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Meta built large-scale cryptographic monitoring

engineering.fb.com

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Re: Meta built large-scale cryptographic monitoring

#11

Post by pdpi »

bagels wrote: post #7

What it's like to be a Facebook engineer in this context: It's your oncall week, and all of a sudden you get an urgent task that you must resolve in the next few days: Figure out how to replace a crypto algorithm in some component your code depends on or else we tell your manager that you're not playing ball.

When I was there, the experience here would've been more like "you see some comms on Workplace saying this thing went live".

For a small number of people, it would look like "It's your oncall week, and you unexpectedly receive a large diff stack from a complete stranger". Most engineers at Meta won't touch anything related to C++ during their tenure there, and you can safely assume all this stuff would be abstracted away from them.

If you are on a C++ project, odds are that your experience here would be "I'm on-call and got pinged by a random person saying they were submitting a diff stack to implement this feature". Except if your project was sufficiently large, you'd probably have known about this ages ago so the diff wouldn't actually be unexpected, nor the submitter a complete stranger.

Re: Meta built large-scale cryptographic monitoring

#12

Post by [deleted] »

bagels wrote: post #7

What it's like to be a Facebook engineer in this context: It's your oncall week, and all of a sudden you get an urgent task that you must resolve in the next few days: Figure out how to replace a crypto algorithm in some component your code depends on or else we tell your manager that you're not playing ball.

[deleted]

Re: Meta built large-scale cryptographic monitoring

#13

Post by [deleted] »

smitelli wrote: post #3

Scribe[1], Scuba[2], Hive[3], and folly[4]. It's neat for sure, but speaking as an outsider without the resources to learn (much less create!) an entire universe of data infrastructure and SDKs, it feels like I'm in the corner eating dinner at the kids' table. At any rate, I'm glad somebody out there is doing this stuff. [1]: https://engineering.fb.com/2019/10/07/core-infra/scribe/ [2]: https://research.facebook.com/…

[deleted]

Re: Meta built large-scale cryptographic monitoring

#14

Post by jamra »

bagels wrote: post #7

What it's like to be a Facebook engineer in this context: It's your oncall week, and all of a sudden you get an urgent task that you must resolve in the next few days: Figure out how to replace a crypto algorithm in some component your code depends on or else we tell your manager that you're not playing ball.

You’d be calling libraries that are vetted by the security team. Engineering at Meta is a lot like coloring with crayons. It’s very limiting but the infra does a lot for you.

Re: Meta built large-scale cryptographic monitoring

#15

Post by HeatrayEnjoyer »

tptacek wrote: post #4
cactusplant7374 wrote: post #2

> Since there is a limit to how much data a symmetric cryptographic key can protect Is this regulatory related or self imposed?

Neither: it's because (overgeneralizing) there are bounds on the number of times nonces can be generated under a key without risk of collision, which in AEAD constructions is a devastating event.

But shouldn't that bound be astronomical?

Re: Meta built large-scale cryptographic monitoring

#16

Post by stavros »

HeatrayEnjoyer wrote: post #15
tptacek wrote: post #4

Earlier quoted context omitted.

Neither: it's because (overgeneralizing) there are bounds on the number of times nonces can be generated under a key without risk of collision, which in AEAD constructions is a devastating event.

But shouldn't that bound be astronomical?

I'm fairly out of my depth here, but the birthday paradox is a harsh mistress.

Re: Meta built large-scale cryptographic monitoring

#17

Post by tptacek »

HeatrayEnjoyer wrote: post #15
tptacek wrote: post #4

Earlier quoted context omitted.

Neither: it's because (overgeneralizing) there are bounds on the number of times nonces can be generated under a key without risk of collision, which in AEAD constructions is a devastating event.

But shouldn't that bound be astronomical?

GCM is like 4 billion messages, which is not astronomical at Facebook's scale.

Re: Meta built large-scale cryptographic monitoring

#18

Post by yodsanklai »

bagels wrote: post #7

What it's like to be a Facebook engineer in this context: It's your oncall week, and all of a sudden you get an urgent task that you must resolve in the next few days: Figure out how to replace a crypto algorithm in some component your code depends on or else we tell your manager that you're not playing ball.

triage and redirect to L7+ colleague

Re: Meta built large-scale cryptographic monitoring

#19

Post by loeg »

bagels wrote: post #7

What it's like to be a Facebook engineer in this context: It's your oncall week, and all of a sudden you get an urgent task that you must resolve in the next few days: Figure out how to replace a crypto algorithm in some component your code depends on or else we tell your manager that you're not playing ball.

In my experience with the cryptographic security space at Facebook, what happens is the security team reaches out to you and starts a conversation. You collaboratively establish the severity, acceptable mitigation options, and appropriate timeline. There might be a little bikeshedding over various degrees of ideal option (it's more fun for the crypto guys that way). They might volunteer to do the work. You review the diffs, they're good, it lands.

They're smart people and the team knows how to collaborate with random infra/product teams.

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