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"How often do resets happen? Answer: if you're using WhatsApp or Signal, all the freaking time. With those apps, you throw away the crypto and just start trust

"How often do resets happen? Answer: if you're using WhatsApp or Signal, all the freaking time. With those apps, you throw away the crypto and just start trusting the server: (1) whenever you switch to a new phone; (2) whenever any partner switches to a new phone; (3) when you factory-reset a phone; (4) when any partner factory-resets a phone, (5) whenever you uninstall and reinstall the app, or (6) when any partner uninstalls and reinstalls. If you have just dozens of contacts, resets will affect you every few days." I guess I don't have "dozens of contacts", but getting a new phone/resetting a phone isn't really that common of a thing in my circle. I feel like for the average user, they wouldn't do this with their phone more than like once every year or two. So I guess if you have like 600 people you talk to on these apps regularly then that works out to daily, but for me at least this isn't that big of a deal and was pretty much understood from the outset.

mhluongo 8y ago
I've had to do it 4-5 times myself (busted phone, water, upgrade). I think it's possible to export the keys (at very least the message history) to avoid this, but if I need to verify with someone I actually fall back on... Keybase :)
idlewords 8y ago
Also (I believe) when you swap out SIM cards, which is routine behavior in parts of the world.
- viraptor 8y ago
  That's not the case. You don't even need a sim card for WhatsApp.
  - icebraining 8y ago
    Can confirm, I used to run it on a WiFi-only tablet, having confirmed the number of my featurephone (which didn't have WhatsApp at all).
  - OJFord 8y ago
    You can't login (on Android at least) without receiving a text message with a verification code.
    - viraptor 8y ago
      That doesn't mean the process depends on a sim card. You can send the code to any number which can receive texts. (including landlines in many cases)
      - OJFord 8y ago
        No you can't, I tried that, it doesn't let you enter the code yourself, it requires permission to read SMS, and then reads the received verification code itself.
- tyfon 8y ago
  I just swapped sim card since I switched provider, same with my wife and we didn't have any resets. I have about 15 people on signal an I've seen a reset once or twice maybe in total.
  - idlewords 8y ago
    My bad, I'm sorry to misinform people!
CharlesColeman 8y ago
> I guess I don't have "dozens of contacts", but getting a new phone/resetting a phone isn't really that common of a thing in my circle. I feel like for the average user, they wouldn't do this with their phone more than like once every year or two. It's not to common with me, and I just notify my contacts know I'm about to do it under my old key before I switch, so they know a warning is coming. Then I just reverify next time we meet. I'd probably be more diligent if I actually had something to hide, but I don't, so I'm not.
flafla2 8y ago
This isn't really the issue. From further down on the article: """ There's a very effective attack here. Let's say Eve wants to break into Alice and Bob's existing conversation, and can get in the middle between them. Alice and Bob have been in contact for years, having long ago TOFU'ed. Eve simply makes it look to Alice that Bob bought a new phone: Bob (Eve): Hey Hey Alice: Yo Bob! Looks like you got new safety numbers. Bob (Eve): Yeah, I got the iPhone XS, nice phone, I'm really happy with it. Let's exchange safety numbers at RWC 2020. Hey - do you have Caroline's current address? Gonna surprise her while I'm in SF. Alice: Bad call, Android 4 life! Yeah 555 Cozy Street. So to call most E2E chat systems TOFU is far too generous. It's more like TADA — Trust After Device Additions.1 This is a real, not articifical, problem, as it it creates an opportunity for malicious introductions into pre-existing conversation. Unlike real TOFU...by the time someone is interested in your TOFU conversation, they can't break in. With TADA, they can. """ The quote you linked is relevant because it means that you can't simply ignore this problem; resets are fairly common, common enough that you can't just delete the key-loser's account (for example). However it doesn't have anything to do with the actual security flaw (if we want to call it that, it's really more of a UX / messaging problem) being discussed.
- thinkloop 8y ago
  That exchange is not realistic, it's easy to ID family or friends by how they conversate. At worst you can ask a challenge question. The prompt that a device has changed is perfect to heighten senses for a quick ID. I disagree that physical contact is necessary as TFA (and industry lore) seem to recommend: > You must now reestablish identity, and in almost all cases, this means meeting in person and comparing "safety numbers" with every last one of your contacts Perhaps the alert could be a little more alerty and in red and read something along the lines of "Hey! Your buddy's safety code has changed, make sure they sound normal and aren't acting weird and creepy asking for information"
