Win an NVIDIA GeForce RTX 4090!

How many jelly beans in the jar? Record your tamper-proof vote in RKVST for a chance to win



Congratulations to Kiley.Smitham aka Max Kettenhofen, winner of our Jelly Bean Challenge, who went home with an NVIDIA GeForce RTX4090!

To ensure we couldn’t cheat, we counted the beans ahead of the vote opening and attested the number on Instaproof with this document. You can verify this for yourself by downloading it and dragging and dropping it on to Instaproof.

If you’d like to find out more about how we used RKVST to run this challenge using public attestations and transparent claims, check out this blog by Jon Geater.



Vote with RKVST and you’re making a public attestation. Your vote is both transparent and verifiable and is stored on an immutable ledger so it can’t be hacked or spoofed. Your personal information is also never disclosed. Use our API to register additional votes and increase your chances of winning.

And it’s that simple to add verifiable provenance and trust to the data in any app – image files, invoices, software, cloud storage. RKVST offers a digital trust model everyone can rely on.

Group 118
Group 41

Basic level

Vote directly using the RKVST web UI.

Group 41 1

Pro level

Use our API to vote multiple times.

Group 41 2

Elite level

Verify the votes and tell us if you’re the winner!


Participating can be as simple or as deep as you like


Vote directly using our web UI. Just scan the QR code or click the VOTE NOW link and cast your transparent and verifiable vote. It’s that simple!

You’ll need an RKVST account to vote.

RKVST jellybean QR static


Want to increase your chances of winning? To up your game, vote multiple times using the RKVST API. The easiest way to do this is to use our Postman collection, but you can also copy the JSON and REST fragments from there to use in whatever client you like, even our built-in OpenAPI console.

To keep it fair we’ll only recognize your first 10 votes, and this is an evidence platform… we can check!

NOTE: Using the API requires an API credential and an access policy to allow that API credential to vote on your behalf.

There are a few ways to do that – including the UI – but you guys are Devs so let’s do it the fun way 😉

Once you’ve created your App Registration head on over to the Developer Console and scroll down to ‘AccessPolicies’ and ‘POST /archivist/iam/v1/access_policies’. Click ‘Try it out’ then paste this JSON block into the body box (substituting the CLIENT_ID with your application registration CLIENT_ID) and click ‘Execute’:

    "display_name": "Jelly Bean Voting Policy",
    "description": "Allows your application credential to vote in the WAD Jelly Bean Challenge",
    "filters": [
            "or": [
    "access_permissions": [
            "subjects": [],
            "behaviours": [
            "include_attributes": [],
            "user_attributes": [
                    "or": [
            "asset_attributes_read": [
            "asset_attributes_write": [
            "event_arc_display_type_read": [
            "event_arc_display_type_write": [

JSON + REST interface

Don’t be scared to proceed! If you want a little more encouragement to click the Postman button and play with the API here’s an example of how simple it is to register your vote on the platform.

First grab an auth token (hint: this command requires jq and tr: if you don’t have them then you can grab the token out of the full response payload):

RESPONSE=$(curl \
  --data-urlencode "grant_type=client_credentials" \
  --data-urlencode "client_id=$CLIENTID" \
  --data-urlencode "client_secret=$SECRET")
TOKEN=$(echo -n $RESPONSE | jq .access_token | tr -d '"')
echo $TOKEN

Then cast your vote:

curl -v -X POST \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-type: application/json" \
  --data-raw '{"behaviour":"RecordEvidence","operation":"Record","asset_attributes":{},"event_attributes":{"arc_description":"Cast a vote","arc_display_type":"Vote","vote_value":"YOUR GUESS NUMBER"}}' \$YOUR_VOTE_ASSET_ID/events

TLDR check out this video walkthrough and cheat sheet


Think you’ve got what it takes to verify the votes and prove who won? Why not tell us who the winner is! We’ll post the number of jelly beans in the jar to this website at 16:05 CET on 28 July 2023. You have just less than one hour to verify the results before we announce the winner at 17:00. The challenge is on!

It can’t be too easy so we’ll leave the details to you, but they’re all easily found in our developer documentation. Depending on how deep you want to dig:

  • You can prove that the answer we give matches the one we attested to before the event
  • You can find all the votes that entered the correct number
  • You can verify which was entered first
  • You can find how many votes a participant cast (did they exceed their 10?)
  • You can find the blockchain entry for the winning vote and mathematically prove that it won!


RKVST uses a combination of blockchain, SCITT, and other techniques to demonstrate that we can’t tamper with the evidence in the platform. It is fully tamper-evident even against us!

We will post a secret-but-verifiable record of the answer to the chain before the event and will not be able to change it later!

No. Your real name and email address is never disclosed in the public-facing view of your votes. Just like in real digital supply chain operations we need to maintain a balance of strong provenance and integrity guarantees with respect for privacy.

Of course this is just a toy to get you into RKVST. In the real world it can be used for much more than voting: we have use cases in media provenance, spotting fake data in cloud systems, streamlining supply chain operations… any time you need to know your data is authentic we can help.

Group 41 2


We’re running this challenge at the WeAreDevelopers World Congress, 27-28 July 2023 in Berlin. You can find the jelly bean jar on the RKVST booth #AS34.

Not at the event, but still want to participate?

Here’s a photo of the jar.

WAD23 Jelly bean jar

The small print

  1. The RKVST Jelly Bean Challenge is open to anyone.
  2. Participants must enter their vote for the correct number of jelly beans using RKVST, it’s free to sign up.
  3. Participants may vote up to 10 times.
  4. There will be one first prize winner. The winner will be determined by the vote closest to the correct number of jelly beans in the jar. If there is more than one correct vote, the vote that was registered first will be the winner. Entrants need not be present to win.
  5. First prize is an NVIDIA® GeForce RTX™ 4090 GPU Founders Edition with 24 GB of G6X memory. There is no cash alternative.
  6. Votes must be registered before 16:00 CET on Friday 28 July 2023.
  7. The correct number of jelly beans in the jar will be posted to this website at 16:05 CET, Friday 28 July 2023.
  8. The winner will be announced at 17:00 CET, Friday 28 July 2023 on the RKVST booth #AS34 at the WeAreDevelopers World Congress, Berlin, Germany.