Media & Entertainment9 DECEMBER - 2022Transactions are immutable. To alter an already recorded transaction, an attacker would have to modify the forged transaction block and adjust all subsequent blocks to maintain the cryptographic link. Furthermore, the attacker would also have to trick the consensus protocol into voting the forged fork as valid. Thus, it is reasonable to assume that the transactions are carved in stone3 Actual useSony Pictures is exploring the use of blockchains in a Business to Business (B2B) context. As the use cases are exclusively in B2B, all the entities interacting with the blockchains will be known.Therefore, a permissioned blockchain was the appropriate choice. Blockchains like Bitcoin, Ethereum, or Solana are permissionless blockchains. Anybody can participate in it, is not necessarily trusted, and is relatively anonymous. A permissioned blockchain knows and trusts all its participants. Thus, its trust model is simpler than a permissionless blockchain. Consequently, the consensus methods are simpler, faster, and less energy-guzzling than PoW or PoS. We selected Hyperledger Fabric 2.2.The first use case is Atheneum: management of theatrical release dates. Usually, movies are not released in every territory on the same day. The choice of releases depends on many parameters. International distributors distribute films in their respective territory. Each distributor is granted the right for a given set of countries. The smart contract of Atheneum enforces that the granted rights are compatible with the distributor’s territory and that the local release date is compliant with the studio’s decision. Atheneum supports multiple studios. A Decentralized Autonomous Organization (DAO) streamlines the enrolment of new studios and distributors into Atheneum.The second use case relates to Digital Cinema. The secure distribution of movies to digital theaters encrypts the content into an encrypted container. Each authorized projector receives the decryption key in a message encrypted for the projector. Each digital projector has a unique public-private RSA key pair. This targeted encryption requires knowing a piece of information, the public key, unique for each projector. If this information is inaccurate, the projector cannot decrypt the movie, resulting in a black screen, otherwise an unauthorized projector could decrypt it, resulting in potential piracy. A Trusted Device List (TDL) maintains this list of public keys and their associated projectors. BCTDL is a blockchain that manages the public key of every theater's projector. Furthermore, the BCTDL smart contract implements a protocol that proves that a projector is really in the claimed theater.All these blockchains use an in-house-developed framework: SPBF (Sony Pictures Blockchain Framework). SPBF simplifies the development of smart contracts and wallets by encapsulating and enriching the features of Hyperledger Fabric. For instance, it provides an RBAC (Role Based Access Control) for the smart contract designer. SPBF enforces that only the non-revoked issuers with the proper role can request some transactions. As the issuer’s signed public key holds the role, the RBAC is robust against forgery.4 Why a blockchain?The logical question at this point is whether to use a distributed database. The answer is: it could. Nevertheless, blockchains introduce many benefits over a distributed database. Following is a non-ordered list of advantages.• The reader may have noticed that the two disclosed projects have a scope wider than one unique studio. They target a wide range of content producers. A blockchain is better suited for sharing operations/responsibility amongst different actors than a database. It is a shared, non-proprietary resource. • Smart contracts are elegant and efficient methods to implement/enforce business logic in a secure, distributed manner. There is no one unique point of failure or attack.• Blockchain inherently implements strong security, such as authentication of the issuer, non-forgeability of transactions, or traceability. Using a permissioned blockchain ensures that only known entities interact with the blockchain and perform only operations they are entitled to.Blockchain also brings its set of issues. The most important one is that it is a relatively new paradigm.The industry is still at the bottom of its learning curve. Finding skilled practitioners is difficult. Some key issues are not addressed. For instance, protecting the entity's private key is entirely the implementer's responsibility. Indeed, this challenge is real for any security system but may be more critical in the scope of blockchains.5 ConclusionsFor most people, blockchains are intimately associated with hyped cryptocurrencies and NFTs. Fortunately, blockchains have practical non-monetary, applications without implying hyped concepts. We presented two such applications. In controlled environments, permissioned blockchains may be valid alternatives to permissionless blockchains. They offer the same resilience and immutability. They are faster, cheaper, and more secure than their permissionless counterparts. They enable competing organizations to collaborate without biding to a competitor’s system. USING PERMISSIONED BLOCKCHAINSUsing a permissioned blockchain ensures that only known entities interact with the blockchain and perform only operations they are entitled to
< Page 8 | Page 10 >