Explore quantum-access security in this 25-minute conference talk from the ITC Conference 2021. Delve into the analysis of the Winternitz One-Time Signature Scheme in the quantum random oracle model. Learn about the gap-filling approach to the Lamport one-time signature scheme's security analysis and its generalization to the Winternitz OTS. Discover a new tool for analyzing hash chains in the QROM based on Zhandry's superposition oracle technique. Gain insights into digital signature schemes, quantum computing, blind-unforgeability, and the limitations of standard security notions in the quantum era. Understand key generation, signature encoding, and verification processes in the context of quantum-access security.