[grishka]

Native TLS is the most impressive part.

I remember being told that modern cryptography isn't usable on old CPUs simply because of the amount of unoptimizable number crunching involved. As in, some steps of the key exchange algorithm would take so long that the server would time out. But apparently that's not a problem for a 386 despite being old and slow?

[Shawnj2]

Considering how many embedded devices are in use, a lot of which are 8 bit microcontrollers with minimal RAM, designing systems that way would be irresponsible. There probably are some systems that don’t have an embedded use case that would (Eg. Encryption for live video) but not everyone is connecting to the internet on the newest iPhone.

[kjs3]

One of the specific design requirements for the AES competition is that it could be used in embedded systems, which at the time was synonymous with 8-bits and limited memory. There are AES candidate 'reference' implementation floating around for the original AES bakeoff (that Rijndael eventually won) running in a couple of KB of memory for the 8051 and mc6805, for example, and I know of at least one PIC version of AES in use. There's probably tons of other examples; given how well documented the algorithm is, it's one of those things a lot of people probably take a swing at.

Now...this is obviously for sending small amounts of data at low (very) bit rates 'securely', not modern web or streaming or anything fun like that. And my understanding is that the real killer in trying to do something like TLS on such small platforms is the key generation/exchange/management part. YMMV.

[grishka]

I've always had the impression that modern internet-connected (and I mean the public internet with TLS and all that, not just LAN) embedded devices use fairly beefy, and at least 32-bit, CPUs just for that reason. But the bits don't make as much difference as the clock speed, and that can go much higher in modern days thanks to the smaller node size.

[Shawnj2]

In 2023 yes but there are lot of in production systems designed in the past around older chip designs and old hardware in the real world with slower chips. For example a common low processing power network device you can still make easily today is an Arduino Uno with a network hat.

[nick__m]

the network "hat" use to be a full blown ESP8266, an mcu that is a lot more powerful than the arduino Uno !

[grishka]

Are you sure an Arduino has enough resources to establish a TLS 1.3 connection?

[kjs3]

There are "100 MIPS" 8051 variants (for some value of MIPS) like the Silicon Labs C8051F360. Not sure that's fast enough for 'modern web', but probably fast enough for a lot of interesting things.