ER Diagram for an Image Steganography Project

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An ER diagram for an image steganography project usually models a small set of persistent entities: a user or actor, the image file that carries hidden data, the logical payload being hidden, a carrier record that links a payload to a specific image and settings, an extraction or reveal job, and an audit entry for the operation. In a simplified design, the relationships centre on one statement: a user can create many payloads, a payload can be embedded into many carrier images, one carrier image usually holds one embedded payload in a given operation, and every embed or extract operation can produce audit history.

The diagram is a database and workflow model, not a mathematical description of the steganographic algorithm itself. It describes which records are stored and how they relate; it does not itself prove payload capacity, visual imperceptibility or resistance to steganalysis.

Entity relationship overview

A compact ER model for a typical image steganography system can be described with six core entities. A user is the actor who starts an embedding or extraction task. An image is the cover file, and it may later become a stego image after data has been embedded. A payload is the secret message or file before embedding. A carrier or stego record represents the association created when a payload is hidden in an image. An extraction task records the attempt to recover a hidden payload from a provided image. An audit log records each operation and its result.

Entities and likely attributes

The attributes below are a common starting point. The supplied project evidence does not provide a fixed schema, so field names and data types should be treated as design suggestions rather than documented measurements.

Entity	Example attributes
User	user id, name, role, created at
Image	image id, file name, format, width, height, file size, checksum, uploaded at
Payload	payload id, original file name, file size, checksum, payload type
Carrier	carrier id, image id, payload id, method, key reference, created at
Extraction task	extraction id, carrier id or image id, requested by, status, requested at
Audit log	audit id, user id, operation, related record id, result, logged at

Cardinality in the relationships

A user may create zero or more images and payloads, while a created image or payload belongs to one user in a simple model. A payload may be related to one or more carrier records if the same secret is embedded into several images. Each carrier record references exactly one image and one payload for that particular embedding operation. If the project also supports multiple hidden objects in one image, the carrier relationship would need to become many-to-many between images and payloads, with the carrier serving as the junction record.

An extraction task may reference a carrier record when the intended hidden object is known, or an image alone when the system must attempt recovery without that link. Each extraction can create one or more audit entries, but the minimum useful model keeps one audit entry per finished operation.

Alternative minimal ER diagram

If the project does not need per-user creation records, the model can be reduced to four entities. An image stores the cover or stego file. A secret payload stores the message to hide. An embedding record connects one image with one payload and stores the method and settings used. A recovery record stores the attempt to extract data and its resulting status.

In this reduced form, image and payload are related through embedding, and recovery may reference the embedding record. Audit history is optional, but keeping at least a recovery status field helps distinguish a hidden payload from a failed or misconfigured extraction attempt.

What an ER diagram does not capture

The diagram normally records that a payload was associated with an image using a named method. It does not define the bit changes made by that method, the image format constraints used for embedding, the maximum safe payload size, or whether the resulting stego image looks natural to a viewer. Visual similarity and resistance to steganalysis are also separate concepts: a message can look visually identical in a side-by-side view and still be detectable by statistical analysis.

Likewise, steganography hides the presence of data, while encryption changes the readable form of data that may still be visible as ciphertext. An ER field labelled method does not automatically describe either property.

Evidence gaps

The supplied material does not include a reference ER diagram, a defined database schema, a chosen image format or an implemented extraction workflow. Therefore this article describes the likely model and optional simplifications without claiming that any specific project uses these exact table names, constraints or attribute types.