| | MARCH 2025ENTERPRISE SECURITY8IN MY OPINIONIN MY OPINIONIN MY OPINIONIN MY OPINIONUSING PERMISSIONED BLOCKCHAINSINTRODUCTIONThe application of blockchain in the media world is usually focusing on two domains: management of digital rights and non-fungible tokens (NFT). Nevertheless, blockchains can have other practical applications in the media chain. This paper presents two such scenarios. They illustrate the potential benefits of using a permissioned blockchain rather than a traditional distributed database.BLOCKCHAINSMy proposed definition of blockchain is "a blockchain is a secure distributed ledger."Thus, a blockchain stores the complete chronological records of transactions. Transactions are combined in a data structure called a block. Each block is cryptographically bound to its predecessor, creating a chain of blocks.A blockchain is a distributed ledger by construction. No central server holds the blockchain. Every participating node has a complete duplicate copy of the ledger. A peer-to-peer network connects the nodes. Therefore, the blockchain offers high availability and resilience. There is not one point of failure in the system.A blockchain is secure. Each issuer signs its proposed transaction. Each node validates every transaction according to validation rules defined by the blockchain's governance. Once all the transactions of the block are validated, the nodes engage in a consensus protocol to decide whether to append the block to the blockchain. Once all nodes reach consensus, they add the new block to their copy of the blockchain. Consensus is the most complex element of the blockchain. Many consensus protocols are available. The two most famous onesare the Proof of Work (PoW) and Proof of Stake (PoS)Transactions 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 stoneACTUAL 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 By Eric DIEHL, VP Media and Content Security, Sony Pictures Entertainment
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