Tag Archives: encryption

Session Key support for Arduino with RFM69 wireless module

Felix Rusu from lowpowerlab.com has created an amazing library for the Arduino/ATMega platform to use cheap RFM69 wireless modules for wireless transmissions between nodes. For a list of all the features, see his readme: https://github.com/LowPowerLab/RFM69. His Moteino platform and library are perfect for roll-your-own home automation systems, which is just what I am doing!

However, in my mind the library was lacking one critical piece – being able to prevent wireless replay attacks. Using Felix’s library, RFM69 transmissions can be encrypted in hardware, but the receiving node had no way of verifying that the incoming transmission was from a legitimate node and should be processed. If an attacker captured a sensitive packet as it flew through the air, such as one to open your garage door, they could replay it at a time of their choosing and trick your home automation system into opening the door.

TomWS on the lowpowerlab forum and I did some brain storming and he proposed modifications to the base RFM69 library to virtualize some functions, allowing them to be overloaded to create ‘extensions’. Using his modification, I wrote a transmission session key extension.

More after the break…

Continue reading Session Key support for Arduino with RFM69 wireless module

ZFS on Linux with LUKS encrypted disks

To me, encryption of data at rest is just as important as encryption of data in transit. You never know if someone is going to break into your house and steal your computer. With so much personal information like financial data and pictures stored on the computer, it could be a major mess to recover from theft of your computer. (Of course, always keep an off-site backup for the really important stuff!)

I chose to migrate from the Solaris based OpenIndiana to Ubuntu. I had grown to love ZFS on OpenIndiana and didn’t want to lose its features. Luckily ZFS on Linux is now ready for prime-time! Unfortunately, ZFS on Linux is a few versions behind the official Oracle ZFS just like all other third part implementations of ZFS and does not support native encryption through the filesystem.

Continue reading ZFS on Linux with LUKS encrypted disks

SSL Client Authentication Step By Step

SSL’s primary function on the Internet is to facilitate encryption and trust that allows a web browser to validate the authenticity of a web site. However, SSL works the other way around too – client SSL certificates can be used to authenticate a client to the web server. Think SSH public/private key pairs, if that is familiar to you. In this blog post I will outline the steps to create a certificate authority certificate, sign a server certificate and install it in Apache, and create a client cert in a format used by web browsers.

Continue reading SSL Client Authentication Step By Step

SSLv2, why are you still around?


The SSLv2 protocol is an obsolete version of SSL that has been deprecated since 1996 2011 due to having several security flaws. Current standards (2016) are SSL 3.0 and TLS 1.0TLS1.0-1.2 with SSL being fully deprecated, however, a common finding in Nessus scans of web servers SSLv2 is still enabled. IIS through v7 and Apache with OpenSSL prior to v1.0 have it enabled by default.

Continue reading SSLv2, why are you still around?