Random Prize Draw
Last updated
Last updated
This random prize draw example leverages the blockchain to ensure integrity and transparency. By using nChain Event's linked records feature, every process step, from ticket generation to the final prize award, is recorded on the blockchain, ensuring that the entire prize draw is open for verification and audit in near real-time. This prevents tampering or manipulation, ensuring that participants can trust the fairness of the prize draw.
An operator devises a prize draw and advertises it globally. They create a linked record (A above) with details such as: the prize, maximum tickets, draw date, ticket price, terms, and conditions. The location of the linked record acts as a unique reference for the draw and can be published immediately.
When the operator creates a ticket, they update the linked records with a new entry (B above). This entry has a unique identifier that serves as the ticket, which is then given to the holder.
The operator creates the number of tickets specified initially using linked records (C, D, E above) and distributes them to holders. For security, each ticket can include a unique code related to the ticket holder, and be encoded. This takes place in near real-time.
When the prize draw occurs, a unique random number is generated by writing a specific record to the linked records (X above). This ensures transparency and fairness, as the operator does not know all of the inputs used to generate the random number, and they cannot attempt generating multiple random numbers.
The winning ticket is identified by the random number and is added to the linked records (Y above) by the operator.
After the winner claims their prize, the operator closes the prize draw and finalises the linked records (Z above).
Note: the whole state of the prize draw is always on the blockchain in near real-time. The prize draw description, the tickets and the winner provenance may be verified by anyone at any time using readily available blockchain browsers.
The records are irrefutably linked together on the blockchain.
Records and timestamps are recorded.
Transparency: Records are publicly accessible globally from the blockchain.
A verifiable and irrefutable proof of the records exists on the blockchain (non-repudiation & tamper-proof).
Uses the blockchain as a global random number generator.
Unique identifiers and random numbers
Example of this random prize draw on the blockchain
Here is an example of this random prize draw on the blockchain.
Follow the links in the table to see the actual records on the blockchain.
Note: you can navigate through all the records in WhatsOnChain by clicking the first input for earlier records, or the last output for later records.
1
File Contents
Global Prize Draw on the blockchain for transparency. 4 tickets, followed by Random Selector and winner.
Encoding and Fingerprint
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Location
(TXID, output #1)
2
File Contents
Ticket1
Encoding and Fingerprint
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Location
(TXID, output #1)
3.1
File Contents
Ticket2
Flower: Pansy
Encoding and Fingerprint
SHA256(23:59:59.123)|Base64
BnU8F5mhlQb4fHQe8jEFugx1K40y7SG/AOhrugFk6+s=
Location
(TXID, output #1)
3.2
File Contents
Ticket3
City: Florence
Encoding and Fingerprint
SHA256(23:59:59.123)|Base64
Eav3xiiP56d/vRnWopYCqXqBKoXZEMkwG8A59BVzwHw=
Location
(TXID, output #1)
3.3
File Contents
Ticket4
Pet: Timmy
Encoding and Fingerprint
SHA256(23:59:59.123)|Base64
PEFDAd5f4vpmgRySKY492zv+3NXYN4FO+2VSkKNbKX8=
Location
(TXID, output #1)
4
File Contents
Random Selector
Encoding and Fingerprint
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Location
(TXID, output #1)
5
File Contents
Winner is picked from 2 LSB of random selector location. 00=>Ticket1, 01=>Ticket2, 10=>Ticket3, 11=>Ticket4
Random location is: 2a0b8764cf5df2899d8c4d7e0670efc028afed1ed2f98aebbc8ad150d2df6065
Last 2 bits are: 01
Winner is: Ticket2
Encoding and Fingerprint
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Location
(TXID, output #1)
6
File Contents
-
Encoding and Fingerprint
-
Location
(TXID, output #1)
See for details about generating unique identifiers and random numbers.
