These past 2 weekends I explored some of the possibilities of using txtenna, @gotenna and @SamouraiWallet for censorship resistance. Here is a thread on my findings
The two hostile environments I wanted to test- could txtenna be a solution in a prison or simmilar situation where communication is denied and could it be a useful tool for IP obfuscation/bypassing ISPs or Cell Network providers denying access to the bitcoin network
First- using txtenna as a tool for bypassing hostile providers. Potential use cases- avoiding tying your identity to bitcoin use or a particular address, denying attempts for chain analysis to link transactions to IP addresses addresses coindesk.com/chainalysis-ce…
My hypothetical scenario for this experiment - you are a bitcoin user who wants to send a transaction and avoid linking IP, MAC address or other identifiers that might connect it to a location or device. This could be achieved by creating a covert stationary relay point
For my first experiment I used an office space that I have access to and know the wifi password for. My other equipment was 2 $40 dollar android smartphones and 2x gotennas.
One phone runs the txtenna app and is connected to the buildings wifi network and a gotenna mesh. In the hypothetical scenario they are then conceiled somewhere on the building without the knowledge of the occupants. 
This in effect provides an open wifi access point for bitcoin transactions to anyone with a gotenna. A txtenna user who wishes to conceil their identity can then broadcast from potentially kilometeres away. Much greater distance and an extra degree of anonymity than via open wifi
I tested several transactions from around 500 meters away and had no issues despite being behind several walls or being conceiled inside them. Longer distances may have been possible but I did not try from further out. Gotenna gives the range in dense urban environments as 0.8km
For the second scenario I concealed the phone&gotenna inside a sock and ziplock bag. I then hid it in a bush within wifi range of a cafe who's wifi I had the password for. Initially I had problems getting results over 200m distance here.
I tried placing it in the tree and was able to get much better range. Seems that elevation helps with reception to some extent, or there was more interferrance at ground level. Successful transaction sent from a side street 900m away
These setups are not meant to be a demonstration of ideal fieldcraft & I'm sure there are counterpoints to its anonymity advantages. My hope here is to just to show how it could be used where internet access was possible but linking your devices or address to bitcoin was an issue
Next I wanted to see if txtenna was able to be used in a prison type environment where an alternative broadcast method like gotenna might be useful.
As I'm no longer able to get access to an actual cellblock (used to run one) I went to a series of disused military tunnels at north head for an approximation. These are underground & I'm able to put around 6 concrete walls at around 30 meters from the outside world in the way
I travelled inside untill I found a spot deep enough to block cellphone reception and then tried two transactions to my girlfriend on the outside. The first around 30 meters from the entrance and the second at the bottom of the mountain 200m away. Both sucessful.
I didn't try further out but it seems that layers of concrete and conditions untenable to cell networks are still ok for transmissions of a few hundred meters at least
Issues to be aware of-
1)one of the phones would not relay transactions while in sleep mode(screenlocked). Speaking to the Samourai guys this tied to how background processes are handled by different android versions. Lollipop seemed to work, marshmallow didnt.
1)one of the phones would not relay transactions while in sleep mode(screenlocked). Speaking to the Samourai guys this tied to how background processes are handled by different android versions. Lollipop seemed to work, marshmallow didnt.
2)Transactions are currently all routed through Samourais txtenna server. You can setup your own full node to be another access point by implementing this github repo. More publically available gateways would greatly help. Please join me in setting one up github.com/MuleTools/txTe…
