Malleability of the blockchain's entropy

• Main Authors: Pierrot, Cécile, Wesolowski, Benjamin
• Other Authors: Centre National de la Recherche Scientifique (CNRS), Direction Générale de l'Armement, Direction Generale de l'Armement, ALgorithms for coMmunicAtion SecuriTY (ALMASTY), Laboratoire d'Informatique de Paris 6 (LIP6), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: Random number generation; Blockchain; Random Beacon; Bitcoin; Dyck language; [INFO.INFO-CR]Computer Science [cs]/Cryptography and Security [cs.CR]; Longyearbyen; Norway
• Online Access: https://hal.science/hal-01364045; https://hal.science/hal-01364045/document; https://hal.science/hal-01364045/file/paper.pdf

International audience Trustworthy generation of public random numbers is necessary for the security of many cryptographic applications. It was suggested to use the inherent unpredictability of blockchains as a source of public randomness. Entropy from the Bitcoin blockchain in particular has been used in lotteries and has been suggested for a number of other applications ranging from smart contracts to election auditing. In this Arcticle, we analyse this idea and show how an adversary could manipulate these random numbers, even with limited computational power and financial budget.