Elektrine
EN
Log in Register
Paige Chat Timeline Communities Gallery Videos Email DNS VPN Uptime Kairo
Back to Timeline
Remote

Matthew Green

@matthew_d_green@ioc.exchange
mastodon 4.7.0-alpha.2+glitch
  • Open on ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

17224 Followers
557 Following
36 Posts
Joined April 29, 2022
About me:
I teach cryptography at Johns Hopkins.

Posts

Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · May 06, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

There’s something ominous about the speed with which the entire world has marched to require identification on platforms and, as I expected, begin the process of banning anonymous VPNs.

169
15
136
1
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 25, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @fdlamotte@mamot.fr
@fdlamotte @marsik @tuga My big concern is that in public spaces you have to throttle or gate people accessing the thing. For broadcast (read) only that doesn’t matter but for writes I guess you’d need permissioning or throttling.
0
0
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
@fdlamotte @marsik @tuga I’m planning to prototype this next week just for fun, to see if it works. But curious if there have been any experiments in this model or if it’s a bad idea for known reasons. (I know iOS background BLE receiving is very very bad.)
0
0
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @fdlamotte@mamot.fr
@fdlamotte @marsik @tuga All of these projects seem to operate on a 1:1 PC/radio model. I think a better design would move the client logic to a PC/smartphone, but each radio device could support many clients — each with their own public key/identity. You’d have to use BLE advertisements to support many clients per radio.
0
2
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Boston. #meshcore
14
0
3
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
@marsik I’m planning to code this up next week.
1
1
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
@marsik oh never mind, I understand what you’re saying. What I want is that but bigger: I want a single radio to be able to support 100 simultaneous smartphone clients via BLE advertisements. For protests and natural disasters.
0
2
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 24, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @marsik@witter.cz
@marsik I think that’s basically what this does. It’s a real MeshCore node with all the radio layers turned into stdio ports. A better design would define this explicitly as a HAL.
0
1
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 23, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Right now it handles simulations that involve collisions, delays and other common events (in a very simple model). Each node is a simplified Meshcore node running as a process. #meshcore
6
1
2
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 23, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Just to give some visuals. #meshcore
3
2
1
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Mar 23, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

I’ve been working on a little simulator for MeshCore, written entirely using Claude Code. I was hoping some MeshCore devs might take a look and let me know if there are features they could use. https://github.com/matthewdgreen/meshcore_sim #meshcore

14
17
4
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Jan 23, 2026
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

Microsoft is handing over Bitlocker keys to law enforcement. https://www.forbes.com/sites/thomasbrewster/2026/01/22/microsoft-gave-fbi-keys-to-unlock-bitlocker-encrypted-data/

75
10
141
5
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 25, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

I was stupid enough to buy this new AppleCare One plan for a phone I bought my daughter. Now I learn this only covers the device if it’s connected to the same Apple ID (not family plan). Have to spend Christmas unwinding this and getting a refund, what a drag.

28
3
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Nov 13, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

@Aissen@social.treehouse.systems Inbound stuff like private inference.

1
0
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Nov 13, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

@Aissen@social.treehouse.systems It’s being discontinued for Chrome but they’re still using these tools internally I believe.

2
2
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Nov 13, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

@chris@mstdn.chrisalemany.ca That’s what they claim.

mstdn.chrisalemany.ca

Chris Alemany🇺🇦🇨🇦🇪🇸 (@chris@mstdn.chrisalemany.ca) - Alemany and Jensen Family Mastodon

2
1
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 10, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
And from a pure privacy perspective, the problem there is that once you’ve demanded every encrypted app add a scanning component, then changing what you scan for is just a software update to be agreed upon quietly in some committee down the line.
50
1
34
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 10, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
So what worries me come December is that we see a bunch of “moderated” proposals that preserve this central architectural change, but just use it for slightly less. That’s not going to save anyone.
23
2
6
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 10, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
The problem with this idea is that most “moderated” versions don’t solve the central problem: you’re changing private, encrypted messengers to have a component that scans the plaintext of the message. This is what potential makes your messages vulnerable to theft.
34
4
19
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 10, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

Germany has agreed to stop ChatControl for now, due to huge amounts of public pressure. Good job! The bad news is that it could come back as soon as December, and the German government has interpreted the feedback as a need to “moderate” the proposal.

