Folk,
Lookin for the answer to these questions. Any input is much appreciated!
1. With the DES-XL Tx default unselected in each Trunking System, is DES-OFB then the algorithm used when the radios have the
dual-hybrid UCM with DES-XL/DES-OFB?
2. What is the cipher strength of DES-XL vs. DES-OFB? I believe DES-XL is a 56-bit cipher.
3. Which is more secure? DES-XL or DES-OFB? Why ?
4. Is there any degradation in performance using one over the other ?
5. What are the other PROS/CONS of using DES-XL vs. DES-OFB?
DES ENCRYPTION TEST
Moderator: Queue Moderator
...
Same encryption method, just DES-XL is for analog and DES-OFB is for digital transmissions
actually, that statement is NOT TRUE.
i believe that this was the "way it was" according to motorola SALES upon people switching over to ASTRO from analog.
OFB is (and was) the strongest encryption available to normal everyday Moto customers - and it shares the same key length as DES/DES-XL. This is evident by the use of a T3011DX (old style) Keyloader to load both XL and OFB keys (same loader - same key can go into either an XL or an OFB slot)
i am no expert in the math used to generate the ciphers, but the key strength is the same when comparing OFB and XL.
recovered audio quality is moot as OFB CANNOT ENCRYPT ANALOG TRAFFIC
methinks this is why moto has sold so many "dual mode" DES-XL / DES-OFB secure modules.... XL for the analog side and OFB for the digital.
makes no sense really - XL is fine for both... just realize that audio quality using des-xl in analog mode sucks.... (period) and audio quality des-xl in astro mode is.... well, astro voice.
BE VERY LEERY BUYING DES-XL ONLY SECURE BOARDS (Ebay)
most of these boards have VERY old EMC revisions and WILL NOT function in newer radios.
i could continue, but i hope the above is enuf to explain what i mean.
doug
actually, that statement is NOT TRUE.
i believe that this was the "way it was" according to motorola SALES upon people switching over to ASTRO from analog.
OFB is (and was) the strongest encryption available to normal everyday Moto customers - and it shares the same key length as DES/DES-XL. This is evident by the use of a T3011DX (old style) Keyloader to load both XL and OFB keys (same loader - same key can go into either an XL or an OFB slot)
i am no expert in the math used to generate the ciphers, but the key strength is the same when comparing OFB and XL.
recovered audio quality is moot as OFB CANNOT ENCRYPT ANALOG TRAFFIC
methinks this is why moto has sold so many "dual mode" DES-XL / DES-OFB secure modules.... XL for the analog side and OFB for the digital.
makes no sense really - XL is fine for both... just realize that audio quality using des-xl in analog mode sucks.... (period) and audio quality des-xl in astro mode is.... well, astro voice.
BE VERY LEERY BUYING DES-XL ONLY SECURE BOARDS (Ebay)
most of these boards have VERY old EMC revisions and WILL NOT function in newer radios.
i could continue, but i hope the above is enuf to explain what i mean.
doug
Last edited by batdude on Mon Dec 13, 2004 1:20 pm, edited 2 times in total.
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"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
batdude.......
Your reply intrigues me!
Especially the statement:
" recovered audio quality is moot as OFB CANNOT ENCRYPT DIGITAL TRAFFIC "
which refers to my 1st question:
"With the DES-XL Tx default unselected in each Trunking System, is DES-OFB then the algorithm used when the radios have the dual-hybrid UCM with DES-XL/DES-OFB?"
I read this as, "If you don't specify DES-XL as the Tx Default for all trunked transmissions, the DES-OFB is used" for both analog and ASTRO systems......regardless.
Is this not how to interpret it?[/img]
Your reply intrigues me!
Especially the statement:
" recovered audio quality is moot as OFB CANNOT ENCRYPT DIGITAL TRAFFIC "
which refers to my 1st question:
"With the DES-XL Tx default unselected in each Trunking System, is DES-OFB then the algorithm used when the radios have the dual-hybrid UCM with DES-XL/DES-OFB?"
I read this as, "If you don't specify DES-XL as the Tx Default for all trunked transmissions, the DES-OFB is used" for both analog and ASTRO systems......regardless.
Is this not how to interpret it?[/img]
re-read the above -
it had a typo in it...
if you uncheck DES-XL transmit default, OFB will encrypt ALL your astro channels.
if you try to transmit on an ANALOG CHANNEL with OFB (i.e. the box STILL unchecked) - the radio bonks with ILLEGAL KEY
doug
it had a typo in it...
if you uncheck DES-XL transmit default, OFB will encrypt ALL your astro channels.
if you try to transmit on an ANALOG CHANNEL with OFB (i.e. the box STILL unchecked) - the radio bonks with ILLEGAL KEY
doug
BRAVO MIKE JULIET ALPHA
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
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The Pager Geek
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Let's see if I can stir the pot on this again....
DES-XL vs DES-OFB
Both will encrypt digital.
