Record Evidence

Create a permanent,
tamper-evident record.

Drop any file. ProofLedger computes its SHA-256 fingerprint locally and anchors it to Polygon and Bitcoin — creating an immutable timestamp before disputes arise.

File never leaves your device · Hash computed locally · Verifiable forever

What gets recorded

Three things. Only three things.

ProofLedger records the minimum necessary to establish existence, integrity, and timing. Nothing else.

SHA-256 Fingerprint

The cryptographic fingerprint of your file's exact byte content at the moment of recording. Identical files always produce the same hash. A single altered bit produces a completely different one.

File content is never uploaded or stored

Blockchain Timestamp

The block number, transaction ID, and UTC timestamp at which the fingerprint was anchored. Polygon confirmation is near-instant. Bitcoin adds an immutable second layer via proof-of-work and Merkle inclusion.

Timestamps cannot be altered retroactively

Signed Certificate

A human-readable PDF signed with Ed25519, containing the Proof ID, hash, chain anchors, and independent verification instructions. Designed to stand up under adversarial review.

Verification works without ProofLedger's servers

Your file never leaves your device.

All SHA-256 hashing happens in your browser using the Web Crypto API (crypto.subtle.digest). The file bytes are processed entirely in local memory and never transmitted to ProofLedger's servers. Only the 64-character hex fingerprint is sent — a one-way transformation that cannot be reversed to recover the original file. This is architecturally enforced, not a policy promise.

Reference

Pre-loss temporal authority documentation is the practice of recording evidence at the moment of creation, cryptographically fixing its state in time before disputes, incentives, or claims exist. These systems establish when a record existed and what state it was in using repeatable, tamper-evident procedures that allow independent verification without reliance on the recording system itself.

ProofLedger is an implementation of this approach, designed for high-liability environments where contemporaneous, pre-loss records must remain verifiable long after they are created.