[Cryptography] Compression before encryption?
hbaker1 at pipeline.com
Thu Jan 15 14:56:13 EST 2015
At 04:22 AM 1/9/2015, Stephan Neuhaus wrote:
>So, does any one know what paper I might be referring to? Or is there any other hard evidence (not personal opinion, however well-informed, please) that compression before encryption does or does not help?
Sometimes forgotten about compression algorithms: if something is compressed, then at some point it gets uncompressed. If an attacker can send such a "compressed" message, then (s)he can send a _super-compressed_ message -- one which uncompresses into a super-sized message that will choke any buffer/memory allocation/swap partition/address space. Such a supercompressed message is a buffer overflow on steroids. Depending upon the compression algorithm, some uncompressed messages can be several exponentials larger than their compressed versions. Some programs are unprepared for this explosion of bits.
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