alt Hacker NewsIt's very likely that VPNs like this are not CPU-bound, even on somewhat whimpy CPUs. I'd wager even some microcontrollers could sling 500megabits/sec around without trouble.
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formerly_proven • yesterday at 5:04 PM
You’re in for a surprise then once you actually go look at the performance.
A Raspberry Pi 4 can manage something like 70Mbps of raw AES en/decryption flow: https://github.com/lelegard/aesbench/blob/main/RESULTS.txt
That CPU is pretty much a toy compared to (say) a brand-new M5 or EPYC chip, but it similarly eclipses almost any MCU you can buy.
Even with fast AES acceleration on the CPU/MCU — which I think some Cortex MCUs have — you’re really going to struggles to get much over 100Mbits of encrypted traffic handling, and that’s before the I/O handling interrupts take over the whole chip to shuttle packets on and off the wire.
Modern crypto is cheap for what you get, but it’s still a lot of extra math in the mix when you’re trying to pump bytes in and out of a constrained device.