Filippo Valsorda

@FiloSottile elsewhere / Cryptogopher / Go crypto maintainer / Professional Open Source maintainer / RC F'13, F2'17 

https://mkcert.dev / https://age-encryption.org / https://filippo.io/newsletter

🕳️ “Gaze not into the abyss, lest you become recognized as an abyss domain expert, and they expect you keep gazing into the damn thing.” —Nick Mathewson (npub18ky…l6yq)

Location: Rome 🇮🇹
Pronouns: he/him
Website: https://filippo.io
Twitter: https://twitter.com/FiloSottile

Last Notes

2025-08-31 13:54:02 UTC

There's a bit of commotion on Lobsters because an unpleasant-but-technically-correct user finally got banned, and I realized that an unpopular opinion of mine is that moderators are always right.
I don't care about the letter of the CoC. I don't care about transparency, even. Moderation is the fundamentally human and nuanced big-picture job that shapes a community.
https://cdn.masto.host/abyssdomainexpert/media_attachments/files/115/123/712/178/230/773/original/42748b9cdd676f14.png

2025-06-21 18:29:26 UTC

Looks like the same poorly implemented Android CT library that broke a lot of apps a couple years ago... did it again 🤦‍♂️
https://github.com/appmattus/certificatetransparency/issues/143#issuecomment-2993688741

2025-05-20 22:08:34 UTC

If Certificate Transparency logs were available as torrents, would you help seeding them?
If so, with how much storage and with what client?
I’m not sure how we’d update the torrent as the log grows. Does BEP 38 deduplication work with RSS feeds?

2025-05-19 19:07:59 UTC

Three Trail of Bits engineers audited the core Go cryptography packages for a month, and found only one low-sev security issue... in the legacy unsupported Go+BoringCrypto integration we're replacing! 🍾
Years of team efforts on testing, limiting complexity, safe APIs, and readability have paid off! ✨
Yes I am taking a victory lap. No I am not sorry. 🏆
https://go.dev/blog/tob-crypto-audit

2025-05-02 21:36:51 UTC

Running a full-network Bluesky relay costs less ($19) than my beefy but ~single user Mastodon hosted instance ($24).
People underestimate how much data optimized software can move through efficient protocols on modern non-cloud hardware.
https://whtwnd.com/bnewbold.net/3lo7a2a4qxg2l

2025-05-02 21:36:51 UTC

- reply

The relay is the supposedly centralized part of Bluesky because “too big” to run! $19/month!
The bsky.app AppView is bigger but every Mastodon instance is an AppView (and PDS), and if you were ok with Mastodon-style partial views of the network, AppViews would be cheap too.

2025-03-21 09:22:48 UTC

It’s disheartening to see AI reactionism lead my community to a 180° on copyright.
Everyone is merrily attacking LibGen now. If it didn’t exist, big tech companies would still find training data, it just wouldn’t be accessible to regular people.

2024-12-11 19:12:39 UTC

Would you pay for Cryptography Dispatches? I am considering using Buttondown's new per-email subscriptions to trick myself into writing more in 2025.
This would be voluntary. Max 1–3 issues per month.
There would be no subscriber-only issues. What you get for your money is motivating me to write more, if that's something you like.
Conversely, this would not be a major source of income. What I get out of it is tricking my brain into doing more writing by setting up a reward system.

2024-11-23 13:52:05 UTC

Is there an open-source web UI for servers that displays system information like pstree, zpool status, fdisk -l, df, ip addr, etc?
I want it to just show current info about the machine it's running on, not rely on a metrics pipeline.
Ideally it would be read-only, extensible, and a single-binary Go program, or something as simple to deploy.

2024-09-19 15:03:10 UTC

Cat's out of the bag: I am pursuing a native FIPS 140-3 validation for the Go standard library.
Trying to do it right, making it seamless and without compromising on security.
First time a Go module is validated. Wish me well. And consider sponsoring!
https://go.dev/issue/69536

2024-09-16 13:35:58 UTC

Oh shit the vDSO implementation of getrandom() landed in Linux 6.11.
Might remove one of the last performance objections ot using the kernel CSPRNG for everything, the syscall overhead.
I have a large CL chain for crypto/rand, might as well add support for that...

2024-09-03 16:44:40 UTC

A couple notes about the Infineon timing side channel affecting most YubiKeys.
1. yubikey-agent is unaffected in the evil maid threat model as the attacker needs physical access *and PIN*
2. lol, Infineon
3. Go mitigates timing side-channels in ECDSA nonce inversion by not being clever and just using Fermat's little theorem, which is as simple as a constant time exponentiation by p - 2 (which can be optimized with @npub18qv…vtfq's addchain)
https://ninjalab.io/eucleak/
https://www.yubico.com/support/security-advisories/ysa-2024-03/

2024-08-05 22:19:49 UTC

- reply

I’d argue PuTTY is just wrong. No one should use DSA keys, Ed448 is mostly unimplemented, and what does EdDSA even mean as a separate option.