Can a system admin force encryption on for a whole system at will? Is this possible? (P25 Phase II)

[ElroyJetson]

A simple question. Can a system administrator, running a P25 Phase II system, force systemwide encryption on or off at will,
or force it for select talkgroups?

Imagine a system where they have encryption features in every radio but have not chosen to implement encryption today.
Then some incident occurs which causes a security panic. And the system administrator orders encryption on for all LEO talkgroups,
or the whole system. Presume that any unkeyed radios would be keyed via OTAR, even if that requires OTAR rekeying of the ENTIRE
system, every radio....and that brings up the secondary question, can entire groups of radio be OTAR rekeyed at once?

 

[KevinC]

Speaking for MSI core. I guess you could go into PM and set every TG to secure only.

 

[GTR8000]

Clear/secure is determined at the talkgroup level. Despite the common expression used by some, there is no "switch" to flip to turn encryption on/off for an entire P25 system at once. Phase I, Phase II...that distinction makes absolutely no difference. P25 trunking is P25 trunking at the fundamental level, and the control channel (save for a few newer L3Harris systems) is FDMA anyway.

If a talkgroup is provisioned for secure operation only, subscribers trying to transmit in the clear will get bonked.

Radios cannot be initially keyed or rekeyed with a TEK over the air without the proper KEK already being present in the subscriber. Key Encryption Key (KEK) vs Traffic Encryption Key (TEK). Security measure to prevent any old radio from receiving a TEK that it's not authorized for.

Oh and the subscribers have to be programmed to know whether to transmit in the clear or secure on a per-talkgroup basis. You can program them for "Select" which allows for a switch to go between clear and secure, but if the talkgroups are in the codeplug as clear TX, strapping the talkgroups themselves to secure in the system is only going to cause them to be unusable without a massive reprogramming.

Sure, you could push new codeplugs through over-the-air reprogramming if the system has that feature, but again, lots of things have to be in place and it is a very slow process as P25 data is quite bandwidth limited.

Your scenario is pretty unlikely.

 

[ElroyJetson]

Thanks for the information. Much appreciated. I kind of figured it'd be something like that.

 

[mrsvensven]

The "R" in OTAR stands for Re-Key. It's for changing the keys in radios that already have keys, not for unkeyed radios. It's still possible that many radios do already have keys and are loaded into the OTAR system even if they aren't actually using any keys.

As others mentioned, its not a quick or simple "throw a switch", but not impossible. Assuming the radios do already have keys loaded, the administrator would start by setting the desired talkgroups to support either clear or encrypted voice. Next they would OTAP (over the air program) each radio to transmit in encrypted mode on the desired talkgroups. This is the step that is going to take a while (days, weeks, or months depending on the number of radios). As radios are reprogrammed you would start to notice more encrypted traffic and less unencrypted. Eventually the administrator would set the talkgroups to only allow encrypted calls.

 

[ElroyJetson]

I'd guess that the process would happen more quickly if the radios had LTE functionality. But at a stiff premium per radio. (1500 or so in the case of Harris radios.)

Seems that the most practical way to switch over from clear to encrypted is to use the designated switch on every radio, and tell everybody to move the switch to the encrypted position.

 

[GTR8000]

Or just provision the talkgroup(s) in secure mode from the get go? 🤷‍♂️

 

[TampaTyron]

The way we do large switches from an old configuration to a new configuration is to have old zones in the radio and then have duplicate zones with the new settings in them added to the radios. Then on the specific day, the users change zones in the radio from the old zones to the new zones containing the changes. The old zones are deleted after the change via cable, over the air, or via wifi. TT

 

[Ensnared]

Waco law enforcement used to have two separate trunked systems prior to HOTRRS. Routine law enforcement was on MOT. However, the administration and drug enforcement talk groups were using TxWarn digital. TxWarn used to have a site near Waco.

I once heard two federal agents discussing how to activate and deactivate encryption at a repeater level. I also heard them say it was a bit difficult to do.

I know this does not involve an administrator, but I thought it would be semi-related.

 

[KevinC]

Waco law enforcement used to have two separate trunked systems prior to HOTRRS. Routine law enforcement was on MOT. However, the administration and drug enforcement talk groups were using TxWarn digital. TxWarn used to have a site near Waco.

I once heard two federal agents discussing how to activate and deactivate encryption at a repeater level. I also heard them say it was a bit difficult to do.

I know this does not involve an administrator, but I thought it would be semi-related.

If it's a P25 repeater it doesn't know or care if it's clear or encrypted.

 

[hp8920]

If it's a P25 repeater it doesn't know or care if it's clear or encrypted.

That's implementation dependent. There's no reason a repeater or trunked system couldn't be made to look at the traffic its passing and drop any calls that aren't configured the way it wants.

