Cryptography and FPGA I see a lot of papers about FPGA implementations. For what kind of "concrete" application should we implement cryptographic algorithms on FPGA ? Which secured application require such a huge data processing performance ?
For what kind of "concrete" application should we implement cryptographic algorithms on FPGA? Which secured application require such a huge data processing performance ?


Well, FPGAs are ideal for a wide variety of applications, from high-volume applications to state-of-the-art products.

Imagine you are…


a bank, or 
a Big Data service provider, or 
a governmental institution, or 
a military force, or
…


and you need to encrypt terrabytes of data in the shortest amount of time possible, because…


time is money, or
your clients want their Big Data to be stored safely on your servers via a double-encryption, or
a huge stream of intercepted metadata needs to be protected from the public eye, or
the enemy is near your last line of defense and you need to secure some data immediately, or
…


Whatever valid reason you might have to need cryptography “now” instead of “later”, you will want to choose the fastest option possible. In that case, it makes sense to use the (immensely) faster FPGA (and/or ASIC) solutions instead of hoping your CPU(s) will manage to handle the job in such a short amount of time.

From a civilian point of view, I guess the most understandable motivation as to why cryptographic algorithms are implemented on FPGA would be the economic factor. It should be noted that you burn less energy when using an optimized FPGA or ASIC implementation. This practically means you can “produce more work” while investing the same (or less) amount power as you would have invested when using your CPU(s). 

Now, related to your comment:


  Are there non cryptanalytical examples ?


Thinking about it, here’s a first, nice, practical, non-cryptanalytical example: cryptocurrencies. Just take a short look at the history of those folks… who evolved from “mining their coins” (read: creating their proof of work via cryptographically secure hashing algorithms) with CPUs, then switched over to GPUs because they were faster and more energy efficient, and ended up using specialized ASICs.

Besides that, there are – of course – other non-cryptanalytical examples. As a matter a fact, “An FPGA Implementation and Performance Evaluation of the. AES Block Cipher Candidate Algorithm Finalists” already hints at that, and a short search engine quest would have provided you with ample commercial product examples.

For your convenience, here are two randomly picked, non-cryptanalytical product ranges:


Helion : IP Core Products, based on ASIC or FPGA (Encryption, Authentication, Hashing, et al.)
Nallatech : 40Gbit AES Encryption Using OpenCL and FPGAs


I’m sure you’ll be able to find more examples using your favorite search engine…



EDIT (Lazy-Friday Bonus):

For the fun of it (and because I had a lazy friday afternoon), I whipped up two non-optimized C proggies just to show you something practical…



See that speed (and hash-count) difference? 

Now imagine the increase that could be gained when using a field programmable gate array (FPGA). What might take years for one person, might just be a matter of hours for another.

Such speed differences are like a coin with two sides: benign users can enhance security in many areas, while malign users can attack faster (making some attacks feasable in the first place.)

That’s one of the reasons cryptographical FPGA solutions are of interest… no matter which side of the coin one prefers or chooses.