user1903: The slots and epochs section of the Cardano Stake Pool Course states that the Ouroboros Praos protocol is proprietary.
Is this correct and, if so, is there a reason why this central part of the implementation needs to be proprietary?

user28: That is not correct!
The ledger specifications are licensed under Apache License 2.0 and the paper is also open to public.

1903: <p>The <a href="https://cardano-foundation.gitbook.io/stake-pool-course/lessons/introduction/about-cardano#slots-and-epochs" rel="noreferrer">slots and epochs</a> section of the Cardano Stake Pool Course states that the Ouroboros <a href="https://iohk.io/en/research/library/papers/ouroboros-praosan-adaptively-securesemi-synchronous-proof-of-stake-protocol/" rel="noreferrer">Praos protocol</a> is proprietary.</p>
<p>Is this correct and, if so, is there a reason why this central part of the implementation needs to be proprietary?</p>
 28: <p>That is not correct!</p>
<p><a href="https://github.com/input-output-hk/cardano-ledger-specs" rel="nofollow noreferrer">The ledger specifications</a> are licensed under Apache License 2.0 and <a href="https://eprint.iacr.org/2017/573.pdf" rel="nofollow noreferrer">the paper</a> is also open to public.</p>