One could also design a system to encrypt/decrypt traffic as necessary. This happens regularly in those interoperability/tactical repeater boxes.

 

[KevinC]

That's implementation dependent. There's no reason a repeater or trunked system couldn't be made to look at the traffic its passing and drop any calls that aren't configured the way it wants.

One could also design a system to encrypt/decrypt traffic as necessary. This happens regularly in those interoperability/tactical repeater boxes.

Which repeaters can encrypt traffic?

 

[GTR8000]

CSS doesn't even have any parameters related to clear/secure operation for the GTR...it's pass through, repeater doesn't care, as long as the NAC it's expecting matches.

 

[hp8920]

Which repeaters can encrypt traffic?

Tactical repeater boxes that are two subscriber units back-to-back. See the BK RDPR and the Thales tactical repeater box. Also consider things like consoles, phone patches, automated dispatch audio, recording systems and IP data. Somewhere in the network, something is doing encryption and decryption.

Nothing in the P25 protocol itself requires encryption be maintained end-to-end. Specifically, P25 has traffic encryption but no authentication. Transmission are one-way: the radio has no idea or care what the repeater or system is doing to the data or where it came from, whether it's being decrypted or encrypted, converted to analog, bridged to LTE devices, etc.

These are limitations of slow-moving vendors and slow-moving government spec processes.

 

[KevinC]

Tactical repeater boxes that are two subscriber units back-to-back. See the BK RDPR and the Thales tactical repeater box. Also consider things like consoles, phone patches, automated dispatch audio, recording systems and IP data. Somewhere in the network, something is doing encryption and decryption.

Nothing in the P25 protocol itself requires encryption be maintained end-to-end. Specifically, P25 has traffic encryption but no authentication. Transmission are one-way: the radio has no idea or care what the repeater or system is doing to the data or where it came from, whether it's being decrypted or encrypted, converted to analog, bridged to LTE devices, etc.

These are limitations of slow-moving vendors and slow-moving government spec processes.

Ok.

 

[mrsvensven]

If it's a P25 repeater it doesn't know or care if it's clear or encrypted.

This feature has been requested by some large public safety agencies and is in development, if not already being tested.

 

[RFI-EMI-GUY]

A simple question. Can a system administrator, running a P25 Phase II system, force systemwide encryption on or off at will,
or force it for select talkgroups?

Imagine a system where they have encryption features in every radio but have not chosen to implement encryption today.
Then some incident occurs which causes a security panic. And the system administrator orders encryption on for all LEO talkgroups,
or the whole system. Presume that any unkeyed radios would be keyed via OTAR, even if that requires OTAR rekeying of the ENTIRE
system, every radio....and that brings up the secondary question, can entire groups of radio be OTAR rekeyed at once?

1) All radios could already have software encryption and key variable loaded which is difficult to manage and is usually done when commissioned.
2) Consoles require secure DIU capability.
3) Radios can be individually loaded with key variables using a Key Variable Loader which means touching all radios a few minutes at a time. Radios require Hardware Encryption and a secure Algorithm.
4) Traditionally keys are loaded OTAR with a key management facility optional software and hardware which is pricey for some agencies to consider. This can have the effect of OTAR the entire fleet, though it may take hours in the first instance and requires all radios to have hardware encryption, a secure Algorithm and OTAR feature. See also Post #3 GTR's details on shadow keys (KEK).
5) Assuming any or all of the above. The administrator could have all users switch to a secure talkgroup.

 

[RFI-EMI-GUY]

This feature has been requested by some large public safety agencies and is in development, if not already being tested.

Are you talking about Link Level encryption?

 

[RFI-EMI-GUY]

Tactical repeater boxes that are two subscriber units back-to-back. See the BK RDPR and the Thales tactical repeater box. Also consider things like consoles, phone patches, automated dispatch audio, recording systems and IP data. Somewhere in the network, something is doing encryption and decryption.

Nothing in the P25 protocol itself requires encryption be maintained end-to-end. Specifically, P25 has traffic encryption but no authentication. Transmission are one-way: the radio has no idea or care what the repeater or system is doing to the data or where it came from, whether it's being decrypted or encrypted, converted to analog, bridged to LTE devices, etc.

These are limitations of slow-moving vendors and slow-moving government spec processes.

Yes. Even when Motorola bridges to LTE devices which are encrypted, it is separate encryption for the LTE and within the core at some point plain text audio/data are handed between the services. This means there is a physical location, the core, which requires special physical security precautions. As far as the LTE encryption, I would expect it will be proven to have other vulnerabilities like any other commercial protocol.

 

[KevinC]

I think this has run its course. Closing.