One of blockchain’s main selling points is that all of its transactions are public. Even in private blockchains, transactions can be public to all of the participants in that network.  

But that can also be a major drawback, since many kinds of transactions need to remain private because of the financial terms, the competitive strategy, the personal info or other reasons.  

An Estonia-based startup is now out with a possible solution. Lightstreams has launched a blockchain network with a new Permissioned Block protocol that employs smart contracts to grant, block or revoke access to content for specific users.

“The blockchain is broken at the moment in terms of privacy,” said Lightstreams CEO/founder Michael Smolenski in a statement. “It’s simply too public.”  

His company’s solution is a modification of the popular Ethereum blockchain protocol. With Permissioned Blocks, users who have been granted access by a smart contract’s author can share content or transactional info with other users with similar access. Or the smart contract’s owner can determine which users get access to attached content, or under what conditions they will get access, such as after making a payment.