Séminaire Algorithmique : Michel Seck (Ecole Politech. Thiès, Sénégal) « Towards post-quantum Bitcoin blockchain using Dilithium signature »

Bitcoin is one of the famous cryptocurrencies in the world. It is a permissionless blockchain, and all transactions are stored in a public decentralized ledger. In its security design, Bitcoin utilizes various cryptographic primitives, such as hash functions and signature schemes. In the current version of Bitcoin, the Elliptic Curve Digital Signature Algorithm (ECDSA) is employed, which is not considered post-quantum secure due to the Shor’s algorithm. In this talk, we will analyze the potential replacement of ECDSA with Dilithium, which is a postquantum digital signature based on lattices and recently standardized by NIST as ML-DSA. Bitcoin operates on a pseudonymous system rather than providing complete anonymity. To enhance privacy protection, the Bitcoin community has adopted a special type of deterministic wallet as outlined in Bitcoin Improvement Proposal 32 (BIP32). We will show how to construct deterministic wallets from Dilithium by first designing DilithiumRK, a signature scheme with rerandomizable keys build on top of Dilithium. We will then discuss the unlinkability, unforgeability and efficiency of DilithiumRK and the resulting wallets.