The compression tag has no wiki summary.
16
votes
1answer
346 views
Selective format-compliant JPEG encryption?
I am working towards building a format-compliant encryption system for pictures. The aim of it is to be able to obscure specific areas of a picture (i.e. faces, car license numbers...) while keeping ...
7
votes
1answer
5k views
What is safer: ZipCrypto or AES-256?
Like in title: which one of these encryption methods (ZipCrypto, AES-256) is more secure and why? I am asking about it because I'd like to know which should be preferred when compressing files with ...
6
votes
4answers
485 views
Is compressing data prior to encryption necessary to reduce plaintext redundancy?
As explained in William Stallings' Book, in PGP encryption is done after compression, since it reduces redundancy.
I couldn't relate encryption strength with redundancy. Could anyone explain more on ...
6
votes
2answers
479 views
Why is ciphertext from low entropy plaintext not compressible?
This comes following a discussion with a colleague.
My plaintext file plain consists of a about 100,000 lines of "all work and
no play...". It's size is: 2.2 MB.
...
6
votes
2answers
539 views
How much can we compress RSA public keys?
I am wondering to what degree we can define an RSA variant, with a security argument that it is as safe as regular RSA with a given modulus size $m$ (e.g. $m=2048$), in which the public key has a ...
2
votes
2answers
240 views
Attack XOR encryption of binary data compressed by zlib with known key length (very short key)
I am trying to break a packet format. The packet format simply packs several files into one big file. The file contents are plain. But the index data which contain offsets, file sizes and filenames ...
1
vote
1answer
134 views
Using compression to test encryption
Is the uncompressibility of encrypted data a necessary property for a good cryptographic algorithm?
To make a crude experiment, I encrypted an 8K file with all 'A' and then compressed both the ...
1
vote
2answers
187 views
Seeking special-use fingerprinting/hashing algorithm
For a project I wonder if there exists some kind of fixed-size checksumming/fingerprinting function in which based on this fingerprint given data block 1, it is easy to generate more data blocks that ...
-2
votes
3answers
303 views
Crypto-Compression Algorithms?
I was wondering, whether there exist such algorithms/enciphering procedures which both compress and encrypt the input data. That means, for starters, the output will be both smaller in size and ...
-2
votes
1answer
150 views
data structure of random / compressed data
can anybody explain to me what data structure results after data is compressed? I just try to find out the difference between random data and compressed data, the entropy of both is very high while ...
