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Russia issues threat to GPS satellites

gpsworld.com

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Re: Russia issues threat to GPS satellites

#21

Post by dogma1138 »

whoknowswhat11 wrote: post #16
dogma1138 wrote: post #14

Earlier quoted context omitted.

I’m not sure why you are being so hostile, but the GP is quite correct. Clock sync error is one of the most common reasons why credit card terminals fail to process a transaction. GPS is one of the most common ways to set up a clock, and whilst the terminals and ATMs usually don’t get GPS time directly but through an NTP server the NTP servers do set their time via GPS. Even if you have an atomic clock it’s usually s…

You cannot overdraw your account because your computers clock is wrong. You cannot overdraw your account because there is an issue with a credit card terminal around clock sync. This simply cannot happen. If it can, let me suggest that whoever is writing the account debit code wrap the balance check and debit in a transaction. You can easily stick a rackmount atomic clock in your data center. NTP can source from a va…

No one said you can overdraw your account but the terminal would simply refuse to connect or the transaction would be rejected by the server due to clock sync issues. Also no one said that the terminals get a GPS signal either but if the clock is off on them vs the server they will fail, I have worked on a lot of payment systems.

Rackmount atomic clocks still need a GPS signal today to be set or they have to be pre-set in a central location and then distributed.

Time syncing used to be a PITA and now it’s easy due to GPS so pretty much every protocol has a very narrow time tolerance. My work HP laptop drifts 3-5 min over the weekend of the VPN because it’s not set to an external time server and all hell breaks loose.

Yes civilization will not end over night but it would have a major impact we will find ways to get by but there will be havoc and the financial damages will be in the trillions heck the disruption to shipping and logistics alone would be immense nearly every one and every thing today is reliant on GPS either directly or indirectly.

Re: Russia issues threat to GPS satellites

#22

Post by mikewarot »

whoknowswhat11 wrote: post #20
mikewarot wrote: post #15

Earlier quoted context omitted.

>you can use the NIST broadcasts. Which recently had their funding threatened, AND aren't reliably available across the entire US anyway. A cesium clock does no good if it isn't synched to the rest of the world.

The entire point of a cesium clock is that it does NOT need to remain linked all the time. That is literally why you would get one in your rack. So your statement is totally false. In fact, the BENEFIT of a cesium clock is the incredible stability in the absence of a sync.

Cesium tubes have a 5-7 year service life. They need to be synced up to the rest of the world, or they can't tell you the time. They do drift, a bit. If you're trying to keep clock in sync to the second, they'll do as long as the tube lasts, but if you're trying to keep systems in sync to the microsecond, they need to be synced up from time to time. The stability of an HP5061a Cesium Beam clock is about 10^-11

If you want to stay within a microsecond, you have to sync it up about every 3 months. This could be done with a mobile atomic clock driven to sync up secondary standards, in the absence of GPS.

Re: Russia issues threat to GPS satellites

#23

Post by whoknowswhat11 »

mikewarot wrote: post #22
whoknowswhat11 wrote: post #20

Earlier quoted context omitted.

The entire point of a cesium clock is that it does NOT need to remain linked all the time. That is literally why you would get one in your rack. So your statement is totally false. In fact, the BENEFIT of a cesium clock is the incredible stability in the absence of a sync.

Cesium tubes have a 5-7 year service life. They need to be synced up to the rest of the world, or they can't tell you the time. They do drift, a bit. If you're trying to keep clock in sync to the second, they'll do as long as the tube lasts, but if you're trying to keep systems in sync to the microsecond, they need to be synced up from time to time. The stability of an HP5061a Cesium Beam clock is about 10^-11 If you…

If you need it you can do something around -12+.

Is this needed for the clock drift in the CC hand terminal that creates these "clock sync" errors that make it so the bank can't figure out my balance / avoid an overdraft?

There is digital radio time code, there is the internet and NTP where you can pull directly from the atomic clock standard, there is GPS. You can get your own atomic clock and get by for a while even IF you need some kind of perfect sync so the credit card reader doesn't have a "clock sync" error.

The claim here is apparently that relatively insane levels of percision are needed so that normal database transactions remain atomic. That I can withdraw cash from an ATM. That I can use my credit card.

I remain skeptical. Withdrawing from an ATM depends on ONE system knowing what your balance is. Your banks. While it might be nice to be accurate to the microsecond, it's not a requirement. To the second is going to be fine. Similarly, when you swipe a credit card, the auth process does a live inquiry (balance, fraud control etc). Again, I'm extremely skeptical of the claims here that we need microsecond SYNCED time for any of this.

Re: Russia issues threat to GPS satellites

#24

Post by mikewarot »

whoknowswhat11 wrote: post #23
mikewarot wrote: post #22

Earlier quoted context omitted.

Cesium tubes have a 5-7 year service life. They need to be synced up to the rest of the world, or they can't tell you the time. They do drift, a bit. If you're trying to keep clock in sync to the second, they'll do as long as the tube lasts, but if you're trying to keep systems in sync to the microsecond, they need to be synced up from time to time. The stability of an HP5061a Cesium Beam clock is about 10^-11 If you…

If you need it you can do something around -12+. Is this needed for the clock drift in the CC hand terminal that creates these "clock sync" errors that make it so the bank can't figure out my balance / avoid an overdraft? There is digital radio time code, there is the internet and NTP where you can pull directly from the atomic clock standard, there is GPS. You can get your own atomic clock and get by for a while eve…

The thing is, once something becomes commonplace, people build in obligations against it without thinking about it. All those layers that civilization depends upon have a cost, and as long as the cost is paid, all is good.

