An interactive demonstration of the timing side-channel that has repeatedly threatened HQC (Hamming Quasi-Cyclic), the code-based key-encapsulation mechanism NIST selected for standardisation in 2025.

A substitution cipher is a cipher that maps each symbol in the plaintext to a symbol according to a permutation of the alphabet. A breakpoint is a location in the ciphertext where the cipher changes.

A ciphertext-only attack is a type of cryptanalysis where the attacker only has access to the encrypted message and tries to recover the original plaintext or the key used to encrypt it. This is one ...