All Questions
12 questions
1
vote
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38
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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
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
1
answer
291
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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
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
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1
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3k
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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
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
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
3
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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
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