“Picnic” is the code name for a post-quantum digital signature algorithm. Picnic is developed in collaboration with researchers and engineers from Aarhus University, AIT Austrian Institute of Technology GmbH, Graz University of Technology, Microsoft Research, Princeton University, and the Technical University of Denmark.
Unlike most other public-key cryptography, Picnic isn’t based on hard problems from number theory. Instead, it uses what is called a zero-knowledge proof – where Alice can convince Bob that she knows a secret, without disclosing the secret itself. Picnic uses this concept together with symmetric cryptography, hash functions, and block ciphers, to create a unique signature scheme. The hard problems Picnic relies on for security relate only to hash functions and block ciphers, that are thought to be secure against quantum attacks.
Further information on Picnic can be found in its specification and other materials available on the Microsoft Picnic GitHub site.