Date de l'exposé : 11 janvier 2019 salle Guernesey à l'ISTIC
Wave: A New Code-Based Signature Scheme
It is a long standing open problem to build an efficient and secure digital signature scheme based on the hardness of decoding a linear code which could compete with widespread schemes like DSA or RSA. The latter signature schemes are broken by a quantum computer with Shor’s algorithm. Code-based schemes could provide a valid quantum resistant replacement. We present here Wave the first « hash-and-sign » code-based signature scheme which strictly follows the GPV strategy which ensures universal unforgeability. It uses the family of ternary generalized $(U,U+V)$ codes. Our algorithm produces uniformly distributed signatures through a suitable rejection sampling (one rejection every 3 or 4 signatures). Furthermore, our scheme enjoys efficient signature and verification algorithms. For 128 bits of classical security, signatures are 8 thousand bits long and the public key is smaller than one megabyte.