How to use the DEG 2021 blockchain public key correctly?

Question

blockchain

I saw in the press such a passage "at 21:00 the public key to the blockchain was published and everyone could start their own decryption procedure." In the traditional use of the OPEN/CLOSED pair. Keys. Conversely, the ssh/https or other encrypted protocol server gives the client its public key so that the client can encrypt the traffic, which the client can decrypt with its private key and the server on its side can decrypt with its private key. Isn't there a contradiction here with how the key pairs were used in the DEG 2021 blockchain?

Answer 1

Here, rather, the authors of the passage do not fully understand the situation.
In fact, the votes of users in the DEG data are decrypted using a private key that was made publicly available after the end of the voting.
There is one more thing to keep in mind when voting. - there is a finite number of different votes, and if you use the usual encryption scheme with public / private keys, then it will be possible to simply analyze the current results by statistical analysis during the voting process, which is prohibited by law. Therefore, the DEG uses additional tricks using the user's public key and a random nonce additive.
The decryption procedure has already been posted by many in the public domain, you can look at its implementation here, for example, -https://github.com/heni/moscow2021-evoting/blob/ma...