British Telecommunications PLC (BT), which is the largest telecom and internet provider in the UK, had filed a patent application for a proposed cybersecurity measure to protect blockchain. On October 31st, the US Patent and Trademark office has awarded this patent to BT.
Talk about protecting blockchain from cyberattack can be surprising! Blockchain has a reputation of being very hard to corrupt, due to the fact that it is a distributed database with each node considered as a ledger, and the entire database maintained by all nodes. Changing or deleting existing blocks is not possible, hence, to update a blockchain, a new block has to be created. To create a new block, each “Miner”, i.e. the combination of powerful software, specially designed hardware and their user, has to provide proof of work (POW) for the last recorded block in the blockchain, an operation which is essentially a massive number-crunching done at high speed. This is in an environment where many other miners are also doing the same, which makes it more difficult for any miner to provide POW. This makes updating blockchain very hard, only when proof of very significant number-crunching work done is provided, a miner gets to create a new block. Hacking blockchain is, hence, a very hard thing to do.
It still can be done, though, and that’s what BTs patent application is about. When updating a blockchain, i.e. creating a block, the miners essentially first create a “hash”. A hash is a seemingly random sequence of letters and numbers, which encapsulates the information in the block. The hash is stored along with the block, at the end of the blockchain. It is not the just the transaction data for the new block that is used, to create the hash. The hash for the last block in the blockchain is also needed. This is what makes the processing of mining a very large and resource-intensive number-crunching operation. The “hash rate” is the speed with which the computer does this massive number-crunching. The miner has more chances of updating the blockchain if the hash rate is high. If a cyber attacker procures, or appears to procure, at least 51% (or the majority) of the total mining resources working with a blockchain, and has a high hash rate, then the attacker has a high chance to overwhelm the other nodes, and creating the next block in the blockchain, using which he can then execute his malicious intent.
BT has proposed a technical remedy to this possibility in their patent application. Their proposed computer system has a processor device and a data store. The processor device creates a transaction profile. Transactions can be created according to this profile and submitted into blockchain. The processor then submits a transaction into blockchain, and in turn, creates a profiler data structure. The processor monitors the blockchain, identifies the profile transactions, and compares profile transactions with the transaction creation profile. A deviation from the transaction creation profile is a malicious attack on the blockchain. As soon as a malicious attack is detected, the system stops the blockchain, preventing even the majority or “51%” attack described above, from hacking the blockchain.