FALCON is designed with the intention of providing small public key and signature sizes in order to better facilitate the transition to post-quantum schemes [ISBN 978-3-030-57681-3, page 31]. This property is particularly relevant in the field of IoT or vehicle construction. In real-time systems, minimal delays are important, which is why large signatures are avoided.
Falcon 512 bit and Dilithium II are the fastest algorithms for verifying signatures, right after Rainbow. However, Rainbow is uncertain and not a finalist. [page 6]. Verifying the signature is more important than generating it in the blockchain area, since the transactions are confirmed by a large number of miners in the network. The generation of the signature is therefore only pushed once, while the verification of the signature runs through thousands of iterations.
In the future, addresses with 1024 bits will also be offered. Falcon uses a Fourier transform to create the signature. So the frequency spectrum is shown. This approach is good because security increases greatly when going from 512-bit to 1024-bit without significantly increasing the time required to verify the signature. In one attempt, checking the signature for FALCON 1024 required 0.001 ms longer than was required for FALCON 512 bit. A FALCON 1024-bit signature enables the highest possible security class (class 5 / 5) and was still checked the fastest of all tested quantum-safe signatures. [ISBN 978-3-030-57681-3 page 3] [page 6]