Code Trips & Tips

July 13, 2016

filecrypt – OpenSSL file encryption

overview Uses OpenSSL library to encrypt a file using a private/public key pair and a one-time secret. A full description of the process can be found here. configuration This uses a YAML file to describe the configuration; by default it assumes it is in /etc/filecrypt/conf.yml but its location can be specified using the -f flag. […]

June 26, 2016

Ardis Icons for Ubuntu desktop

A new (remastered) set of Ardis icons for Ubuntu desktop has recently been released, and they are a very pretty eye-candy (working really well with the Ambiance Crunchy theme – favor the green variant).

June 20, 2016

Git 2.9 has been released

This is the post on github and it shows a few useful and worthy features have been added. To install on Ubuntu 14.04 (and newer – possibly older too, but I haven’t tested it): sudo add-apt-repository ppa:git-core/ppa sudo apt-get update && sudo apt-get install git then you should see the newest version: $ git –version […]

June 19, 2016

Implementing A Merkle Tree in C++

Updated The code is now available on github: https://github.com/massenz/distlib. Introduction A Merkle Tree is a tree structure where the individual nodes’ hashes are computed and stored in the parent node, so that the hash stored in the root node is the only value that is required to later validate the contents of the tree (stored […]

May 29, 2016

Using Java 8 Optional and Functional interfaces to reduce boilerplate

The code presented here makes judicious use of Optionals, Functionals and the new Streaming interfaces. It’s all very awesome, and makes me wonder: Java, what took you so long?

May 15, 2016

HOW-TO Encrypt an archive file

Private/Public keypair Create the private key (one-off): openssl genrsa -out ~/.ssh/key.pem 2048 chmod 400 ~/.ssh/key.pem then extract the public key from it: openssl rsa -in ~/.ssh/key.pem -out ~/.ssh/key.pub -outform PEM -pubout NOTE The whole mechanism revolves around keeping the secret key key.pem, well, secret. This is the only critical part of the scheme. Everything else, […]

December 30, 2015

2015 in review

The WordPress.com stats helper monkeys prepared a 2015 annual report for this blog. Here’s an excerpt: The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 14,000 times in 2015. If it were a concert at Sydney Opera House, it would take about 5 sold-out performances for that many […]

December 26, 2015

How to add/change dates in Dropbox Camera Uploads timeline

Dropbox does not allow one to update the time/date for an uploaded picture via either the Web UI or the file tools; however, sometimes pics show up with either missing or incorrect dates in the Timeline. This is particularly jarring when that information could be very easily inferred from a couple of obvious places: the […]

December 21, 2015

Apache Mesos Anonymous Module Example

Remote Commands Execution I have just published the code for a Mesos module to enable operators to execute remotely arbitrary commands on Apache Mesos Agent/Master nodes, out-of-band from the normal task execution framework. This is a Mesos anonymous module which can be loaded using the enclosed modules.json descriptor; this module will add HTTP endpoints such that: we can monitor […]

December 12, 2015

OSX Preview “Waiting for Scanner…”

I recently ran into the dreaded “waiting for scanner” Mac Preview nonsense, where it essentially got stuck trying to scan a document. The fix was rather trivial once someone figured out what process to kill: $ ps -A|grep Image 601 … /System/Library/Image Capture/Support/icdd 705 … /System/Library/Image Capture/Support/Image Capture Extension.app/Contents/MacOS/Image Capture Extension … other […]