Category Archives: compression

A Real Time Data Compression Technique

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With more and more embedded systems being connected, sending state information from one machine to another has become more common. However, sending large packets of data around on the network can be bad both for bandwidth consumption and for power usage. Sure, if you are talking between two PCs connected with a gigabit LAN and powered from the wall, just shoot that 100 Kbyte packet across the network 10 times a second. But if you want to be more efficient, you may find this trick useful.

As a thought experiment, I’m going to posit a system that has a database …read more

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Stretching My Skills: How (and Why) I Made My Own Compression Sleeves

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Have you ever noticed how “one size fits all” often means “one size poorly fits all”? This became especially clear to me when I started using a compression sleeve on my arm. Like any hacker, this seemed like something I could fix, so I gave it a shot. Boy, did I learn a lot in the process.

A little over a year ago, I started dropping things. If I was holding something in my left hand, chances were good that it would suddenly be on the ground. This phenomenon was soon accompanied by pain and numbness, particularly after banging on …read more

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Mechanisms: Mechanical Seals

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On the face of it, keeping fluids contained seems like a simple job. Your fridge alone probably has a dozen or more trivial examples of liquids being successfully kept where they belong, whether it’s the plastic lid on last night’s leftovers or the top on the jug of milk. But deeper down in the bowels of the fridge, like inside the compressor or where the water line for the icemaker is attached, are more complex and interesting mechanisms for keeping fluids contained. That’s the job of seals, the next topic in our series on mechanisms.

Packing it In

One of …read more

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Selective Compression on BIG-IP

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BIG-IP provides Local Traffic Policies that simplify the way in which you can manage traffic associated with a virtual server. You can associate a BIG-IP local traffic policy to support selective compression for types of content that can benefit from compression, like HTML, XML, and CSS style sheets. These file types can realize performance improvements, […]

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How can I select a compression utility that is popular and secure enough

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In a previous posting on Which is a safe way to transfer a copy of a sensitive document?, I have received suggestions to compress and encrypt an attachment file using the options of utilities such as zip, rar, 7zip and suchlike.

Although the specifics are not important here, the manual page of zip alerted me that there is much more to it than choosing a compression utility and send. Very seriously, the page zip is cautious to the point of hinting that you are not getting any serious encryption (emphasis added)

-P password
–password password

Use password to encrypt zipfile entries (if any). THIS IS INSECURE! Many multi-user
operating systems provide ways for any user to see the current command line of any
other user; even on stand-alone systems there is always the threat of over-the-shoulder
peeking. Storing the plaintext password as part of a command line in an automated
script is even worse. Whenever possible, use the non-echoing, interactive prompt to
enter passwords. (And where security is truly important, use strong encryption such as
Pretty Good Privacy instead of the relatively weak standard encryption provided by zip‐
file utilities.)

Forewarned is forearmed. I have browsed/scanned several postings in this community such as

It is a lot of (interesting, well-presented) information, and the problem has many dimensions: compression utility, encryption algorithms, archive handler, perhaps many more.
The drawback there is that I am a lay, moderately computer-savvy user, who faces the problem of choosing a compression utility that should have the following features:

  • be OS-agnostic. I am principally a Linux user, but I cannot afford making assumptions on which OS the mail recipient is using — it’ll probably be a Windows family member, although not necessarily — I might wish to dual-boot on Windows one-off to bridge this gap;
  • produce an encrypted file that is archive-handler agnostic. Likewise, I don’t know which archive handler the recipient is using — it’ll probably be a Windows Explorer of sorts, but not necessarily;
  • provide serious security; any perfunctory scrambling or placebo is obviously a waste of time;
  • produce a file that is relatively handy to decompress and decrypt; I cannot make assumptions on how lay and computer-savvy the recipient is. He/she might even be someone for whom installing a new program can be taxing, assuming that his/her employer permits this in the first place.

Apparently, I need some guideline to navigate this problem and choose what to do for an informed guess.

Is there any ‘self-aid’ wiki resource that you would recommend to find what one is heading for when using this or that utility? Any other suggestions ideas allaying these sorts of headache?

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