PQClean has a correctness error in HQC decapsulation
A correctness error has been identified in the reference implementation of the HQC key encapsulation mechanism. Due to an indexing error, part of the secret key is incorrectly treated as non-secret data. This results in an incorrect shared secret value being returned when the decapsulation function is called with a malformed ciphertext. No concrete attack exploiting the error has been identified at this point. However, the error involves mishandling of …