128
5
113
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 02, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
A final note: it’s not totally clear what the UK is asking for here, but one theory is: they want access to foreign users who have ADP encryption on, but are on UK soil (for example, foreign diplomats.) This would be a technical nightmare, but it fits the facts. Would be a technical nightmare because now you’d have two versions of Apple encryption, where the security changes depending on where in the world you are (ie your IP address.) This is so dangerous that it’s tantamount to a global backdoor, including against US citizens.
26
3
17
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 02, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
As to question (1), the article isn’t super clear. But it’s worth pointing out that Apple doesn’t just provide end-to-end encryption for backups through their ADP feature. They also provide end-to-end encrypted backup for health data, web history and passwords, even without ADP. So “we want a backdoor to access iCloud encryption” could mean access to those password vaults and secure health data. This means Apple would have to disable those features in the UK as well, or deploy new insecure encryption code that could affect users globally. It’s also possible that the UK is asking for a backdoor in Apple’s iMessage text messaging system. That isn’t technically “iCloud” but it’s adjacent enough that I could see it getting presented that way. This would not be the first time the UK gov expressed interest in that. What’s worrying here is that the UK government seems absolutely determined to access user private data, no matter the bad press and the consequences. And they’re now willing to do it overtly. Between this and recent moves against encryption in the EU, we’re going to a bad place.
28
3
23
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 02, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
So here we are again. This time the UK is narrowly targeting their request at UK users only. But this is baffling for two reasons. First, Apple no longer offers the ADP encrypted backup feature to new UK users, and existing users are being migrated. So what is the UK asking for? Second, how is Apple supposed to make a single encryption system that’s secure for US users but not for UK users? This would require that they partition their software globally and have many versions, which seems like a disaster. Are you sure you’re running the “secure” OS?
20
3
6
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 02, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
For context: last year the UK demanded (in secret) that Apple create a backdoor into their iCloud Advanced Data Protection system. This was done via a Technical Capability Notice, and could have given the UK govt a master key to all iCloud users’ data worldwide. When this fact became public, it drew a huge backlash. Apple announced that it was entirely removing the encrypted backup feature for all UK users. Trump administration figures rebuked the UK government.
10
2
7
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 02, 2025
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

From yesterday: the UK is demanding another backdoor in Apple’s encryption. https://www.ft.com/content/d101fd62-14f9-4f51-beff-ea41e8794265?accessToken=zwAGQBl4pP6YkdPRAf1iFPlPUdO-_-pB6HlCZQ.MEYCIQDqJlwcbpQ4rrKlgeSJtbcTgqpW4uTX3yGMCHf2gdS0fQIhAMtU15LHqeHwAXTZ3wWJLDzI72kjsauSKc8OEDpim1Gx&sharetype=gift&token=3767767d-fe68-4911-a97e-c067715e061e

22
4
40
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Jul 19, 2024
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

How is the design of Crowdstrike not considered a massive security disaster to come? (Leaving aside today’s hiccup?)

54
9
17
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 20, 2023
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
I feel like we should introduce this to our CS students during their first year. “How to control the adoption rate of a feature based on where you place it in the Settings menu-tree.”
57
2
11
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 20, 2023
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Anytime someone sets a feature as a non-default, I assume 95% of users never touch it. When they put it under the “Privacy” settings menu, I raise my expectation to 99%. But Privacy -> Settings -> Advanced, wow. That’s like putting it in a disused lavatory in the basement of the town hall, with a sign that says “Beware of Tiger.”
102
8
53
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 20, 2023
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Ok the option to turn it off is tucked away under Privacy -> Advanced but it warns you that you might experience painful side-effects if you turn it on.
22
7
13
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Oct 20, 2023
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

I actually didn’t realize that Signal leaked my IP address to contacts when I initiated a call.

74
11
73
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Feb 20, 2023
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

Is there a ChatGPT IDE plugin that just adds comments to code?

31
9
12
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 20, 2022
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @baro77@ioc.exchange
@baro77 They said shared albums aren’t supported. As a special exception.
2
1
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 20, 2022
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @baro77@ioc.exchange
@baro77 Yeah looks like 16.2 and Ventura. And any devices that don’t support those newer updates have to be removed entirely. They can’t participate at all.
0
4
0
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 20, 2022
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
Also had to update a MacBook Air, which was messy. Even after the update ADP on my phone refused to acknowledge the Mac was up-to-date. Activating ADP on the Mac was possible, but failed mysteriously several times.
9
1
2
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 20, 2022
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange
Replying to @matthew_d_green@ioc.exchange
These criticisms are mostly UX nits, but I had to remove a bunch of old devices with names like “Matthew’s iPad (3)” that have probably been gathering dust in a closet. I think that’s ok but was a little nervous I might nuke a device my kids were using.
11
2
2
0
Open post
matthew_d_green
Matthew Green @matthew_d_green@ioc.exchange · Dec 20, 2022
Matthew Green
@matthew_d_green@ioc.exchange

I teach cryptography at Johns Hopkins. https://blog.cryptographyengineering.com (#matthew_d_green on the other site.)

ioc.exchange

Apple’s Advanced Data Protection isn’t too hard to activate, but the experience is a little clunky. Particularly the need to remove older devices from iCloud.

21
11
4
0

Remote instance

ioc.exchange
Open on original server

Media

313k7r1n3
Elektrine

Tor hidden service

elekhj7afj4qnrr4yd3bkzslsyo5jgfxw3orgjkhlcxifueodybyiiad.onion

Platform

  • Email
  • Chat
  • Timeline
  • Communities
  • VPN
  • DNS

Company

  • About
  • Contact
  • FAQ

Legal

  • Terms of Service
  • Privacy Policy
  • Warrant Canary
  • Lite (no JS)
  • VPN Policy
  • Source code

Support

  • support@elektrine.com
  • Report Security Issue
Mail client setup IMAP mail.elektrine.com:993 POP3 mail.elektrine.com:995 SMTP mail.elektrine.com:465
© 2026 Elektrine. All rights reserved. Server: 16:39:53 UTC