Independent This document defines WebProof, a new protocol layer for the World Wide Web that enables any web resource, document, dataset, media artifact, or AI-generated output to be cryptographically proven to exist in a specific form, at a specific time, under a specific author's custody. The web currently provides transport security (TLS), naming (DNS), and resource identification (URI/URL), but no native mechanism for verifiable provenance. Any web resource can be silently modified, backdated, or repudiated. WebProof fills this gap by defining a dual-anchored provenance layer that combines DOI-based archival permanence with blockchain timestamping to produce a WebProof Record (WPR): a machine-readable, independently verifiable proof of a resource's existence, integrity, authorship, and timestamp. WebProof introduces a well-known URI (/.well-known/webproof) for resource-level proof publication, HTTP response header extensions for inline provenance signaling, a canonical WebProof Record schema, a generation and verification procedure, and a DNS TXT record profile for domain-level WebProof registration. WebProof is designed to compose with existing web infrastructure and is intentionally non-disruptive: it does not require modifications to HTTP, TLS, or DNS to function, operating as an opt-in provenance layer that any web publisher can adopt independently. The protocol builds on the Dual-Layer Digital Permanence methodology introduced by Lawrence John Reilly Jr. in the Reilly EternaMark (REM) Protocol [I-D.draft-reilly-rem-protocol]. The term "WebProof" is coined by Lawrence John Reilly Jr. and first formally defined in this document. This revision adds material to draft-reilly-webproof-00 without removing or altering any text carried forward from it. The additions are summarized in Section 18.