to decompress raw data from a file in an exotic format, but I know that the compression method is the same that is used in a ZIP file (PKZIP).
In the file the PK\03\04 signature is missing. ...
- 6,677
3
votes
1
answer
81
views
What is LENGTHS CODE OVER error and why am i getting this?
I am working on an improved program that attempts to recover PKZIP keys with intention of CUDA support, So I integrated a decompression algorithm from infgen to decompress an array of bytes instead of ...
- 129
0
votes
0
answers
19
views
What is the correct way of initializing keys in PKWARE encryption?
According to APPNOTE Chapter 6.1.4, the following is the correct way of initializing keys:
Key(0) <- 305419896
Key(1) <- 591751049
Key(2) <- 878082192
loop for i <- 0 to ...
- 129
0
votes
0
answers
176
views
how to decrypt stream based zipcrypto with password?
This is my test of Zipcrypto decryption with known password, It's my own exercise on what i have learned so far , but the code produces bytes different from expected plaintext and i can't figure out ...
- 129
0
votes
2
answers
77
views
what is the purpose of second argument in PKZIP CRC32()?
I am trying to find a way of improving the attack PKZIP encryption but some things aren't clear and for today its this one:
key0 = crc32 ( key0, pt );
This is the CRC32 i know as standard it takes ...
- 129
1
vote
1
answer
68
views
Why do i get more 256 false positive in PKZIP Decryption key verification?
I have been trying to brute force Key2 of ZipCrypto with first byte of CRC and last byte of encryption header to see how long would it take but i got more than 2000 valid keys.
From the APPNOTE, Key2 ...
- 129
0
votes
1
answer
291
views
Is the DEFLATE compression algorithm in ZIP and GZip formats based on LZ77 or LZSS?
Wikipedia states that the DEFLATE algorithm (used among others by the ZIP and the GZip compression formats, but also by the PNG image format) is based on the LZ77 algorithm :
Deflate is a lossless ...
- 381
1
vote
1
answer
322
views
What is the correct processing of deriving a key for PKZIP Encryption and Decryption?
The PKZIP stream cipher is a symmetric encryption scheme, where the secret key is required for both encryption and decryption. This key is used to produce a key stream of bytes for the one-time pad ...
- 129
1
vote
1
answer
1k
views
How to unzip Self Extracting Zip files in Azure Blob Storage?
I have a zip file(.Exe - Self-extracting zip file) that can be extracted using 7zip. As I want to automate the extraction process, I used the below C# code. It is working for the normal 7z files. But ...
- 1,245
0
votes
1
answer
730
views
Are the compressed bytes inside GZIP and PKZIP files compatible?
This question is a follow-up to "How are zlib, gzip and zip related? What do they have in common and how are they different?" The answers are very detailed but they never quite answer my ...
- 3,293
1
vote
2
answers
302
views
What's the Zip Strong Encryption Specification/SecureZip key derivation function?
In the (PK)ZIP specification at https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT, specifically in the Strong Encryption Specification (SES) section, there is a line on deriving a key from a ...
- 26.9k
0
votes
1
answer
3k
views
How to read a zip file written with pkzip in python?
I am trying to read a zip file in python that was written with pkzip:
import zipfile
fname = "myfile.zip"
unzipped = zipfile.ZipFile(fname, "r")
But get this error:
unzipped = zipfile.ZipFile(...
- 19.6k
3
votes
1
answer
1k
views
PowerBI .pbix DataMashup Compressed Directory
I am attempting to inspect a PowerBI .pbix file using python's zipfile library.
When unzipping the .pbix archive, I get the following structure:
DataMashup
DataModel
DiagramLayout
Metadata
Report
...
- 95
1
vote
2
answers
9k
views
How to decode an encoded zipfile using Python?
I have a base64 encoded zip file. I am able to convert that zip file and then extract its content using Windows commandline. I have been trying to do the same with Python, but unsuccessful. Could you ...
- 135
0
votes
2
answers
443
views
Mainframe pkunzip generates PEX013W Record(s) being truncated to lrecl=
I'm sending binary .gz files from Linux to z/OS via ftps. The file transfers seem to be fine, but when the mainframe folks pkunzip the file, they get a warning:
PEX013W Record(s) being truncated ...
- 3,311
3
votes
1
answer
5k
views
How to determine the encryption scheme of a zip file
I am looking at encrypted zip files (using PKzip format) and I don't understand how the encryption scheme is encoded in the binary format. In my research, I found this paper outlining the various ...
- 316
0
votes
1
answer
1k
views
How to decrypt secureZip encrypted files using Bouncy Castle and java?
We have to automatically send/receive zipped + encrypted hundreds of files per day to/from another company and they desire to use SecureZip by PKWARE at their side for this task.
On our side our ...
0
votes
1
answer
437
views
Why pkzip accept two passwords?
I'm trying to do this homework https://www.root-me.org/en/Challenges/Cryptanalysis/File-PKZIP When I write a function to crack it.
import subprocess from time import sleep
file = open('/home/begood/...
- 55
3
votes
1
answer
3k
views
How to unzip file zipped by PKZIP in mainframe by Java?
I am trying to write a program in Java to unzip files zipped by PKZIP tool in Mainframe. However, I have tried below 3 ways, none of them can solve my problem.
By exe.
I have tried to open it by ...
- 43
1
vote
0
answers
308
views
Bat file code for zipping Huge size files
We are trying to zip a folder(size ~100GB) on our client server through a bat file. This bat file is triggered via an autosys job. The folder contains files of .dat and a .523 format file
We have ...
- 11
1
vote
1
answer
3k
views
ICSharpCode.SharpZipLib Compression method not supported PKZIP
I have a problem with a zip-file created with the old PKZIP® Command Line for Windows version 4 from the year 2000.
I am using ICSharpCode.SharpZipLib to extract the file.
Windows has no problem to ...
- 817
20
votes
3
answers
32k
views
Insufficient memory in Windows command line
I created a batch file which copies a directory with xcopy for backup reasons. Then I use pkzip in order to zip the backup folder (and email it through a batch file which is working), but I am getting ...
- 311
1
vote
1
answer
3k
views
Is there any easy way to .zip up my source code with Visual Studio 2013?
When playing around creating new Visual Studio projects to try out various technologies, or a weekend project, I want an easy way to zip up my source and not worry about .pdb, obj/bin files, etc.
So ...
- 8,986