KeyIDs in DSD+

Status
Not open for further replies.

BillLayton

Member
Joined
Mar 20, 2003
Messages
9
Location
Suitland, MD
Using DSD+ to decode encryption KeyIDs on Motorola and P25 systems, it typically displays a five-digit number.

But the key IDs are 1, 2, 3 or 4 digit.

How does the KeyID shown by DSD+ convert into the actual key id?

Tks!
 

SignalPatcher

Member
Joined
Jun 4, 2013
Messages
28
All of these is about Motorola MotoTRBO...

In case of Enhaced Privacy we get only KeyID. It can be from 1 to 255. You can see that in DSD+ v1.051 as KeyID=XXX. This type of encryption is marked with Alg=EP symbol.

Unfortunately, the key value is not displayed.

Basic Privacy doesn't need the key value. KeyID is enough but it is not shown in DSD+ v1.051. Unpublished version of this programme shows it. You can see that on this screen: http://forums.radioreference.com/voice-control-channel-decoding-software/295152-dsd-status.html (Alg=BP)
 

Radioman96p71

Member
Feed Provider
Joined
Jan 11, 2008
Messages
1,079
The KeyID in P25 systems is an identifier that tells other radios what key to use.

Most radios have 32 'slots' for keys, some have more, some less. When the radio receives a transmission on P25, a few things will be set. the AlgoID which says what encryption algorithm is being used (84 = AES256). And the KeyID. This way the radio knows which key to use. Otherwise I'm not sure the radio would be able to figure out which one to use as random guessing doesn't really work with modern encryption, that and it would take far too long for the radio to make a match.

TL;DR - The KeyID is simply a value that is passed from one radio to the rest that tells them which key it needs to use to decode the transmission.
 

BillLayton

Member
Joined
Mar 20, 2003
Messages
9
Location
Suitland, MD
Thank you for your insight.

Using DSD+ to decode P25 and Motorola II (trunked) signals, I receive data like this:

2015/01/21 02:32:43 Group call; TG=710 RID=1100617 KeyID=14094 AlgID=84 30s
2015/03/02 18:15:57 Group call; TG=851 RID=25247 KeyID=5973 AlgID=84 3s

A valid key ID on this system should be something like 1,2,3, 5, 6, 11, 14, 1401, etc. -- NOT 5973 or 14094.

Any idea how to convert the Key ID shown by DSD+ to the one used by the radio?

Also, where does one find a list of the algorithm IDs and types? I can't find a list.

Bill
 

cg

Member
Premium Subscriber
Joined
Dec 13, 2000
Messages
4,571
Location
Connecticut

gesucks

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
698
Location
Our Nation's capitol
DSD is most likely showing in Decimal. Key ID's are usually in hex. Also remember key ID does not = CKR or SLN. On most keys they are not the same
 

hrh17

Member
Joined
Mar 4, 2015
Messages
144
Location
.
I'll do some testing on a secure simplex and see what DSD+ brings the Keyid up as
 

hrh17

Member
Joined
Mar 4, 2015
Messages
144
Location
.
CKR=137

So I'm not sure where DSD+ got these keyID values from
 

Attachments

  • Keyid.png
    Keyid.png
    64 KB · Views: 2,371

DSheirer

Member
Premium Subscriber
Joined
Feb 15, 2010
Messages
572
Location
Fulton, NY
A valid key ID on this system should be something like 1,2,3, 5, 6, 11, 14, 1401, etc. -- NOT 5973 or 14094.
Bill

The LDU2 voice message encryption key ID field is 16 bits long ... you can have key id values in the range 0 - 65535

Denny
 

Radioman96p71

Member
Feed Provider
Joined
Jan 11, 2008
Messages
1,079
If you program the radio and check the box to "suppress key ID" it will usually show gibberish in the KID field. "Encrypt Call Parameters" is another one that is used a lot to mask the underlying details. I'm not sure how Moto works with the CKR/SLN key number but my Harris seems to be a direct relation. When I put Key ID 60 in the radio, it shows the same in DSD+.
 

hrh17

Member
Joined
Mar 4, 2015
Messages
144
Location
.
This was decoded correct. As stated above, you are looking at Hex vs decimal. Decimal 18 = Hex 12
I understand that part, but the Hex Keyid, is that from the keyloader that was used to load the radio?
 

mikewazowski

Forums Manager/Global DB Admin
Staff member
Forums Manager
Joined
Jun 26, 2001
Messages
13,457
Location
Oot and Aboot
Yes, that is the ID number of the key which is currently being used to encrypt communications. It resides in the keyloader and the radio.

If you're looking for the actual key itself, you're not going to get it.
 

hrh17

Member
Joined
Mar 4, 2015
Messages
144
Location
.
correct,unless you have the keyloader and can see the key being transferred over the wire using a logic analyzer.
 

BillLayton

Member
Joined
Mar 20, 2003
Messages
9
Location
Suitland, MD
Ok, thanks guys for the analysis.

So how does one convert the DSD+ keyID to the CKR ID? I assume the CKR is transmitted?

Is that even possible?

Bill
 

WayneH

Forums Veteran
Super Moderator
Joined
Dec 16, 2000
Messages
7,521
Location
Your master site
CKR=137

So I'm not sure where DSD+ got these keyID values from
For clarity's sake... CKR and Key ID are two totally different numbers. CKR won't go out of the air and is more for human reference when dealing with a radio that supports multi-key. KID is used by the receiving radio as a logical identifier to scan its list of keys, if more than one, for this KID because it quickly needs some way to distinguish one key from the other. So an agency can continually use the same CKR but as they OTAR this KID will change to something else.

For a current time period you can use the KID to fingerprint an agency along the lines of radio IDs. Being the ASTRO CAI radio ID can still be 1 the ID within the KMF will always be specific. If they OTAR then identification is back to square one.

For single key radios (i.e., M without multi-key) the CKR will be 1 and the KID 1.
 

BillLayton

Member
Joined
Mar 20, 2003
Messages
9
Location
Suitland, MD
How is a KID generated?

What formula is used to derive the KID?

It makes sense what you say. But even on simplex, every radio with the same encryption key transmits the same KID.

So is the KID created from the actual encryption key or some other formula? Encryption key plus ???
 

Radioman96p71

Member
Feed Provider
Joined
Jan 11, 2008
Messages
1,079
as stated above, the KID is programmed by the person that does the keyloading. It is simply there to organize all of the different keys in the radio. They can make it essentially any value they want as long as it is within the bounds of the software (I'm thinking the max KID in Harris is 4096 but I'd have to re-read the manual).

So the fact you are seeing the same KID in radios that have the same key is kinda a dead giveaway, they use the same KID so the radios know which key to use (even if its the only key in the radio).

Outside of the radio, the KID is useless trivial information and has nothing to do with the actual key value itself. It is essentially like overhearing two people talking and hearing one say "turn to page 14 and look a the 5th word", to that person that tells them what part to read next but to a third party the information isn't really useful at all. Other than to figure out that they are both reading from the same page in an unknown hypothetical book :)
 
Status
Not open for further replies.
Top