What You Can Do with a Piculum

A Picture Full of Data

A piculum is an ordinary PNG image that is also a container. You look at it and see a picture. Someone with the right password opens the same file in a piculum decoder and gets content back out of it: a message, a filled-in record, a file. The picture is real, the content is real, and they travel together in one file that behaves like any other image.

That alone is useful - an encrypted zip looks like an encrypted zip, but a piculum just looks like a picture, and it goes everywhere a picture goes. The deeper power, though, is not the carrying. It is the designing.

The Real Power: You Design the Data, Others Fill It

A piculum is a designed object, and the design has two deliberately separated sides:

The piculum designer decides what the thing is. They paint the regions, and they declare what each region holds: this one is a date, this one is a name, this one is a phone number, this one is a choice from a fixed list, this one is free text, this one carries a file. Each field gets a caption, a place, and a measured capacity. What the designer has built, in plain terms, is a data dictionary - a definition of a record - that happens to wear a picture.

The data person - a customer, a family member, a coworker, or a program - never sees any of that machinery. They open the template and get a form: a date picker for the date, a proper phone field for the phone, a dropdown for the choice. They fill it in, and out comes a PNG. That PNG is the record.

The reader decodes the PNG with the password and sees the record laid out field by field, captions and all - not a blob of text to interpret, but the structured thing the designer defined.

Design once, fill many times, read anywhere. If you have ever defined a database table and then generated entry forms and reports from the definition, you already know this shape. To be clear about what does the work: filling and reading both happen in piculum software - the format is nothing without its encoder and decoder. What the design buys you is that the software is a tool, not a service: encoding and decoding run locally, there is no server holding your records, no account to create, and nothing the file phones home to. The record format, the entry form, the transport, and the storage are all the same ordinary image - carried between two ends that run the same tool.

What That Looks Like in Practice

An emergency-info card. Design it once: name, date of birth, allergies (choice list), medications, emergency contact (phone). Fill one per family member. Each card is a photo on a phone that decodes, with the family password, into labeled fields a stranger could act on.

Business paperwork. A registration form, a warranty claim, an inspection record. The business designs the piculum; customers or field staff fill the form; the returned image decodes to a structured record every time, because the structure was designed in, not hoped for.

A software license badge. The vendor designs the badge once: licensee name, product, edition (choice list), seat count, expiry date. Each sale fills the form and issues the badge - a small image the customer keeps and presents when support or activation asks for it. The image itself does nothing; it is the sealed record the vendor's own check reads back. When the vendor decodes a presented badge, they either recover exactly the license they issued or the seal refuses to open - a badge that was edited, forged without the vendor's password, or built against a different template fails at that check rather than decoding to a doctored license. The customer carries the record; the vendor's decode is the verification.

A publisher with tiers. Regions carry their own passwords, so one designed image serves several audiences: the free password opens the hint, the subscriber password opens the solution. The people who can open one region learn nothing about the others.

A note in a photo. The undesigned case still works: encode a private message or a file into any picture and send it as a picture. Useful - just no longer the headline.

For developers, the template is a contract. The field definitions travel with the piculum itself, so a program using the piculum library can read a template, discover its fields and capacities, fill them, and emit the record - or take a record and consume it. It is a form spec, a data envelope, and a distribution format in one file; the library is the only dependency, and no server is involved in reading.

Why It Holds Up

It is just a PNG - with one honest asterisk. As a picture, it needs nothing: every image viewer displays it, everything that stores images stores it, and it travels every channel a photo travels. As a container, it needs the piculum software on both ends - encoding and decoding are the tool's job, not the image's. The asterisk is a small one: the tool runs locally and free, with no account and no server, but it is honest to say the picture carries the record and the software does the work.

The protection is real. Content is sealed with modern authenticated encryption. A wrong password does not produce garbled text to puzzle over - the seal refuses to open. If anyone alters the carrying pixels, the seal breaks visibly instead of decoding to something plausible and wrong. You get the right content or a clear failure, never a quiet lie.

For readers who want the specifics: each region is sealed independently with AES-256-GCM, using a key stretched from your password by PBKDF2-SHA256 at 100,000 iterations with a fresh random salt every time - all of it the browser's built-in, audited WebCrypto implementation, not custom cipher code.

Access is layered by design. Per-region passwords are how piculums are built, not a bolt-on. One file, several audiences.

Capacity is honest. The designer sees, region by region, exactly how many bytes fit - while designing, before anything is filled. No surprises at the end.

The data can have a shape. Regions are painted, not boxed - a field's pixels can be a heart, a scatter of stars, or a precise-capacity blob dropped exactly where the designer clicks. The dictionary is also the art.

The One Rule of Care

A piculum's content lives in exact pixel values, so it survives anything that preserves the file: copying, attaching, storing, downloading. It does not survive being re-rendered - screenshots, photo "enhancement," and messengers that recompress images all repaint the pixels and destroy the carried content (the visible picture stays fine). Send the file, not a picture of the file. And the password is the whole key: there is no recovery back door, so losing it means losing the contents.

In Short

A piculum lets one person define a record - its fields, its types, its capacities, its look - and lets anyone else fill and read that record as an ordinary picture, using the same tool on both ends. It is a data dictionary you can hand to your family or your customers, with real encryption on every region and nothing between the designer and the reader but the file and the software. Design once; the tool and the picture do the rest together.