Comment by dominicgs | Hacker News Reader

Comment by dominicgs | Hacker News Reader

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I can't speak for OP, but my interest is in signal processing. DSP and FPGAs are a great match and with the boom in software defined radio, having reconfigurable DSP capabilities is extremely useful.

For example, if 802.11b devices had been built using FPGAs, an upgrade to 802.11g could have been an OTA update. Or a new Bluetooth variant emerges (e.g. BLE) and support could be added to computers and phones overnight.

For these applications it's useful to think of an FPGA as a chip that you can patch, upgrade or reconfigure for new applications. However, looking at it from another angle, we can think of it as software that isn't limited by the CPU architecture.

This second category opens up the possibility of crypto algorithms that don't suffer from the timing attacks that they do on the CPU. Or a video codec that can be designed without having to worry about which extensions the CPU supports.

I'm sure there are much better examples and some of these are bad ideas that would work better on a CPU, but hopefully that gives you some ideas.

I am replying to this comment instead of the multiple people under it.

You guys are right that FPGAs are not quite ready, or maybe will never be ready to be the primary radio for a phone because of the static power consumption. You could still have one available for certain burst operations that need to be highly accelerated. Good point about the timing attacks on crypto, but hardware crypto can be updated within an FPGA. This can be seen as a pro and a con to security.

SDR uses orders of magnitude more power than an ASIC implementation which is why no one uses them except for base stations -- such as cell towers.

FPGA based design for crypto would have the same timing attack as CPU. It can be worked around the same way it would for a CPU.

Sure, ASICs are always going to beat FPGAs and CPUs in power consumption for the same task, but there are also applications where the ability to update the system far outweigh the power requirements.

Interestingly, SDR is being used for the UK's small scale digital radio station trials this year. Off the shelf SDR hardware appears to be performing well enough at a lower cost than bespoke DAB hardware. Again, this fits in with your base station category.

You're right about timing attacks, I have no idea what I was thinking there. Would they be better for power analysis attacks? I guess if we're concerned about that then we'll end up back at ASICs again.

FPGAs ARE ASICs :) Just a special case of ASICs. The fabrication and processes are the same. There is no advantage of one over the other.

FPGAs are more vulnerable in some ways than ASICs because someone could steal your design and duplicate it much much more easily than an ASIC.

A lot of crypto chips have built in protection against many side-channel attacks.

Of course on the other hand FPGAs are not a great fit for mobile devices, which are one of the main consumers of wireless communication (radio) technology.

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