[Cryptography] Russian "ERA" cryptophone fiasco

[Ondrej Mikle]

On 3/30/22 05:05, John Denker via cryptography wrote:
>> The lack of foresight involved in the introduction of the Russian
>> army’s new Era encrypted-communications system [...]. Supposedly
>> secure, it relies on 3G towers—which Russia destroyed when it
>> invaded Ukraine. Because the system is simply not working, Russian
>> officers have to communicate in open speech by cellphone, as gleeful
>> Ukrainian volunteers listen in. [3]
> 
> Uhhhh, why do cleartext cellphones work if the towers are down? At
> what point do we start to disbelieve what we are told about this? And
> isn't it a bit odd and a bit unwise for people to brag about such
> exploits before the war is over?

As far as I understood it, they needed 3G/4G protocols. Why anyone would design 
a military radio that depends on mobile towers is beyond me. Did they expect 
that they would carry their own towers that have fairly limited range? I don't 
know, couldn't find any information or had the actual phone in hands to know.

The cleartext intercept was AFAIK based on the fact that the Russian army did 
loot stores with SIM cards and use them in their phones, not using ERA, because 
ERA could not be used.

I also have no idea what protocols are supported by the still standing towers. 
2G had about 20 km range if you had clear visibility. We did test that when we 
were writing the old A5/1 cracker decade ago. Also, the mobile protocols are 
insane mess. Anyone interested in middle-endian? You will find that there.

Regards,
   OM