Batboard

After finding out that with 2 KVL's in different modes with a common LID/CKR being able to load a key, I have another question regarding encryption interoperability. Where is the difference and limitation in the variations of DES keys i.e DES OFB/DES XL, I know there are variations with XL regarding range. Can those 2 algos communicate with one another if the key is generated exactly the same? When you get into the different modes such as ASN or Astro 25 of the KVL, are there any limiting factors given the radios are programmed with PID and CKR enabled? I am just trying to wrap my head around all of this, because it is confusing sometimes. I know of course AES and DES won't talk, but I just don't know the variations of DES, DES-XL,DES-OFB and if they are compatible. I hope I am clear in what I am asking.

DES, DES-XL and DES-OFB do not play nicely with each other... OFB is for digital voice modes only (IBME/VSLEP) - cannot use OFB in analog voice mode.

DES has limited range compared to DES-XL. DES has significantly less range than clear voice; DES-XL has slightly lesser range compared to clear voice.

Most Securenet capable middle/upper tier radios, i.e. Sabers/Spectras, can enable/disable -XL function by mode, i.e. communicate on freq 1 in DES-XL on mode 1, communicate on freq 1 in DES on mode 2.

http://members.aol.com/batlabsdotcom/encryption.pdf

Randy Ran wrote:After finding out that with 2 KVL's in different modes with a common LID/CKR being able to load a key, I have another question regarding encryption interoperability. Where is the difference and limitation in the variations of DES keys i.e DES OFB/DES XL, I know there are variations with XL regarding range. Can those 2 algos communicate with one another if the key is generated exactly the same? When you get into the different modes such as ASN or Astro 25 of the KVL, are there any limiting factors given the radios are programmed with PID and CKR enabled? I am just trying to wrap my head around all of this, because it is confusing sometimes. I know of course AES and DES won't talk, but I just don't know the variations of DES, DES-XL,DES-OFB and if they are compatible. I hope I am clear in what I am asking.

Ok here is some more info, last night I configured 2 KVL's, one for DES-XL the other for DES-OFB, both with the same key, I loaded the key created from each kvl into 2 XTS-5000's, one with XL the other with OFB. They are able to talk fine. What is the main difference between XL and OFB, is there a difference that will change the actual algo? Programming wise on both radios the DES-XL TX default wasn't enabled, so it was default to OFB. How were 2 radios with seperate DES algos communicating?

How was your modulation set IMBE of analog?



CoM

A DES-XL loader keys a -XL and -OFB chip the same way (speaking of the DX loaders of course).

Depending on your programming, the XTS is seeing the key and algo, and decoding it properly. What should really help you (somewhat), is to read the CPS help files about proper code detect, PID/CKR, DES-XL default, et al.

DES-XL and DES-OFB will sound the same in the digital mode. Of course, -OFB will not work in the analog mode, as its a digital only mode of operation. The -OFB was written specifically for the digital mode of operation, but is still based on the same old DES standard.

I have had radios with DES-XL and ASTRO's with both algo's, and depending on how you set your options, you will hear both, or just one.

If your TX radio is -OFB only, and your RX radio is -XL only, they are not going to talk to each other (and vice versa).

My guess is that the XTS's have both hybrids installed. How have you verified what chip is in them? Most DES enabled XTS's have the DES-XL/OFB module installed. There were single algo chips produced, but seemed to be in the minority.

As far as the XTS-5000's go, the algo's are there, DES XL and OFB as well as AES. As far as PID/CKR, I know that it is just key management and doesn't designate anything to do with the actual algo used. In the programming of the radios, used DES-XL default is not enabled. This thread was started purely because I was curious in the variations of DES. I just wanted to know the working difference or algo difference between the different forms of encryption. From reading up, the answer to my main question is that the variations in the algos are in how they operate or in what mode analog or digital. Thanks for all the input.

Well, key management can affect which algo's are used, but for 99% of us here, it really doesn't matter.

Since both radios have the same secure hardware, and they way that use used the keyloader, it was the same key working on the same algo that was being tx'd and rx'd if I understand everything you did (remember, your not loading a -xl or -ofb key, your just loading a key...your programming can have a difference in what algo your using). In short, DES-XL, DVP-XL will work in analog and digital modes. AES, DES-OFB, ADP will only work in the digital mode.

The DES DX loader will load keys for DES-XL, OFB, etc
The DVP DX loader will load keys for DVP-XL

So if you had a DES-XL/DVP-XL module, each key would be unique to that type of encyption...so if you picked key 1 which is DES, it will xmit DES. If you selected key 2 for DVP, then you would be xmiting that. Its easy and complex at the same time.