(registered 2025-04-18, last updated 2025-04-18)

Media type name: image

Media subtype name: vnd.blockfact.facti

Required parameters:

content-type (string):

Description: Specifies the MIME type of the wrapped image file.
Examples: image/jpeg, image/png.
Purpose: Enables systems to interpret the underlying content accurately.

version (string):

Description: Indicates the version of the .facti container format.
Example: version=1.0.
Purpose: Ensures compatibility and correct processing of files using different container versions.

blockchain-id (string):

Description: Provides the unique blockchain transaction or smart contract identifier for verifying the file.
Example: blockchain-id=0x123abc456.
Purpose: Ensures integrity and verification via a blockchain-based system.

checksum (string):

Description: A hash value (e.g., SHA256) to verify the integrity of the contained file.
Example: checksum=abc123hash.
Purpose: Detects data corruption or unauthorized modifications.

encryption-key (string):

Description: Specifies the key or key identifier used for decrypting the file content or metadata.
Example: encryption-key=key-id-789.
Purpose: Enables secure decryption of encrypted components of the .facti file.

Optional parameters:

encryption (string, optional): Describes the encryption applied to the metadata (e.g., AES256).

compression (boolean, optional): Specifies if compression is applied to the wrapped content (true or false).

Structure and Fields:

* author (string, optional): The name or identifier of the image creator.

* creation_date (ISO 8601 string, optional): The timestamp of when the image was originally created.

* location (object, optional): Contains latitude and longitude fields to indicate where the image was captured (if geotagging is enabled).

* tags (array, optional): A list of keywords or labels associated with the image.

* description (string, optional): A textual description of the image.

This JSON structure ensures extensibility while maintaining readability for applications processing .facti files.

Encoding considerations: binary

Security considerations: The .facti file includes encrypted metadata that can be decrypted for verification purposes using an external BlockFact application.

The metadata contains a unique ID and other file integrity information, verified via a blockchain-based system.

The use of encryption ensures privacy and protects against unauthorized modification.

Systems handling .facti files must ensure the integrity of both the metadata and the wrapped image format.

Interoperability considerations: Lite systems can decode and access the wrapped image content without requiring decryption of the metadata.

Full systems can decode both the image content and the encrypted metadata to verify the unique ID and file integrity via the blockchain.

Developers should ensure systems recognize and support .facti extensions for seamless integration.

Published specification: The .facti format specification is available at https://blockfact.io/specifications/facti.txt

Applications which use this media:

BlockFact Verification Tool (desktop, web, and mobile apps)
BlockFact Creation Tool (desktop, web, and mobile apps)
Blockchain-integrated content management systems (CMS)
Digital asset management (DAM) platforms

Fragment identifier considerations: N/A

Restrictions on usage:

Prohibited Uses

The .facti format is designed for secure image verification and integrity protection. It should not be used in the following environments due to potential security risks or interoperability issues:

Insecure Transport Protocols (HTTP, FTP, etc.)
* .facti files should be transmitted over secure channels (e.g., HTTPS, encrypted storage) to prevent unauthorized interception or metadata leakage.

Non-Compliant Decoding Systems
* Applications that do not support structured metadata or cryptographic verification may fail to process .facti files correctly.

Metadata-Stripping File Systems
* Legacy storage environments (e.g., FAT32) may strip embedded metadata, reducing verification capabilities.

Automated Modification Pipelines
* Systems that alter or re-encode .facti files without preserving integrity mechanisms may invalidate verification properties.

Offline-Only Environments Without Blockchain Access
* Some verification features require a blockchain connection; offline-only systems may not fully validate .facti files.

Additional information:

1. Deprecated alias names for this type: none
2. Magic number(s): 0xFA I1 01 00
3. File extension(s): .facti
4. Macintosh file type code: FACTI
5. Object Identifiers: pending assignment

File Structure:

A .facti file consists of the following components:

1) Magic Number: Identifies .facti files uniquely.

Value: 0xFA I1 01 00

2) Required Parameters: (Used to ensure compatibility)

version (string, required): Specifies the .facti format version (e.g., 1.0).

3) Optional Parameters: (May be included based on implementation)

encryption (string, optional): Specifies the encryption type for metadata (e.g., AES256).
compression (boolean, optional): Indicates whether the image content is compressed (true/false).

4) Encrypted Metadata: Contains additional data for verification and offline access.
This metadata is typically stored on-chain, but an optional local copy may exist within the .facti file.
Systems should prioritize verifying metadata against the blockchain.

5) Image Content: The wrapped standard image format (e.g., .jpeg, .png).

Person to contact for further information:

1. Name: Egbert von Frankenberg
2. Email: egbert&blockfact.io

Intended usage: COMMON

The .facti file type is designed for secure and verifiable image distribution across systems that require both interoperability and blockchain-based verification.

Author/Change controller: Egbert von Frankenberg