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1. pyrsync: A pure Python module for the rsync algorithm

   I quickly modified and packaged a pure Python implementation of the rsync algorithm today. It’s on Github and PyPi. It’s going to be used in the open-source, symmetrically-encrypted, bandwidth-efficient, cross-platform backup software that I’m writing. Because why, for fuck’s sake, would you trust *all the files* on your computer, plus your cryptographic scheme, and potentially, […]

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2. Automated, Bandwidth-Efficient, and Encrypted Backups

   I made a bash shell script to automate encrypted (remote or local) data backups with Duplicity. Duplicity uses asymmetric OpenPGP RSA keys to encrypt a tarballs of specified files to be backed up, and it also supports incremental backups. So, after making a full backup, it is more efficient do to the fact that it only saves changes made to files and not entirely new copies of files. Duplicity also supports versioning, i.e. you can say “give me File A from 3 days ago”.

   Duplicity is not efficient in it’s cryptographic design, as my friend Tom wisely pointed out, in that use of asymmetric cryptographic algorithms is heavily intensive upon processor resources, and it would be better to replace this feature with something more along the lines of the algorithms (e.g. AES, Serpent, and Twofish) and read/write speed testing features which TrueCrypt supports, for example.

   This script depends on both curl and a newer version of duplicity (which is not yet included in the standard repositories), so to install those dependencies in Debian-based distros do:

       $ sudo apt-add-repository ppa:duplicity-team/ppa
       $ sudo apt-get update
       $ sudo apt-get install duplicity curl
   

   Here’s version 0.1.2 of the backup script (or view it on Github here):

   #!/bin/bash
   # _____________________
   #| BACKUP[your].SH[it] |
   #|---------------------|
   #|v.0.1.2              |\                    ^    /^
   #|Written by           | \                  / \  // \
   #|Isis Lovecruft       |  \   |\___/|      /   \//  .\
   #|isis@patternsinthe   |   \  /O  O  \__  /    //  | \ \           *----*
   #|             void.net|     /     /  \/_/    //   |  \  \          \   |
   #|_____________________|     @___@`    \/_   //    |   \   \         \/\ \
   #                           0/0/|       \/_ //     |    \    \         \  \
   #                       0/0/0/0/|        \///      |     \     \       |  |
   #                    0/0/0/0/0/_|_ /   (  //       |      \     _\     |  /
   #                 0/0/0/0/0/0/`/,_ _ _/  ) ; -.    |    _ _\.-~       /   /
   #                             ,-}        _      *-.|.-~-.           .~    ~
   #            \     \__/        `/\      /                 ~-. _ .-~      /
   #             \____(oo)           *.   }            {                   /
   #             (    (--)          .----~-.\        \-`                 .~
   #             //__\\  \__ zomg!  ///.----..<        \             _ -~
   #            //    \\               ///-._ _ _ _ _ _ _{^ - - - - ~
   #
   # Backup script to automate SSH, SCP, SFTP, FTP, and IMAP backups through
   # Duplicity. Duplicity encrypts backup files through GPG before sending
   # files through protocol. This script runs a check on the available 
   # bandwidth, and only runs the backup when the bandwidth available is 
   # above a configurable threshhold.
   #
   # This is going to be rewritten using duplicati instead of duplicity in the
   # next major version release.
   
   SPEED=$(curl -w %{speed_download} -o /dev/null -s http://speedtest.sea01.softlayer.com/speedtest/speedtest/random1000x1000.jpg)
   INT=${SPEED/\.*}
   KBPS=$(echo $[INT / 1024])
   THRESHOLD="200"
   # Uncomment and set the following in order to not type your password.
   # This is incredibly insecure, as your password is then stored 
   # plaintext.
   #export PASSPHRASE='passphrase'
   
   # The $SPEED variable downloads a nice image of snow (into /dev/null so that
   # it isn't actually saved anywhere on disk). It also gives us a write-out 
   # (-w %{speed_download}) for the average available bandwidth (incoming) in
   # bytes per second.
   #
   # $INT turns the float $SPEED into an integer.
   #
   # $KBPS, as I'm sure you can surmise, turns the bytes per second into
   # kilobytes per second.
   #
   # $THRESHOLD can be changed to fit the user's preferences, and it defines
   # the minimum bandwidth which should be available for a duplicity backup to
   # take place.
   
   if [[ "$#" == "0" ]]; then
       echo ""
       echo "Usage: ./backup.sh   ... "
       echo ""
       echo "Backup locations can be locally stored on the same …

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