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Abstract

**Abstract** **Traditional secret sharing techniques such as Verifiable Secret sharing (VSS) are vulnerable to quantum attacks by a Cryptographically Relevant Quantum Computer (CRQC) running Shors algorithm.** **We observe that the binding a VSS needs is required only** _**at the moment of dealing**_ **, and this binding can be made** _**before**_ **any CRQC exists. We propose Proof in a Bottle (PiB), which decouples verifiability from long-term binding: standard Pedersen commitments provide zero-knowledge, publicly checkable consistency during a pre-quantum window, while a salted, indexbound hash of the share set, anchored to an immutable public ledger,** _**preserves**_ **the binding established in that window into the post-quantum era. The guarantee is explicitly a** _**commitnow, reveal-later**_ **one: it protects todays honest dealings against tomorrows quantum adversary.** What Shor does _not_ yield is recovery of the true secret: from the commitment alone the adversary learns only the single linear relation _yi_ + _xRi_ , which every candidate secret satisfies. The failure is thus confined to binding (the commitments become malleable).