@172pilot said in Good thing mysensors has non-repeatable encryption....:
@NeverDie Is a signing chip really necessary?
If the packets are truly encrypted, and the hack you're trying to foil is a simple replay attack, I would think that including a simple incrementing counter into the message would do it. All the receiver would have to do is to only accept decrypted messages with a counter number GREATER than the last one it received. This should be simple to do if the encryption/decryption is already considered relatively secure?
I think the answer is probably yes. Today. At this moment. At least for me and probably you. I mean, one could reasonably ask: why bother with having better security than my garage door opener? But as cracker tools become more prevalent, who knows what's coming next? It's not just us against juveniles and thugs, it's us against whatever weapons juveniles or thugs can download or buy ready-to-use from kickstarter (or aliexpress for cheap soon thereafter).
I'm planning to use this:
for rising with acetone
I plan on using this:
for rinsing with IPA.
I'm sharing the info because it's not always easy to find spray bottles with the right kind of chemical resistance. From what I've read, the usual advice for mechanical sprayers is to empty the container immediately after use because even with Viton seals and gaskets, very often "resistant" does not equate to "unaffected." For instance, LDPE ziplock bags may be able to withstand acetone for a while, but eventually the acetone will break through.
Likewise, I used to think that nitrile gloves were fairly resistant to most chemicals, but then I noticed that acetone passed through them quite quickly. Likewise, nitrile gloves would be a poor choice for handling methyl alcohol. According to this handy chart, the best type of glove for both acetone and methyl alcohol (as well as IPA) are butyl gloves: https://www.augusta.edu/services/ehs/chemsafe/PDF files/gloveselechart.pdf
As it happens, I picked up a pair just recently as PPE for use with, before, or after an ultrasonic PCB cleaning. However, last week I visited one of the big box hardware stores and their entire inventory of chemical resistant gloves was wiped out, so be sure to plan ahead.
Chapin International 10027 48-Ounce Industrial Acetone and Acetone Dye Hand Sprayer (1 Sprayer/Package), White, Full Size
Wash Bottle for Acetone, 500ml - Labeled with Color Coded Chemical & Safety Information (2 Color) - Wide Mouth, Self Venting, Low Density Polyethylene - Eisco Labs
LiBa Spray Bottles (4 Pack,16 Oz), Refillable Empty Spray Bottle for Cleaning, Essential Oils, Hair, Plants, Adjustable Nozzle for Squirt and Mist, Bleach/Vinegar/BBQ/Rubbing Alcohol Safe
$11.99 ($11.99 / Count)
Karter Scientific 210P3 Safety Wash Bottle, Narrow Mouth, 500 mL Capacity, Polypropylene/Plastic
As promised, what I found so far: the following dockerfile yeilds a usable cross-compile environment, provided you use it with a Makefile.
RUN apt-get update \
&& apt-get install --yes \
RUN git clone https://github.com/raspberrypi/tools
RUN git clone https://gist.github.com/3873805.git /build
CMD ["/usr/bin/make", "CC=/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-gcc"
# Seems I need a real makefile for the above to work.
For cross compiling mysensors to work, hoever, you also need to properly seed the variable in configure, for it to work correctly. This is where I left off.
I found a good "once and done" lubricant for my CNC called Krytox. It's made by Dupont, is non-toxic, never dries out, and is non-reactive with just about everything. It is more or less liquid teflon (PTFE). It comes in a wide spectrum of different viscosities. I'm using GPL105, but I think for a CNC one could argue for using a version that's a least slightly more viscous (i.e. GPL106 or higher).
There also exists grease versions of Krytox, so perhaps (?) that would be even better. In general, for any given lubricant, how does one decide what the right viscosity is to use?