The blockchain encryption technology provides the trust that people need in the virtual currency Bitcoin. But does using blockchain make sense for e-voting too? POLYAS relies on a similar but more flexible solution: the bulletin board. This post explains the reasons behind this decision.
In recent years, the value of the Bitcoin crypto currency has repeatedly made headlines. The record to date was almost US$ 70,000. The fact that people are willing to invest in a purely virtual currency is down to the blockchain encryption technology. This guarantees that each crypto coin exists only once and that ownership is undisputed thanks to a digital ledger. So if people trust blockchain technology with their money, why not e-voting?
POLYAS relies on secure bulletin boards
In fact POLYAS, as a provider of online voting, uses a technology that is closely related to the blockchain: the bulletin board. Both technologies are based on the same mechanism and aim to provide forgery-proof documentation.
After all, the cryptography methods are basically digital ledgers with individual sections that are interlinked by mathematical processes like links in a chain. The thing is: The entries in this database cannot be changed subsequently.
Important differences with hosting
The main difference between the blockchain and bulletin boards used by POLYAS is that the blockchain is hosted decentrally (i.e. on a large number of servers), while the—similarly public—bulletin boards are stored centrally.
This makes them more energy-efficient, flexible to use, faster or, in one word: scalable. In the IT world, scalability means the ability of a system to grow, i.e. to provide space for an increasing amount of data.
No scalability of the blockchain in e-voting
If you were to run e-voting via the blockchain, this would incur long waiting times for the result of a vote or election—a situation that is unacceptable, as in particular live voting can require the result to be available within seconds.
As mentioned above, the blockchain and bulletin boards are technically very similar: With both of these data logging systems, any new addition results in the calculation of a new hash value. When new information is added, this is combined with the previous hash value to form a new hash value. This process can be continued. Both the information and the hash value are signed. This ensures that new information is saved, but cannot be changed or deleted unnoticed.
Verification of elections with bulletin boards
The bulletin board uses this method to document which ballot papers (encrypted, of course) have been entered into the digital ballot box. Once a bulletin board is sealed, no new information can be added to it. Authorized persons can then review the entries to the bulletin board. The contents of the bulletin boards are the basis for the procedure that POLYAS uses to verify voting secrecy.
So that’s the way it is until further notice: Despite less decentralization, bulletin boards offer forgery-proof documentation and are clearly superior to blockchain in terms of scalability for e-voting.