2 HN users recommended this talk2 months2016–2022score 2
Years with an HN recommendation, 2007–2026
Recommended whenever ZFS encryption comes up as the authoritative explanation of how it was added and its trade-offs at scale.
Tom Caputi presents the design of native encryption for ZFS at the OpenZFS Developer Summit, including design decisions and how authentication uses checksum fields.
“check out this presentation on how encryption was bolted on ZFS” (HN, 2017)
On the contrary, it makes it suitable for file systems! File systems are not block devices, they are data structures on top of block devices — it's the job of these data structures to keep stuff, such as data, inodes, and... keys, and IVs, and MACs, checksums, etc. TFS uses Speck in XEX mode (edit: I just realized you're the author, so you already know that :). tptacek wrote a nice post about it: [link] and I quote: "If you’re encrypting a filesystem and not disk blocks, still don’t use XTS! Filesystems have format-awareness and flexibility. Filesystems can do a much better job of encrypting a disk than simulated hardware encryption can." Edit: check out this presentation on how encryption was bolted on ZFS: [this video] (slides: [link] ) It's not perfect, but it provides data authentication by reusing checksum fields for storing MACs. Edit 2: also check out bcachefs encryption design doc: [link] (also not perfect, but uses proper AEAD — ChaCha20-Poly1305. I sent some questions and suggestions to the author, but received no reply :/)
How encryption was added to ZFS, with authentication via checksum fields
The problem is that a stream cipher is going to have some per-object uniqueness (a salt, IV, etc.), so by design even if you feed it related input blocks you will get different output blocks. This is, of course, antithetical to deduplication: so you need to check/store the hash of the input before it goes through the cipher. The presentation about ZFS' native encryption[1] covers many of these sorts of trade-offs necessary to do full-disk encryption at scale. [1]: [this video]
Native ZFS encryption may become available soon. It is pending code review: [link] There was a presentation of this by Tom Caputi at the most recent OpenZFS Developer Summit. Slides: [link] Video: [this video] Conference: [link]
Video list and Hacker News comment labels from HackerTube (prompted by @karpathy), released under ODC-By 1.0, built on the open-index/hacker-news archive. Hacker News data is provided by Y Combinator; comments remain the work of their authors. Video titles, channel names and thumbnails belong to their creators and are shown via YouTube. HackerTube Watch is an unofficial edition. Data export of 2026-10-31.
Plays via YouTube's privacy-enhanced embed
5 Hacker News comments
From the HN archive; up to 20 kept per video, favoring different commenters. Recommendations first.
Read more
Citations, criticism and jokes