Pro Tier Module

Evidence Custody + File-Hash Integrity

Fingerprint digital evidence with SHA-256 and build a chain-of-custody log, entirely in the browser.

See it run - a worked example, 100% in this browser tab

The problem

Digital forensics needs a tamper-evident fingerprint bound to a custody record, but uploading evidence to a cloud service to hash it can break the very integrity the record is meant to prove.

The local-first solution

A deterministic, client-side tool computes the SHA-256 digest with WebCrypto and assembles a custody log that binds who handled the item to an exact fingerprint of what was handled, with the evidence never leaving the browser.

What it does

SHA-256 (FIPS 180-4) hex digest computed in-browser via WebCrypto

Constant-time verify of an expected hash against the computed one

Chain-of-custody log: date/time, custodian, action, location, notes

Custody record binds the SHA-256 to the evidence

Exportable, consistently formatted log

Legacy MD5/SHA-1 offered only to match a legacy tool, labeled as weak

Honest scope

SHA-256 is tamper-evident, not tamper-proof, and re-hashing an altered file just fingerprints the altered bytes. This is not a notarization, digital signature, or timestamp authority; it records what you enter and does not attest date, identity, or lawful acquisition. Pair it with an RFC 3161 timestamp or verified acquisition image.

Authorities cited

FIPS PUB 180-4 (Secure Hash Standard) - SHA-256 (and SHA-1) specification. NIST, August 2015.
W3C Web Cryptography API - SubtleCrypto.digest() computes the SHA-256 digest in-browser (no upload).
NIST SP 800-86 - Guide to Integrating Forensic Techniques into Incident Response: hashing acquired data verifies integrity (a matching hash shows the data was not altered).
NIST SP 800-101r1 - Guidelines on Mobile Device Forensics: chain of custody documents seizure, custody, control, transfer, and disposition of evidence.
SWGDE Best Practices for Computer Forensic Acquisitions - acquisition images are hash-verified; document the chain of custody.
RFC 3161 - Time-Stamp Protocol (a trusted timestamp authority; NOT provided here - pair it with this fingerprint for binding time attestation).
NOTE: SHA-1 / MD5 have known collisions and are DEPRECATED for integrity (offered only to match a legacy tool's output - prefer SHA-256). MD5 is not provided via WebCrypto.

Hash and log the evidence

Compute the digest and build the custody log in your browser, then attach the record to a Worklog case or share it through a Gate client portal. The evidence bytes are never uploaded to anyone's cloud.

Try it live inside GDBS Open a free Standard account

GDBS by VaultSync Solutions Inc. - Verifiable Computation. gdbs.getvaultsync.com