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NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

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Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#51

Post by lazide »

bambax wrote: post #48
cloudbonsai wrote: post #22

Earlier quoted context omitted.

Among the interviews, one with the former engineering director was the most eye-opening for me. https://data.ntsb.gov/Docket/Document/docBLOB?ID=17236880&Fi... It appears that all the engineers -- system designer, material engineer and structural analyst -- thought that OceanGate CEO was going to kill himself: If you ever find , he’s not going to have a whole lot of nice to say. He was very frustrated with the compan…

The number of stupid decisions that went in the design and construction of the Titan is astonishing. One of my favorites was that, after putting on the carbon fiber around the tube, they would sand imperfections to make the surface perfectly smooth, severing layers in the process! It shouldn't require an engineering degree from MIT to recognize this as ill-advised.

Even without that, the material is just wrong. It’s strong in tension, not so much compression. Tends towards sudden brittle fractures. Doesn’t like impacts, as it tends to have issues with delaminating.

It’s just not what you ever want as a sub hull. It’s dumb.

And weight is not even a huge issue for a sub!

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#52

Post by bambax »

lazide wrote: post #51
bambax wrote: post #48

Earlier quoted context omitted.

The number of stupid decisions that went in the design and construction of the Titan is astonishing. One of my favorites was that, after putting on the carbon fiber around the tube, they would sand imperfections to make the surface perfectly smooth, severing layers in the process! It shouldn't require an engineering degree from MIT to recognize this as ill-advised.

Even without that, the material is just wrong. It’s strong in tension, not so much compression. Tends towards sudden brittle fractures. Doesn’t like impacts, as it tends to have issues with delaminating. It’s just not what you ever want as a sub hull. It’s dumb. And weight is not even a huge issue for a sub!

Yes, using carbon fiber was also a very bad decision; it was known for a very long time that it was only good for single-use sub, because after the first dive it was too damaged to continue. In 2014, Virgin Oceanic, which had similar plans with similar technology, closed shop because it didn't make economic sense to build a new sub for each dive.

But weight is absolutely an issue; the basic and tried-and-true metal sphere design allows for only three people. Since size and thickness grow exponentially, making a sphere for more than three people becomes more and more difficult. And it should also be possible to lift the vehicle with a crane.

But if you want to carry paying passengers (like Oceangate did), having only two per dive is very limiting. That's why they went with a tube design, and carbon fiber to limit weight. But it couldn't work, and it didn't.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#53

Post by schiffern »

bambax wrote: post #52
lazide wrote: post #51

Earlier quoted context omitted.

Even without that, the material is just wrong. It’s strong in tension, not so much compression. Tends towards sudden brittle fractures. Doesn’t like impacts, as it tends to have issues with delaminating. It’s just not what you ever want as a sub hull. It’s dumb. And weight is not even a huge issue for a sub!

Yes, using carbon fiber was also a very bad decision; it was known for a very long time that it was only good for single-use sub, because after the first dive it was too damaged to continue. In 2014, Virgin Oceanic, which had similar plans with similar technology, closed shop because it didn't make economic sense to build a new sub for each dive. But weight is absolutely an issue; the basic and tried-and-true metal s…

  >size and thickness grow exponentially
It's a [reverse] pressure vessel, so it follows pressure vessel scaling. Mass scaling is linear with internal volume.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#54

Post by djmips »

netsharc wrote: post #36
djmips wrote: post #25

Earlier quoted context omitted.

Wasn't the pilot Stockton Rush? His wife was alive. Who are you referring to? I tried to check your claim but I couldn't verify it.

There was only one other crew member in that vessel (well, actual crew and not paper "mission specialist"). He was an older gentleman, and it's quite common for older people to have lost their spouse. Was that so hard to figure out?

yeah but he remarried

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#55

Post by londons_explore »

rocqua wrote: post #47
ryan-ca wrote: post #41

Earlier quoted context omitted.

To my knowledge, encoding avoids runs to avoid desynchronization in a way that isn’t encrypted.

This is line coding, often used on wired connections. But reading a hard drive trace isn't quite a wired connection, so the trade-offs are different. Most notably with line coding when using positive and negative voltages it is quite important for the average voltage to be zero to avoid building up a charge difference. Whitening can often be used if the downside to an imbalance or long runs is much lower. Notably in…

> Whitening using any non trivial encryption key seems weird to me.

It's because there was an era when drives were expected to be able to do 'hardware' encryption with a user provided key, so reusing that hardware to also do whitening even if the user didn't provide a key was very convenient.

Plus you get all the other benefits - ie. a single scsi command can 'secure erase' the whole disk in milliseconds by simply changing the stored key.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#56

Post by kasabali »

londons_explore wrote: post #37
cbsks wrote: post #4

Wow. SubC’s software engineering needs some work. They thought the camera’s file system was unencrypted, when it was encrypted. They didn’t know where the keys were to decrypt it. It turned out the key was written unencrypted to a UFS storage device. There was a file written to /mnt/nas/Stills, which indicates that the camera was to writing to a remote file system that wasn’t mounted.

