One of the UK's largest telecoms is seeking a patent for a security system aimed at preventing malicious attacks on blockchains.

British Telecommunications (BT) PLC submitted a patent application last July for “Mitigating Blockchain Attacks” to the US Patent and Trademark Office (USPTO). The application, released on 2nd February, details both a system and methods for monitoring transactions on a particular blockchain in a bid to “detect malicious attacks”, the application’s authors write.

The filing is notable given its source, as BT is the largest Internet service provider in the UK, according to recent marketshare data. The patent also represents BT’s first known involvement with the tech.

While the application doesn’t detail which blockchain is addressed by the patent – whether bitcoin, ethereum or some kind of private ledger – it does directly reference mining, or the energy intensive process by which new transactions are added to the chain.

The proposed system, according to BT, could be used to create a “a transaction creation profile”, suggesting that it would be applied to a permissioned network in which only certain participants are allowed to submit transactions.

As the application notes:

Other threats identified in the application include 51% attacks, through which an entity controlling a majority of hashing power has the theoretical power to start reordering transactions.

"Other attacks also pose a threat to the blockchain and its users, including: the Sybil attack in which an entity attempts to fill a miner network with clients controlled centrally or pseudonymous miners; and various denial of service attacks such as sending excessive data to a miner to overwhelm the miner such that it cannot process normal blockchaintransactions," the application goes on to state.

BT isn't the first telecom to attempt to patent a blockchain-related technology. Last year, AT&T filed an application with the USPTO for a kind of home subscriber server that utilizes a blockchain.

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