Look up computer generated holography! It is certainly possible to calculate a hologram of a letter which focuses at some different depth than the screen.
There are issues which arise from restricting the hologram to a real valued grid, like limited FoV and noise, but these are not impossible problems to solve and existing technology is already quite good in terms of image quality.
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I have noticed that Google Shopping is blocking results for "N95 mask" in the UK, making it more difficult to find retailers which sell them. On the other hand there are thousands upon thousands of results on eBay/Amazon, most of which cannot be trusted.
Regarding comsumer NASs having poor security, I completely agree, however it wasn't too relevant to my personal threat model. Backups of my computers (which could potentially compromise credentials) are encrypted before they go on the NAS, and if I needed to sync anything sensitive it would be encrypted locally.
Using my NAS for sharing photos and files with family/friends opens up security holes that encryption at rest wouldn't help with, and I accept the tradeoff of potentially leaking data. What is less acceptable to me is any risk of data loss.
Having recently acquired a NAS for use (among other things) as a single source of truth for photos spanning ~15 years, I have done a lot of research around backups.
These are the threats I have considered and would like to mitigate against, in no particular order:
1. Physical damage or theft to the NAS and supporting hardware (e.g. backup drives in my home).
2. Accidental deletion or corruption of files through user error.
3. Ransomware which targets my NAS. In particular a sophisticated malware author could target common cloud backup destinations by looking for credentials stored on the NAS, and delete any backups, although I have not heard of any such attacks in the wild.
The first threat seems simple enough to mitigate: make regular backups backed by cloud storage, and keep offline credentials for accessing the backup in multiple geographical locations as well as a cloud based password manager.
The second is also not troublesome: use a filesystem which supports versioning and take regular snapshots.
The third is where I have been somewhat disappointed by the options. An effective strategy is to keep an external hard drive which is plugged into the NAS regularly and keeps a clone of the data. However, an extremely cunning malware author could still pre-empt this by corrupting data on plugged in drives. This is extremely unlikely, but here's where I was hoping for better options in cloud backups: effectively all the pieces are in place for immutable backups, except for the tooling.
Options such as restic and rclone don't have good (if any) support for targets which support immutability, such as AWS S3 and BackBlaze B2. My current solution is to use a version of restic which I have patched to not require delete permissions when targeting B2, and very carefully manage API keys so that deleting backups would require compromising my BackBlaze account. In case a script does try to corrupt the backup repository, there are few if any supported ways of accessing a past version of a B2 bucket, although rclone comes very close and could support this very nicely with some minor tweaks to the B2 backend.
I will be keeping a close eye on this, and hopefully if I have the time I can make some PRs to push the open source tooling in this direction.
I use a combination of Signal, WhatsApp and Messenger for communicating with friends and family. Recently I made a series of transitions from Android to iOS and then back to Android, and beside the annoyance of entering account and banking details anew, migrating messages was the main obstacle in the way of a smooth transition.
I am not sentimental about text messages but I did have photos which I had received from other people and wanted to keep. The only way to do this in the iOS -> Android case was to go through all of my threads in WhatsApp and Signal, save the photos I wanted to keep to my Camera Roll (??) and then copy them to my computer.
On Android, WhatsApp stores its data in the data partition, and Signal can either save photos to its own folder or export a backup, although I did not look into how to decrypt the backup.
Ultimately what drove me back to Android was that iOS did not give me control of my data in the way I am used to, despite some of the much touted privacy advantages.