  - dabernathy89 8y ago
    How many people are realistically going to pester their friends & relatives with "challenge questions"? I bet even the majority of folks in the HN crowd don't/wouldn't.
dabernathy89 8y ago
I lost my message history on Whatsapp recently just because I decided to rollback from the Android Q beta. Doesn't always have to be a new piece of hardware.
- Tomte 8y ago
  Also Android to Windows phone to Android to iPhone. All of those transitions lost all chat history.
seany 8y ago
I've migrated signal from 3 different phones, along with history and crypto. Signal supports backups that are movable.
- emerongi 8y ago
  Only on Android
  - seany 8y ago
    Ah, I didn't realize that. I've only used it on rooted android phones.
    - velosol 8y ago
      Signal now uses the Android hardware keystore such that you cannot use a root app like TiBackup to move the Signal data around anymore. Instead you have to use Signal's built-in backup and then place the backup on the new phone and setup Signal again (generating a new ID key).
      - seany 8y ago
        I've used both. You can use ti to move the signal specific backup over. Did this just a few days ago.
        velosol 8y ago
        That seems nicer than the method without Ti requiring you to find the backup and move it 'by hand' to the right place on the new phone.
- AgentME 8y ago
  How many people do that? If enough people don't do that and resets become normalized, then it's bad. It doesn't matter if you always do backups when switching devices if resets have been normalized to everyone you talk to, an attacker steals your number, does a reset, and none of your contacts question the reset.
MisterTea 8y ago
> I guess I don't have "dozens of contacts", but getting a new phone/resetting a phone isn't really that common of a thing in my circle. What income bracket is your circle? Just going to reminisce a bit here... I come from a family business that used a lot of manual labor from the local neighborhood here in south Queens, NYC. I spent a lot of time with guys in late teens and 20's, mainly black and hispanic kids looking to make some decent side money. They came from low income backgrounds and were poorly educated. This leads to a very unstable life where money really is scarce. They frequently changed phone numbers due to: "crazy" ex, owes money to scary people, owes child/alimony support, owes the government, commits crimes and uses frequent burners, did jail time, or the #1 reason; out of minutes and no money to put on the prepaid plan. They used prepaid plans as they could refill accounts using cash at physical phone stores or check cashing stores because they don't have a computer or bank account. No phone service means no internet. Most of those guys were good people who I got along with just fine. Ignorance really is a terrible thing.
- el_cujo 8y ago
  >What income bracket is your circle? High enough that they can afford an iPhone but low enough that they treat it like a treasure they don't want to have to replace unless they've had it at least five years. I'm surprised at your suggestion that lower income people would be more likely to go through phones. I could definitely understand this for cheap flip phones on a pre-paid plan, but it was my understanding that Signal and WhatsApp are smartphone-only apps, so I figured lower income people especially wouldn't be flying through phones that cost hundreds of dollars.
  - jrochkind1 8y ago
    As someone who only reluctantly got their first smartphone in the past year (yes, I'm a computer programmer, I dunno), I can say that cheap flip phones don't really exist anymore in the US. You can generally get a cheap smartphone cheaper than a cheap fliphone, in 2019. For instance, you can get smartphones for well under $50 from Cricket, once every 90 days per account. They are locked to Cricket, but you don't actually have a contract, you can abandon them at any time with no penalty. Yes, the cheapest smartphones are gonna be _really bad_. But in the past year-ish, perfectly usable smartphones available around $100-$160 became a thing (carrier locked but no contract). (Flip phones have become _really bad_ too though. Flip phones available in 2019 have worse battery life and worse performance/UX than flip phones of 5 years ago. like press a button wait 1s+ for something to happen bad UX) Flip phones are pretty much gone, I don't think they are a thing poor people use anymore. They might be a thing old people use, or that people attempting to have an anonymous disposable phone use. They don't generally make sense any more as a cost conscious thing, plus if you're poor you don't want to be reminded that you're different from "everyone else" everytime you look at your phone. Incredibly cheap (crappy) smart phones are available, and relatively affordable reasonable ones too. (Plus, not just for poor people these days, but especially if you're poor, your phone is probably your only computer and only internet access).

