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Verified Football Predictions: How Our SHA-256 Seal Proves Nothing Changed After Kick-off

6 min read October 2026

The first question anyone should ask a prediction service is simple: were the picks changed after the matches? Results pages can be edited, losing picks can quietly disappear, odds can be "corrected". Our answer is not a promise. It is a seal you can check yourself, every day, without trusting us.

1. What a seal is

Before the first match of the day we take every list we published and run it through SHA-256, a standard cryptographic function used in banking and software updates. The result is a 64-character fingerprint. The same list always gives the same fingerprint; change a single character — one pick, one odds value, the order of two lines — and the fingerprint is completely different.

Real SHA-256 values: the odds change by 0.01 and the whole fingerprint changes. A sealed list cannot be edited without the seal breaking.

We post that fingerprint on our public channels before kick-off. The next morning, when every result is in, we publish the lists themselves. Anyone can hash them again and see whether the result matches the fingerprint that was posted the day before.

2. What we seal every day

One seal covers everything we published for the day — eight lists, one fingerprint:

List	What it is
Today's Picks	The full daily board, in board order.
Landing Picks	The short list on our homepage, ordered by confidence.
High Odds	Bets in the high odds band.
Low Odds	Bets in the low odds band.
Bankroll order: Today's Picks	The order the Premium Bankroll uses for Today's Picks: bets that pass the odds and value floors, sorted by expected value.
Bankroll order: Landing Picks	The same matches as Landing Picks, sorted by expected value.
Bankroll order: High Odds	The High Odds bets in the Bankroll's order.
Football Bankroll League · AI plan	The plan ExPrysm plays as an opponent in the Football Bankroll League.

The order matters as much as the picks: when you choose the top 10 or the top 30 in the Bankroll, you choose from a ranking that was sealed before the day started.

3. What is not sealed, and why

Late picks are not in the seal. They are set about one hour before kick-off, when confirmed line-ups arrive — after the seal has been posted. The same applies when a line-up check drops a sealed bet: the bet stays in the sealed list, it is marked as dropped and it is not counted as a win or a loss. Every such change is listed separately on the seal page, with its approximate time.

4. The daily timeline

The seal goes public before the first kick-off; the lists open only after all results are in.

The order is what makes it work. The fingerprint becomes public while every match is still in the future, and the content becomes public only when the results are complete — so there is no moment where we could see a result and still change the list.

5. How to verify it yourself

The ExPrysm prediction seal page with the seal, the check button and the sealed lists — The seal page: the fingerprint, the links to the public posts, the "Check in my browser" button and every sealed list with its results.

On the seal page you can press "Check in my browser". Your browser — not our server — downloads the raw file and calculates the fingerprint. If you prefer not to trust our page at all, do it with your own tool:

Download the raw file from the seal page.
Join three fields exactly as written in the file, separated by a | sign: prev_hash | salt | body_canonical.
Hash the text with SHA-256 using any tool (command line, a programming language, an independent website) and compare the result with the fingerprint we posted before kick-off.

python3 -c "import json,hashlib;d=json.load(open('seal_2026-10-23.json'));print(hashlib.sha256((d['prev_hash']+'|'+d['salt']+'|'+d['body_canonical']).encode()).hexdigest())"

Why the public post matters. The button on our page proves nothing on its own — we serve both the page and the file. The independent evidence is the post: its time is set by the platform, and a post cannot be backdated. Compare against that.

6. What the seal proves — and what it does not

It proves that the picks, odds and order you see in the revealed lists are exactly what we locked before the first match.
It proves that no losing pick was removed and no line was added after the results.
It does not prove that the picks are profitable. That is what the results are for: they are shown next to every sealed line, wins and losses alike, and the long-run picture is on the performance page.

7. A chain, not a single day

Each seal also contains the previous day's seal. Rewriting any past day would change its fingerprint and break every seal published after it — all of which are already public. The history can only be extended, never edited.

8. Frequently asked questions

Why don't you show the lists before the matches?

The lists are the product our members pay for. The seal lets us prove that they did not change without publishing them early: the fingerprint is public, the content stays private until the day is over.

What is the salt for?

The salt is a random secret value added before hashing. Without it, someone could try to guess a short list by hashing many candidates. With it, the fingerprint reveals nothing until we publish the salt.

Could you create several seals and publish only the best one?

Only one seal is posted per day, on public channels where the platform sets the time. Each seal also contains the previous one, so a second version of any day would not fit the chain that was already published.

Are the results part of the seal?

No. The seal covers the picks, odds and order before kick-off. Results are added next to it for reading and use the 90-minute score.

Why are late picks not sealed?

Late picks are set about one hour before kick-off, when confirmed line-ups arrive — after the seal is posted. They are listed separately on the seal page with their approximate time.

Not a betting site. ExPrysm publishes analytics and model output across 650+ leagues & tournaments for research purposes. Past results do not guarantee future results, and nothing here is financial advice. Bet only what you can afford to lose. 18+.

— ExPrysm Team