Re: [Tails-dev] Randomize full MAC address feature option in…

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Author: Ethan Krasner
Date:  
To: tails-dev@boum.org
Subject: Re: [Tails-dev] Randomize full MAC address feature option in welcome screen
>phone oui vendors resources to form oui list:

It would make more sense for full mac randomization to copy how android does it wouldn't it?

https://source.android.com/docs/core/connect/wifi-mac-randomization-behavior

>The MAC randomization feature randomizes the address by setting the locally administered bit to 1, and the unicast bit to 0. The other 46 bits are randomized.


https://en.wikipedia.org/wiki/File:MAC-48_Address.svg

So to implement that like the Android feature does:

0X:00:00:00:00:00

^

X would have to be 26ae

reasoning is XX:00:00:00:00:00 would have to equal an 8 digit binary ending in 10

xxxxxx10

^ determines the locally administered bit which has to be 1

^ determines the unicast which has to be 0

https://richardatkin.com/post/2022/01/14/MAC-Address-Randomisation.html

If you use this calculator u can see that 26ae are the only possible outcomes for this bit to end in 10

0X:00:00:00:00:00

^ the first part can equal anything between 0-9 and a-f as it doesn’t change the binary ending in 10

X = 2 or 6 or a or e [26ae]

https://www.compscilib.com/calculate/mac-address-to-binary?

The first part could be anything [0-9a-f] but the the second part would have to be [26ae] then the rest (10) randomized.

[0-9a-f][26ae]:00:00:00:00:00

echo $(/usr/bin/tr -dc a-f0-9 </dev/urandom | /usr/bin/head -c 1)$(/usr/bin/tr -dc 26ae </dev/urandom | /usr/bin/head -c 1)$(/usr/bin/r -dc a-f0-9 </dev/urandom | /usr/bin/head -c 10) | /bin/sed 's/../:&/2g'

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