The Entry Verification Record (EVR) is a new initiative by the Colorado Lottery that allows players to validate that their Bonus Draw or Contest entry was received. The EVR is a public daily record of all entries submitted to the Colorado Lottery, as well as a public record of each entry included in a given drawing. The EVR manifest ensures that there is a public audit trail, allowing independent verification that past data has not been altered.
To preserve the confidentiality of player data, this information is all encrypted as hashes, unique 64-digit strings of numbers and letters that you can match to our records. The hash calculator on this page will allow you to generate the hash for the entry you wish to verify. Just input your name, email address, and the confirmation number from your entry.
Each morning, the Colorado Lottery will publish a Daily File on this page containing the hashes for each entry received the previous day, including entries for both Bonus Draws and Contests. You may search this daily file for the entry hash generated above to verify that your entry was received on that specific day. Similarly, each time a drawing is conducted, the Colorado Lottery will publish a Drawing File containing the hashes for each entry that was eligible for that drawing. You may search this drawing file for the entry hash generated above to verify that your entry was included in that specific drawing.
For more information on how to utilize the Entry Verification Record for purposes beyond verifying a single entry, please see the instructions below.
Technical Details
Entry Hash
An entry's hash is the sha-256 of the utf-8 encoded concatenation of:
[confirmation number],[the full name on the entry],[email address]
The sha-256 hash is represented in hex in the daily files.
For example: confirmation number 123, full name John Doe, email address foo@test.com, or 123,John Doe,foo@test.com, hashes to:
3b09bc3fa5c9d269d89fc6c3e5cbee79da3ab65dc39038b168e9fbe1e9f9fd48
You may calculate the entry hash by using the calculator on this page or any other SHA-256 hash calculator.
Verifying an Entry
Once you have calculated the entry hash, you can verify that an entry was received by the Colorado Lottery by searching for the entry hash in the daily file for the date the entry was submitted. You may also search for the entry hash within a drawing file to verify that the entry was included in a particular drawing.
Daily Files
Daily files contain two columns: the entry's hash, and the Jackpot or Scratch game name.
Recent daily files can be found on this page. Archived files are published at at URLs in the following format:
https://www.coloradolottery.com/evr/archive/[date, in ISO-8601 format].csv
For example: https://www.coloradolottery.com/evr/archive/2021-11-08.csv
Manifest
A manifest is published with three columns: date, hex-encoded sha-256 of that day's entry file, and hex-encoded sha-256 blockchain hash.
Verifying the Daily File
You can also use the manifest to verify the contents of the daily file. Uploading the entire daily file to a SHA-256 hash calculator should result in the same hash that appears in the second column of the manifest entry for the date of the daily file.
Verifying the Blockchain
The manifest will allow third parties to easily detect modifications to historical daily files. Each entry in the manifest includes a blockchain hash, which is the hash of the previous day's blockchain hash and the daily file hash.
Once you have verified the blockchain up to a certain date, you only need to remember that date's blockchain to be able to detect modification of historical data, as changes to any entry data would alter the blockchain hash in the manifest.
Independent Verification
To learn more about running an independent verifier, see our GitHub.