FALCON

FALCON is a lattice-based digital signature algorithm, standardized by NIST in 2024 alongside Dilithium and SPHINCS+ under the name FN-DSA, with full finalization expected after Dilithium and SPHINCS+. Like Dilithium, it relies on structured lattice problems (NTRU lattices specifically) rather than hash functions, but its design produces meaningfully smaller signatures than Dilithium's, closer to the sizes classical ECDSA users are used to. That compactness makes FALCON the candidate of choice for bandwidth- or storage-constrained deployments, such as smart cards, IoT devices, or systems issuing very large volumes of certificates, where Dilithium's larger signatures are a real operational cost. The tradeoff is implementation complexity: FALCON's signing algorithm depends on floating-point arithmetic and is considerably harder to implement correctly and securely (specifically, without leaking timing side-channels) than Dilithium's, which is one reason NIST recommends Dilithium as the general-purpose default and FALCON for size-sensitive cases specifically.