mhluongo 8y ago

I've had to do it 4-5 times myself (busted phone, water, upgrade). I think it's possible to export the keys (at very least the message history) to avoid this, but if I need to verify with someone I actually fall back on... Keybase :)

idlewords 8y ago

Also (I believe) when you swap out SIM cards, which is routine behavior in parts of the world.

viraptor 8y ago
That's not the case. You don't even need a sim card for WhatsApp.
- icebraining 8y ago
  Can confirm, I used to run it on a WiFi-only tablet, having confirmed the number of my featurephone (which didn't have WhatsApp at all).
- OJFord 8y ago
  You can't login (on Android at least) without receiving a text message with a verification code.
  - viraptor 8y ago
    That doesn't mean the process depends on a sim card. You can send the code to any number which can receive texts. (including landlines in many cases)
    - OJFord 8y ago
      No you can't, I tried that, it doesn't let you enter the code yourself, it requires permission to read SMS, and then reads the received verification code itself.
tyfon 8y ago
I just swapped sim card since I switched provider, same with my wife and we didn't have any resets. I have about 15 people on signal an I've seen a reset once or twice maybe in total.
- idlewords 8y ago
  My bad, I'm sorry to misinform people!

CharlesColeman 8y ago

> I guess I don't have "dozens of contacts", but getting a new phone/resetting a phone isn't really that common of a thing in my circle. I feel like for the average user, they wouldn't do this with their phone more than like once every year or two. It's not to common with me, and I just notify my contacts know I'm about to do it under my old key before I switch, so they know a warning is coming. Then I just reverify next time we meet. I'd probably be more diligent if I actually had something to hide, but I don't, so I'm not.

flafla2 8y ago

This isn't really the issue. From further down on the article: """ There's a very effective attack here. Let's say Eve wants to break into Alice and Bob's existing conversation, and can get in the middle between them. Alice and Bob have been in contact for years, having long ago TOFU'ed. Eve simply makes it look to Alice that Bob bought a new phone: Bob (Eve): Hey Hey Alice: Yo Bob! Looks like you got new safety numbers. Bob (Eve): Yeah, I got the iPhone XS, nice phone, I'm really happy with it. Let's exchange safety numbers at RWC 2020. Hey - do you have Caroline's current address? Gonna surprise her while I'm in SF. Alice: Bad call, Android 4 life! Yeah 555 Cozy Street. So to call most E2E chat systems TOFU is far too generous. It's more like TADA — Trust After Device Additions.1 This is a real, not articifical, problem, as it it creates an opportunity for malicious introductions into pre-existing conversation. Unlike real TOFU...by the time someone is interested in your TOFU conversation, they can't break in. With TADA, they can. """ The quote you linked is relevant because it means that you can't simply ignore this problem; resets are fairly common, common enough that you can't just delete the key-loser's account (for example). However it doesn't have anything to do with the actual security flaw (if we want to call it that, it's really more of a UX / messaging problem) being discussed.

thinkloop 8y ago
That exchange is not realistic, it's easy to ID family or friends by how they conversate. At worst you can ask a challenge question. The prompt that a device has changed is perfect to heighten senses for a quick ID. I disagree that physical contact is necessary as TFA (and industry lore) seem to recommend: > You must now reestablish identity, and in almost all cases, this means meeting in person and comparing "safety numbers" with every last one of your contacts Perhaps the alert could be a little more alerty and in red and read something along the lines of "Hey! Your buddy's safety code has changed, make sure they sound normal and aren't acting weird and creepy asking for information"
- dabernathy89 8y ago
  How many people are realistically going to pester their friends & relatives with "challenge questions"? I bet even the majority of folks in the HN crowd don't/wouldn't.

dabernathy89 8y ago

I lost my message history on Whatsapp recently just because I decided to rollback from the Android Q beta. Doesn't always have to be a new piece of hardware.

