schizoidmanHead of the Signal app threatens to withdraw from Europe
earthwormSignal CEO Whittaker said that in the worst case scenario, they would work with partners and the community to see if they could find ways to circumvent these rules. Signal also did this when the app was blocked in Russia or Iran. “But ultimately, we would leave the market before we had to comply with dangerous laws like these.”
This is why we need the ability to sideload apps.
That means nothing when the servers stop taking EU traffic. I get your point, but the real solution here is putting a bullet (double tap) in Chat Control, once and for all.
That means nothing when the servers stop taking EU traffic
I don’t use any of these apps, so I’m not quite sure how they work. But couldn’t you just make an app that keeps a local private and public key pair. Then when you send a message (say via regular sms) it includes under the hood your public key. Then the receiver when they reply uses your public key to encrypt the message before sending to you?
Unless the sms infrastructure is going to attempt to detect and reject encrypted content, this seems like it can be achieved without relying on a server backend.
It is potentially doable:
A short message is 140 bytes of gsm7-bit packed characters (I.e. each character is translated to “ascii” format which only take up 7-bit space, which also is packed together forming unharmonic bytes), so we can probably get away with 160 characters per SMS.
According to crypto.stackexchange, a 2048-bit private key generates a base64 encoded public key of 392 characters.
That would mean 3 SMSs per person you send your public key to. For a 4096-bit private key, this accounts to 5 SMSs.
As key exchange only has to be sent once per contact it sounds totally doable.
After you sent your public key around, you should now be able to receive encrypted short messages from your contacts.
The output length of a ciphertext depends on the key size according to crypto.stackexchange and rfc8017. This means we have 256 bytes of ciphertext for each 2048-bit key encrypted plaintext message, and 512 bytes for 4096-bit keys. Translated into short messages, it would mean 2 or 4 SMSs for each text message respectively, a 1:2, or 1:4 ratio.
- NIST recommends abandoning 2048-bit keys by 2030 and use 3072-bit keys (probably a 1:3 ratio)
- average number of text messages sent per day and subscriber seems to be around 5-6 SMS globally, this excludes WhatsApp and Signal messages which seems to be more popular than SMS in many parts of the world [quotation needed, I just quickly googled it]
Hope you have a good SMS plan 😉