Recovered audio will be the same in digital. Think about it. All the encryption is doing is coding digital signals (the converted audio to digital from the vocoder.) It's just shuffling the digital audio bits after it's been converted. On the other end, it's reversing the shuffle and sending it to the vocoder for Digital to Analog conversion.
Here's the audio path:
Microphone (analog)
Vocoder (converts to digital Astro VIA DSP)
Encryption (Merely shuffles the above data around)
Receiving radio:
Receives scrambled Astro
Astro Gets decrytped by the encryption module
Astro gets converted to Analog and out to the speaker it goes.
It's all one's and zero's unlike analog encryption. Analog encryption WAS the A/D conversion. Based on the sample rate, freq range etc, would yield your recovered audio at the other end.
Hope that clears up Digital Encrypt for now....
tpg
DES-XL vs DES-OFB
Both will encrypt digital.
Recovered audio will be the same in digital. Think about it. All the encryption is doing is coding digital signals (the converted audio to digital from the vocoder.) It's just shuffling the digital audio bits after it's been converted. On the other end, it's reversing the shuffle and sending it to the vocoder for Digital to Analog conversion.
Here's the audio path:
Microphone (analog)
Vocoder (converts to digital Astro VIA DSP)
Encryption (Merely shuffles the above data around)
Receiving radio:
Receives scrambled Astro
Astro Gets decrytped by the encryption module
Astro gets converted to Analog and out to the speaker it goes.
It's all one's and zero's unlike analog encryption. Analog encryption WAS the A/D conversion. Based on the sample rate, freq range etc, would yield your recovered audio at the other end.
Hope that clears up Digital Encrypt for now....
tpg
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ASTROMODAT
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Doug said: "DES-OFB is (and was) the strongest encryption available to normal everyday Moto customers."
AES is much more secure than DES-OFB (256 bit key versus 56 bit key). And, Motorola is pushing AES hard, as it is a $600 option, while the less secure DES-OFB option is $750. More for less, so to speak.
I think Doug's point was probably that there is much more of an installed base of the old legacy DES-OFB than the relatively new AES.
Given Motorola's pricing policy, I suspect we will see a lot more AES being ordered than the legacy DES-OFB.
larry
AES is much more secure than DES-OFB (256 bit key versus 56 bit key). And, Motorola is pushing AES hard, as it is a $600 option, while the less secure DES-OFB option is $750. More for less, so to speak.
I think Doug's point was probably that there is much more of an installed base of the old legacy DES-OFB than the relatively new AES.
Given Motorola's pricing policy, I suspect we will see a lot more AES being ordered than the legacy DES-OFB.
larry
The catch is that most departmetns will balck at spening a whole bunch more for a new KVL when our DX loaders work just fine.
We were offered the -OFB option with our digital upgrade. We didn't for the following reasons:
Exisitng DVP-XL infrastruce using Spectra's, Sabers, XTS3000's with DVP-XL modules
Upgrade was being done over 3 years
Expense of a new KVL
My DX loader works with out X9000 all the way up to our new XTL5000's with DVP-XL installed in them. (Take that you people who want to hear our coffee orders!)
What's the REAL need? There isn't.
Unless you are a federal agency with real secuirty concerns, there isn't a real threat for day to day law enforcement to replace something that isn't truley comprimised.
We were offered the -OFB option with our digital upgrade. We didn't for the following reasons:
Exisitng DVP-XL infrastruce using Spectra's, Sabers, XTS3000's with DVP-XL modules
Upgrade was being done over 3 years
Expense of a new KVL
My DX loader works with out X9000 all the way up to our new XTL5000's with DVP-XL installed in them. (Take that you people who want to hear our coffee orders!)
What's the REAL need? There isn't.
Unless you are a federal agency with real secuirty concerns, there isn't a real threat for day to day law enforcement to replace something that isn't truley comprimised.
Lowband radio. The original and non-complicated wide area interoperable communications system
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allplowedout
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question for PJ
Just wondering, based on your statement of the following:
My DX loader works with out X9000 all the way up to our new XTL5000's with DVP-XL installed in them. (Take that you people who want to hear our coffee orders!)
Does that mean that a standard t3011dx kvl will load XTL and xts 5000 radios?
I thought for some reason that you needed a kvl3000 to load anything XTS.
Correct me if I'm wrong.
My DX loader works with out X9000 all the way up to our new XTL5000's with DVP-XL installed in them. (Take that you people who want to hear our coffee orders!)
Does that mean that a standard t3011dx kvl will load XTL and xts 5000 radios?
I thought for some reason that you needed a kvl3000 to load anything XTS.
Correct me if I'm wrong.
..
the T3011 D X loader will load anything out there with DES 56bit keys, including XL, OFB and plain DES.
AES is the "gotcha" - if you want/need AES, you must upgrade to the KVL3000+
doug
AES is the "gotcha" - if you want/need AES, you must upgrade to the KVL3000+
doug
BRAVO MIKE JULIET ALPHA
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.