The code I have contributed to the Wireless Sensor Networks research project at TU München has been released for TinyOS under the GPLv3 open source license. It features the TinyIPFIX application layer protocol along with additional data aggregation features implemented by Benjamin Ertl.
Download TinyIPFIX Source
A short description of TinyIPFIX along with my related publications on the topic can be found in the research section of this homepage.
I have ported the large integer code of the amazing CyaSSL to TinyOS 2.x and written/ported some TinyOS wrappers for RSA and ECC. It was tested on 16-bit and 32-bit microcontroller platforms and should run on 8-bit platforms as well. It supports ECC key lengths from 112 bits to 521 bits and arbitrary RSA key lengths. The source is available under the GPLv2.
If you’re interested, performance figures can be found here. A short description of my related work on DTLS in wireless sensor networks can be found in the research section of this homepage.