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Home Academy Module 23 — The SHA-256 sealed report
Module 23 · Fortress · 8 min

Freeze a moment, and prove it hasn't moved.

Sometimes you want to keep a photograph of a month — for your records, for yourself. Ozorys can seal that report with a SHA-256 fingerprint: proof it hasn't been retouched by a single cent.

A snapshot that holds

A budget lives, moves, gets corrected. But sometimes you want to keep a frozen photograph of it: June exactly as it stood, once closed. Ozorys can produce that report — a readable snapshot, to keep in your own records.

The point isn't to complicate things: it's to give you a stable reference point, a version you know will never change again.

SHA-256, the tamper-proof fingerprint

To that report Ozorys attaches a fingerprint: a string of 64 characters computed by SHA-256. Its magic fits in one sentence — change a single cent in the report, and the entire fingerprint becomes unrecognisable. It is therefore impossible to retouch the document without the fingerprint giving it away.

The demonstration below makes it visible: write a summary, change a figure, and watch the fingerprint swing completely.

The SHA-256 fingerprint — demonstration

Write a summary of a month. Below it, its 64-character fingerprint. Change one cent: the entire fingerprint changes. That's what makes a forgery impossible to hide.

Teaching illustration. The real seal uses SHA-256; any change, even of one cent, produces a completely different fingerprint.

What it's really for

This seal serves you first of all: comparing two versions, proving an archive hasn't moved, recovering an exact state. It can also accompany a snapshot you choose to show, attesting that it hasn't been retouched since it was created.

A point of honesty, on the other hand: this report is not an official document, nor an accounting record, nor advice. It's your personal archive, generated by you — its value is whatever you and the people you show it to grant it.

What it is, and what it isn't

A reliable snapshot for your own purposes: yes. Official proof you could rely on legally: no. Ozorys remains a personal management tool, never a certified trusted third party.

The report, without betraying the vault

Even sealed, this report honours Zero-Knowledge: it's computed and signed on your device, from your data alone. Nothing passes through our servers, nothing leaks. You produce the proof at home, for yourself.

That's the consistency of the whole Fortress: right down to the attestation, the principle holds — your data isn't ours, not even for the length of a report.

The proof stays with you

Sealing a report doesn't expose it: the computation happens locally. You gain proof of integrity without surrendering a byte of privacy.

Let's check it stuck

Six questions, marked instantly. Your answers never leave this page.

1. What is the sealed report for?

A stable reference point, a version you know will never change again.

2. What does SHA-256 produce on this report?

The fingerprint is the seal: it condenses the document into a fixed string of characters.

3. If you change a single cent in the report…

That's what makes a forgery impossible to hide: the fingerprint gives away any retouching.

4. Is this sealed report an official document?

Ozorys remains a personal management tool, never a certified trusted third party.

5. Where is the seal computed?

Even the attestation honours Zero-Knowledge: nothing leaks.

6. Does sealing a report expose your data?

You gain proof of integrity without surrendering a byte of privacy.

Today's challenge

Open the demonstration, type “June budget — €1,842.50”, note the fingerprint, then change the amount to “€1,842.51”. Watch all 64 characters swing completely: you hold the intuition that makes any forgery visible.

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