That means that the provider always knows if a file is shared across multiple users (even if they don't know what the file is) and given a cleartext file they can always check if somebody has it stored on the service. It's not ideal at all if you want good privacy.

SpiderOak is explicitly supposed not to do that[1] to avoid these issues, however I refuse to recommend them until they finally decide to release an open source client and 2FA support so caveat emptor.

Anyway, in this case it's irrelevant because Apple has access to the keys anyway, it's only supposed to prevent the third party (Google Cloud in this case) from having access to the files.

[1] https://spideroak.com/resources/encryption-white-paper in the "Data Deduplication" section.

This is particularly space saving if a particular file type was chunked cleverly so that static parts of the file's structure were stored away from dynamic parts (Microsoft's Office XML formats for example could definitely be split this way).

Hetzner charges less than half of that for their storage solution, and that's without de-duplication[1].

Does decreasing the security of their users & not offering end-to-end encryption save them even more money? Sure, but I don't see how it couldn't be profitable without it, seeing as you can easily buy non-de-duplicated cloud storage for way less from other providers.

1. https://www.hetzner.com/storage-box?country=us

Don't forget that the price includes VAT and other taxes. General infrastructure costs, including traffic. Redundancy. Backups. I don't think they're turning much of a profit, but offer it because it makes their platform more attractive.

I have a 2TB family plan that I'm paying $10/mo for, a total of 135GB is used. Most of that usage is from iCloud Photo Library, and while I could use the 200GB plan I'd rather just pay the extra to have effectively unlimited space and not worry about needing to upgrade the plan, especially as I record video in 4K by default now.

I'm sure I'm not the only person who does this, $10/mo is probably nothing to the vast majority of people on HN compared to the hassle of worrying about whether we have enough storage or not.

HEVC/H.265 introduced in iOS 11 largely makes shooting 4K on an iOS device cost _roughly_ the same in storage terms as 1080p/H.264 did, so recording in 4K doesn't really move the storage needle here like it used to either, assuming of course you have an iPhone 7 or newer.

Same boat 100%... Family sharing, 2TB plan, have my wife and mother in the family. Combined we use less than 200GB, but I am happy to pay for more storage rather than deal with tech support calls from them two when we go over 200GB and they get error messages popping up. :P

I do also pay for Office 365 though, $100/yr is significantly cheaper than purchasing Office for every computer in my house.

Apple’s $10 is absolutely not a good deal.

Personally, I'm using seafile on a server, it's cheaper than iCloud or Dropbox, with more storage, and more custom functionality. Many NAS nowadays support Nextcloud out of the box.

You don’t have to dumb down things unnecessarily. If a person can buy a smart home device, plug it in and configure it, or an Apple TV, or a computer, then they can also get one of the simpler NAS, and sync with that.

Geographical redundancy and low-latency data transport are nontrivial factors in pricing cloud storage.

(Which is kind of a shame because a truly bulletproof, user-friendly NAS might be an interesting product. Who is going to be the Apple to Synology's Microsoft?)

It would have to be very, very large to justify the claim that it turns a previously non-cost-effective service into a cost-effective one, especially as prices have been dropping for some time and would hypothetically have simply not dropped as fast if this was the case.

* Offer to charge less usage if a duplicate block is detected, but allow users to pay full price for privately-salted storage. This is similar in principle to how Data Saver works on your mobile device (opt-in to allow a man-in-the-middle to compress or downsample your data)

a) Once you know the chunk size, you can determine based on pricing whether another customer has that data, which can have huge privacy implications.

E.g. let's say we both work at the same company and get the same salary statement PDF aside from the dollar number & your name (which I know).

I can simply brute-force craft a file that changes that number around and upload it to iCloud, when I stop paying for storage I know I've cracked what's on your drive.

In any case, I'd be surprised if Apple's not already leaking this information due to caching in a way that could be revealed via timing attacks.

b) It'll lead to hugely erratic pricing for consumers. E.g. let's say you download 100TB of movies from BitTorrent, now you pay almost nothing for it, but if everyone else deletes their copies pricing for you will go up.

Apple could mitigate that by never raising the price on a given chunk, but that just leaves them paying for it, and it's easily abused. Open two accounts, upload the same data, then delete it from one account, pay 1/2 for storage.

Not completely, I would think. Google may be able to discover whether any user stores file F in iCloud by creating an iCloud account for themselves and uploading the file to it. If that doesn’t create a new file, it already was there before. Depending on what exactly Apple stores on iCloud, they may even be able to detect how many users or (unlikely) even which users store the file.

I don’t see how they could use it, and don’t think they would use it, but Google also has a large data set of email messages and attachments sent between iCloud and gmail accounts that they could somehow use to correlate activity between their gmail servers and the “iCloud on Google cloud” servers.

I assume some other people do this as well.