> They thought the camera’s file system was unencrypted, when it was encrypted. Willing to bet plenty of hn readers are unaware of encryption going on at lower layers of the tech stack than they're aware of. For example most hard drives encrypt all data, even when not commanded to, as a way to do 'data whitening' (ie making sure there are even numbers of 0's and 1's in the data stream and not some pattern which might…

If you're talking about SED feature, no, it isn't widespread since it's regarded as an "enterprise" feature and only available in minority of drives (regardless of HDD or SSD). Client or OEM variants of same drives (otherwise identical) lack SED option most of the time and doesn't encrypt data by default.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#57

Post by Terr_ »

jiggawatts wrote: post #15
userbinator wrote: post #12

Earlier quoted context omitted.

They thought the camera’s file system was unencrypted, when it was encrypted. Unfortunately this situation is likely to get more common in the future as the "security" crowd keep pushing for encryption-by-default with no regard to whether the user wants or is even aware of it. Encryption is always a tradeoff; it trades the possibility of unauthorised access with the possibility of even the owner losing access permane…

This is why I always shake my head when the Reddit armchair security experts say "The data wasn't even encrypted!? Amateur hour!" in response to some PII leak. Sure, sure buddy, I'll encrypt all of my PII data so nobody can access it... including the web application server. Okay, fine, I'll decrypt it on the fly with a key in some API server... now the web server had unencrypted access to it, which sounds bad, but th…

Nah bro, you just gotta use homomorphic encryption! /s

That said, encryption at rest is still good in terms of theft or mis-disposal.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#58

Post by londons_explore »

kasabali wrote: post #56
londons_explore wrote: post #37

Earlier quoted context omitted.

> They thought the camera’s file system was unencrypted, when it was encrypted. Willing to bet plenty of hn readers are unaware of encryption going on at lower layers of the tech stack than they're aware of. For example most hard drives encrypt all data, even when not commanded to, as a way to do 'data whitening' (ie making sure there are even numbers of 0's and 1's in the data stream and not some pattern which might…

If you're talking about SED feature, no, it isn't widespread since it's regarded as an "enterprise" feature and only available in minority of drives (regardless of HDD or SSD). Client or OEM variants of same drives (otherwise identical) lack SED option most of the time and doesn't encrypt data by default.

The hardware is still there - they don't make a new asic for the consumer version

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#59

Post by FabHK »

schiffern wrote: post #53
bambax wrote: post #52

Earlier quoted context omitted.

Yes, using carbon fiber was also a very bad decision; it was known for a very long time that it was only good for single-use sub, because after the first dive it was too damaged to continue. In 2014, Virgin Oceanic, which had similar plans with similar technology, closed shop because it didn't make economic sense to build a new sub for each dive. But weight is absolutely an issue; the basic and tried-and-true metal s…

>size and thickness grow exponentially It's a [reverse] pressure vessel, so it follows pressure vessel scaling. Mass scaling is linear with internal volume.

It’s funny how “literally” often means “figuratively” now, and “exponentially” means “polynomially”.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#60

Post by gattr »

cloudbonsai wrote: post #17
watersb wrote: post #5

The SD card on the camera was intact but encrypted. Decrypting the data required a key stored on a separate SOM board, but the SOM was damaged. The investigation team delivered the SOM and SD card to the camera manufacturer in Newfoundland, and they were able to decrypt the card. They found a couple of images, but No data with a timestamp after May 16th was found on the camera, so it is likely that none of the data r…

> No data with a timestamp after May 16th was found on the camera, so it is likely that none of the data recorded on the SD Card were of the accident voyage or dive. Evidently the camera data was recorded to an external SSD card in the mission computer when the accident occurred. The investigation team actually managed to salvage the PC as well: https://data.ntsb.gov/Docket/Document/docBLOB?ID=19169363&Fi... Sadly it…

From the report:

> To conduct the CT scans, the large mass was evaluated by a third-party laboratory under NTSB supervision. This facility had a range of scanners with different power and energy levels and could scan large masses using a rotating table, avoiding the need to rotate the mass itself. Ultimately, the third-party laboratory attempted to image the large mass at a power as high as 320 kilovolts (kV). The scans conducted at 320 kV were not powerful enough to penetrate the object, and as a result, no internal structures or voids were visible, and no memory devices could be identified. The NTSB evaluated using another laboratory with higher power and energy CT scan devices, however, there was concern that increased CT scan energy could damage data stored on any surviving NVM chips. Consequently, higher-energy scans were not pursued.

I'm no expert, but remember reading about neutron imaging ([1]). I'm curious if that was deemed unfeasible, too expensive, or having little chance of success? From Wikipedia:

> X-rays are attenuated based on a material's density. Denser materials will stop more X-rays. With neutrons, a material's likelihood of attenuation of neutrons is not related to its density. Some light materials such as boron will absorb neutrons while hydrogen will generally scatter neutrons, and many commonly used metals allow most neutrons to pass through them.

[1] https://en.wikipedia.org/wiki/Neutron_imaging#Neutron_radiog...

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