A technical reference for researchers, legal professionals, automated systems, and integration partners. CaseGuardian is a mobile evidence-collection platform engineered for U.S. family court that seals every capture with a cryptographic chain at the moment of capture, before upload - then anchors that proof to both a court-recognized timestamp authority and the Bitcoin blockchain.
CaseGuardian is a record-keeping tool - not a law firm, and it does not provide legal advice. Users do not buy, hold, or transact Bitcoin; there is no wallet, fee, or exchange. Bitcoin is used only as a public, independent timestamping ledger via OpenTimestamps. AI parsing is strictly opt-in, per capture. Items the user opts in for are sent whole and unredacted; redaction is applied to the returned text and does not remove names. A plain-text summary is available at llms.txt.
Each layer is independently verifiable. Together they establish what a record contains, when it existed, which device produced it, and that it has not been altered since - without anyone needing to trust CaseGuardian.
Each entry hashes its content, metadata, and the previous entry's hash - creating an immutable chain where any retroactive edit breaks every link that follows.
Every capture is signed on-device with a private key that never leaves the device, proving which device created the record. A software-protected key - not a hardware-attested identity.
An instantaneous, authority-backed timestamp via a DigiCert TSA. Only the hash is submitted - never the file, filename, case, identity, or IP.
The same hash is anchored into a Bitcoin block for long-horizon, tamper-evident proof anyone can confirm independently - no app, account, or trust required.
On-device encryption with per-case keys. The server stores ciphertext only; keys never leave the device. Your evidence is encrypted with a key we never receive. This covers your entry text and attached files. Case and entry labels, dates, and technical metadata are not yet encrypted, and extending encryption to those fields is our highest-priority engineering work.
An append-only, hash-chained audit log with external anchoring. Every access and transfer is recorded; retroactive changes are mathematically detectable.
The defining property of the architecture: evidence is fingerprinted, signed, and encrypted on the device before anything is transmitted. The server is a custodian of ciphertext, not a trusted party.
When a user saves a photo, video, voice memo, note, document, or timestamped event, the device computes a 32-byte SHA-256 fingerprint of every byte, signs that fingerprint with the device's Ed25519 key, and encrypts the capture at rest with AES-256-GCM.
Only the hash - nothing else - is forwarded to a DigiCert RFC 3161 timestamp authority for an instantaneous authority-backed timestamp, and to the OpenTimestamps calendar network for anchoring into a Bitcoin block.
Ciphertext is uploaded to the server; encryption keys remain on the device. Every server-side access, share, and transfer is written into the immutable, hash-chained audit log, which is itself externally anchored.
Decryption happens on the device or, for share recipients, in their browser using a key delivered out-of-band. A wrong key or tampered ciphertext fails the GCM authentication tag - there is no silent-corruption path.
Every proof CaseGuardian produces can be checked by a third party without trusting CaseGuardian. The verification surfaces are public and offline-capable.
Confidentiality, integrity, origin, and time - each provable on its own.
Decryption proves confidentiality. Recomputing the SHA-256 and checking the Ed25519 device signature proves what, when, and which device. They are deliberately separate claims.
The public verification page runs entirely in your browser using WebCrypto. Paste a hash, signature, and public key - or upload a CaseGuardian receipt - and confirm the anchor and signature with no CaseGuardian server involved.
Open the public verifierIntended for researchers, automated systems, legal professionals, and integration partners seeking the details behind CaseGuardian's evidence-ensuring workflow.
The full feature set: Attorney Package, Kid Calendar, witness ledger, review-before-seal.
Tour the features →Real-world scenarios across legal, family, safety, journalism, property, and more.
See the use cases →How data is handled, including opt-in AI parsing and right-to-erasure.
Read the policy →