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SIGNOS_SEAL_V2 — Field Reference

This document describes the data fields embedded in Signos-sealed media files. It is descriptive, not prescriptive — it tells you what is there, not why.

1. Magic prefix

All Signos seal payloads in image files begin with the literal ASCII bytes:

SIGNOS_SEAL_V2:

followed immediately by a UTF-8 encoded JSON object.

Video files do not use a magic prefix; they use a named QuickTime metadata key (see §3).

2. Image embedding

File type Primary location Fallback location
JPEG, HEIC, PNG, TIFF, WebP EXIF UserComment TIFF ImageDescription

The full payload is SIGNOS_SEAL_V2: + JSON object.

3. Video embedding

File type Primary location Fallback location
MP4, MOV moov/meta/keys + ilst, key com.signos.seal in namespace mdta moov/udta/com.signos.seal (flat key+JSON, legacy)

Video payloads are the JSON object only (no SIGNOS_SEAL_V2: prefix).

4. Size limit

JSON payload (after any prefix): maximum 65,536 bytes (64 KB).

5. JSON fields

Required

Field Type Notes
version string Schema version, e.g. "SIGNOS_SEAL_V2"
blockchainNetwork string Network identifier, e.g. "mainnet", "testnet"
verifyUrls array of string Public Algorand node/indexer endpoints
verificationInstructions string Human-readable description of how to verify

Content fields

Field Type Validation
originalHash string 64 hexadecimal characters (BLAKE3-256). Optional.
sealedHash string 64 hexadecimal characters (BLAKE3-256). Optional.
hashAlgorithm string Algorithm name, e.g. "BLAKE3"
strategy string Embedding-strategy identifier
strippingAlgorithm string One of SIGNOS_STRIP_V1, SIGNOS_STRIP_IOS_V1. Forward-compatible: unknown identifiers warn but do not fail.
createdAt string ISO 8601 timestamp

Attribution fields (all optional)

Field Type Validation
creator string Free-form
description string Free-form
license string Free-form (e.g. "CC-BY-4.0", "All rights reserved")
aiTrainingPermission string Free-form opt-in/out marker
gpsLatitude number Decimal degrees, -90 to 90
gpsLongitude number Decimal degrees, -180 to 180

Human-presence fields (all optional)

Field Type Validation
motionHash string 64 hex characters (BLAKE3-256)
motionConfidence number 0 to 1
biometricMethod string Method identifier
motionSamples array of object See §6
authToShutterInterval number Seconds
biometricDomainStateHash string 64 hex characters (BLAKE3-256)

Blockchain reference fields (all optional)

Field Type Validation
publicTransactionId string 52 characters from [A-Z2-7] (Algorand transaction identifier, base32)
walletAddress string 58 characters from [A-Z2-7] (Algorand address, base32)
verifyWalletUrl string URL

A field with a present-but-malformed value is dropped on parse rather than failing the whole record (best-effort).

6. motionSamples element shape

Each entry in the motionSamples array has the form:

Field Type Description
t number Timestamp offset (seconds from capture start)
x number Acceleration on X axis (g-force)
y number Acceleration on Y axis (g-force)
z number Acceleration on Z axis (g-force)
rx number (optional) Rotation rate on X axis (radians/second)
ry number (optional) Rotation rate on Y axis (radians/second)
rz number (optional) Rotation rate on Z axis (radians/second)

7. Algorand transaction note

The transaction note attached to on-chain registrations is a separate JSON object (not embedded in the file). It uses the following keys:

Field Type Validation
version string
sealed_hash string 64 hex characters (BLAKE3-256)
original_hash string 64 hex characters (BLAKE3-256). Optional.
motion_hash string 64 hex characters (BLAKE3-256). Optional.
creator string Optional
license string Optional

The Algorand network limits transaction notes to 1024 bytes total.

8. Reference verifier

The official verification implementation is open source: Signos-app/verify.

Live demo: verify.signos.app.

Read the source for the exact extraction, hashing, and on-chain lookup workflow.

9. Versioning

This document describes SIGNOS_SEAL_V2. Future revisions will bump the magic prefix and key namespace.

10. License

This specification text is licensed under Creative Commons Attribution 4.0 International (CC-BY-4.0). © 2026 Signos LLC.

The Signos architecture is patent-pending; this document covers only the embedded field format.