We're talking about the sudden loss of precision timekeeping, which could desync all sorts of things in unexpected ways. It's my understanding that precision time is required to make even the cell phone networks properly operate, and they'd fall apart without it.

If Russia were to take out GPS, the effects would be deep and expensive to correct, if we could. There's a very small, but non-zero chance it could collapse our supply chains. As time goes on, this chance grows, unless there is an active effort to keep backup systems viable. We all know how actively the US maintains infrastructure 8(

Re: Russia issues threat to GPS satellites

#25

Post by whoknowswhat11 »

mikewarot wrote: post #24
whoknowswhat11 wrote: post #23

Earlier quoted context omitted.

If you need it you can do something around -12+. Is this needed for the clock drift in the CC hand terminal that creates these "clock sync" errors that make it so the bank can't figure out my balance / avoid an overdraft? There is digital radio time code, there is the internet and NTP where you can pull directly from the atomic clock standard, there is GPS. You can get your own atomic clock and get by for a while eve…

The thing is, once something becomes commonplace, people build in obligations against it without thinking about it. All those layers that civilization depends upon have a cost, and as long as the cost is paid, all is good. We're talking about the sudden loss of precision timekeeping, which could desync all sorts of things in unexpected ways. It's my understanding that precision time is required to make even the cell…

The claim was about ATM withdrawals and credit card swipes. Ie, without a GPS clock there would be a "clock sync" error in the ATM machine, and no cash could be drawn.

I continue to remain EXTREMELY skeptical of this claim. It makes almost no sense.

Please note that GPS is not the source of time, NIST is, and you can get NIST time in a variety of ways including over the internet if needed. And as I have been describing, many of these described errors are around systems with one source of truth (ie, not google spanner type globally distributed databases). So they make even less sense.

Note I'm familiar with clock skew issues and errors in authentication and other systems. These issues show up when errors are in minutes and seconds not microseconds.

Re: Russia issues threat to GPS satellites

#26

Post by whoknowswhat11 »

dogma1138 wrote: post #21
whoknowswhat11 wrote: post #16

Earlier quoted context omitted.

You cannot overdraw your account because your computers clock is wrong. You cannot overdraw your account because there is an issue with a credit card terminal around clock sync. This simply cannot happen. If it can, let me suggest that whoever is writing the account debit code wrap the balance check and debit in a transaction. You can easily stick a rackmount atomic clock in your data center. NTP can source from a va…

No one said you can overdraw your account but the terminal would simply refuse to connect or the transaction would be rejected by the server due to clock sync issues. Also no one said that the terminals get a GPS signal either but if the clock is off on them vs the server they will fail, I have worked on a lot of payment systems. Rackmount atomic clocks still need a GPS signal today to be set or they have to be pre-s…

> No one said you can overdraw your account

False: The qz article I'm responding to says this.

"When you pull cash from an ATM or swipe your card at the coffee shop, the machine needs to determine the precise time that the transaction occurs to, for example, prevent it from being over-drawn."

Please please explain how this "over-drawn" situation occurs because of a GPS satellite.

> but if the clock is off on them vs the server they will fail, I have worked on a lot of payment systems.

False, CC terminal clocks do not need to be GPS time accurate. When the terminal connects to authenticate, they can update their time. There can be issues with authentication if clock skew is bad, but this requires normal levels of time sync (ie, NTP without GPS will be fine).

Re: Russia issues threat to GPS satellites

#27

Post by dogma1138 »

whoknowswhat11 wrote: post #26
dogma1138 wrote: post #21

Earlier quoted context omitted.

No one said you can overdraw your account but the terminal would simply refuse to connect or the transaction would be rejected by the server due to clock sync issues. Also no one said that the terminals get a GPS signal either but if the clock is off on them vs the server they will fail, I have worked on a lot of payment systems. Rackmount atomic clocks still need a GPS signal today to be set or they have to be pre-s…

> No one said you can overdraw your account False: The qz article I'm responding to says this. "When you pull cash from an ATM or swipe your card at the coffee shop, the machine needs to determine the precise time that the transaction occurs to, for example, prevent it from being over-drawn. " Please please explain how this "over-drawn" situation occurs because of a GPS satellite. > but if the clock is off on them vs…

While the reason is not necessarily correct (although it’s more of an over simplification than an outright error) the terminal needs to have the correct time if not the transaction would not be processed for a myriad of reasons.

The issue is that in the vast chain of networks that a single transaction flows through you have multiple NTP servers each of them taking their own time form a different source which is often backed by GPS.

If GPS services are disrupted globally this would cause payment networks to break down.

Yes there would be a way to recover from it and move away from GPS but you are still missing the point on day-0 of a GPS blackout the global financial system would go down and it would be a mess and it wouldn’t be a mess that is easily sorted…

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