Facts
Blockciphers are used to build encryption algorithms and compression functions for hash algorithms.
(Unkeyed) Permutations are also complementing blockciphers in encryption and hashing.
Large block sizes are preferred.
But There are embedded/IoT/lightweight systems.
There are still mode of operations defined for 64-bit blocks AND there are still 64-bit blockciphers with key lengths that're considered secure (e.g. IDEA).
My question
Are blockciphers with 64-bit blocks still relevant?
Age-old update:
Is this a dupe of that or vice versa?