Tomte 8y ago
Also Android to Windows phone to Android to iPhone. All of those transitions lost all chat history.

seany 8y ago

I've migrated signal from 3 different phones, along with history and crypto. Signal supports backups that are movable.

emerongi 8y ago
Only on Android
- seany 8y ago
  Ah, I didn't realize that. I've only used it on rooted android phones.
  - velosol 8y ago
    Signal now uses the Android hardware keystore such that you cannot use a root app like TiBackup to move the Signal data around anymore. Instead you have to use Signal's built-in backup and then place the backup on the new phone and setup Signal again (generating a new ID key).
    - seany 8y ago
      I've used both. You can use ti to move the signal specific backup over. Did this just a few days ago.
      - velosol 8y ago
        That seems nicer than the method without Ti requiring you to find the backup and move it 'by hand' to the right place on the new phone.
AgentME 8y ago
How many people do that? If enough people don't do that and resets become normalized, then it's bad. It doesn't matter if you always do backups when switching devices if resets have been normalized to everyone you talk to, an attacker steals your number, does a reset, and none of your contacts question the reset.

MisterTea 8y ago

> I guess I don't have "dozens of contacts", but getting a new phone/resetting a phone isn't really that common of a thing in my circle. What income bracket is your circle? Just going to reminisce a bit here... I come from a family business that used a lot of manual labor from the local neighborhood here in south Queens, NYC. I spent a lot of time with guys in late teens and 20's, mainly black and hispanic kids looking to make some decent side money. They came from low income backgrounds and were poorly educated. This leads to a very unstable life where money really is scarce. They frequently changed phone numbers due to: "crazy" ex, owes money to scary people, owes child/alimony support, owes the government, commits crimes and uses frequent burners, did jail time, or the #1 reason; out of minutes and no money to put on the prepaid plan. They used prepaid plans as they could refill accounts using cash at physical phone stores or check cashing stores because they don't have a computer or bank account. No phone service means no internet. Most of those guys were good people who I got along with just fine. Ignorance really is a terrible thing.

el_cujo 8y ago
>What income bracket is your circle? High enough that they can afford an iPhone but low enough that they treat it like a treasure they don't want to have to replace unless they've had it at least five years. I'm surprised at your suggestion that lower income people would be more likely to go through phones. I could definitely understand this for cheap flip phones on a pre-paid plan, but it was my understanding that Signal and WhatsApp are smartphone-only apps, so I figured lower income people especially wouldn't be flying through phones that cost hundreds of dollars.
- jrochkind1 8y ago
  As someone who only reluctantly got their first smartphone in the past year (yes, I'm a computer programmer, I dunno), I can say that cheap flip phones don't really exist anymore in the US. You can generally get a cheap smartphone cheaper than a cheap fliphone, in 2019. For instance, you can get smartphones for well under $50 from Cricket, once every 90 days per account. They are locked to Cricket, but you don't actually have a contract, you can abandon them at any time with no penalty. Yes, the cheapest smartphones are gonna be _really bad_. But in the past year-ish, perfectly usable smartphones available around $100-$160 became a thing (carrier locked but no contract). (Flip phones have become _really bad_ too though. Flip phones available in 2019 have worse battery life and worse performance/UX than flip phones of 5 years ago. like press a button wait 1s+ for something to happen bad UX) Flip phones are pretty much gone, I don't think they are a thing poor people use anymore. They might be a thing old people use, or that people attempting to have an anonymous disposable phone use. They don't generally make sense any more as a cost conscious thing, plus if you're poor you don't want to be reminded that you're different from "everyone else" everytime you look at your phone. Incredibly cheap (crappy) smart phones are available, and relatively affordable reasonable ones too. (Plus, not just for poor people these days, but especially if you're poor, your phone is probably your only computer and only internet access).