Blockchain is a tamper-proof, shared digital ledger that records the history of transactions between the peers in a peer-to-peer network. This article describes how blockchain technology can be used to protect data and the network from cyber-attacks.
Cyber security is a set of technologies, processes and controls designed to protect systems, devices, data, networks and programs from cyber-attacks. It secures data from threats such as theft or misuse, and also safeguards the system from viruses.
In today’s world, cyber-attacks are major threats faced by each user. Most of us are responsive to the advertisements on various websites on the Internet, and if asked questions or any personal details, respond without even thinking of the consequences. Sharing one’s personal information is very risky, as one may lose whatever one has. In 2016, the search engine Yahoo! faced a major attack and around one billion accounts were compromised. The attackers were able to get the user names, passwords, phone numbers, and security questions and answers of e-mail users. On September 7, 2017, Equifax, one of the largest consumer credit recording agencies in the world, faced a massive cyber security threat. It is believed that someone gave unauthorised access to the data with this agency, from mid-May to July 2017. Around 145.5 million people felt threatened by the news as they had shared personal information like names, social security numbers, birthdays, addresses and driving license numbers with Equifax.
Many people use weak or default passwords for their personal accounts on some Internet sites, which is very risky as these can be cracked, and their personal details can be compromised. This may be even more risky if people use default passwords for all their sites, just for convenience. If the attackers crack that password, then it can be used for all other sites, and all their personal details, including their credit card and bank details may be harvested. In this digital era, cyber-attacks are a matter of real concern. Cyber criminals are greatly increasing in number and are attempting to steal financial data, personal identifiable information (PII) as well as identities of the common Internet user.
Businesses, the government, and the private as well as public sectors are continuously fighting against such frauds, malicious bugs and so on. Even as the hackers are increasing their expertise, the ways to cope with their attacks are also improving very fast. One of these ways is the blockchain.
Blockchain: A brief background
Each block in a blockchain contains transaction data, a hash function and hash of the previous block. Blockchain is managed by a peer-to-peer (P2P) network. On the network, no central authority exists and all blocks are distributed among all the users in the network. Everyone in the network is responsible for verifying the data that is shared, and ensuring that no existing blocks are being altered and no false data is being added. Blockchain technology enables direct transaction between two individuals, without the involvement of a third party and hence provides transparency. When a transaction happens, the transaction information is shared amongst everyone in the blockchain network. These transactions are individually time stamped. When these transactions are put together in a block, they are time stamped again as a whole block. Blockchain can be used to prevent cyber-attacks in three ways – by being a trusted system, by being immutable and by network consensus.
A blockchain based system runs on the concept of human trust. A blockchain network is built in such a way that it presumes any individual node could attack it at any time. The consensus protocol, like proof of work, ensures that even if this happens, the network completes its work as intended, regardless of human cheating or intervention. The blockchain allows one to secure stored data using various cryptographic properties such as digital signatures and hashing. As soon as the data enters a block in the blockchain, it cannot be tampered with and this property is called immutability. If anyone tries to tamper with the blockchain database, then the network consensus will recognise the fact and shut down the attempt.
Blockchains are made up of nodes; these can be within one institution like a hospital, or can be all over the world on the computer of any citizen who wants to participate in the blockchain. For any decision to be made, the majority of the nodes need to come to a consensus. The blockchain has a democratic system instead of a central authoritarian figure. So if any one node is compromised due to malicious action, the rest of the nodes recognise the problem and do not execute the unacceptable activity. Though blockchain has a pretty incredible security feature, it is not used by everyone to store data.
Common use cases of blockchain in cyber security
Mitigating DDoS attacks: A distributed denial-of-service attack is a cyber-attack; it involves multiple compromised computer systems that aim at a target and attack it, causing denial of service for users of the targeted resources. This causes the system to slow down and crash, hence denying services to legitimate users. There are some forms of DDoS software that are causing huge problems. One among them is Hide and Seek malware, which has the ability to act even after the system reboots and hence can cause the system to crash over and over again. Currently, the difficulty in handling DDoS attacks is due to the existing DNS (Domain Name System). A solution to this is the implementation of blockchain technology. It will decentralise the DNS, distributing the data to a greater number of nodes and making it impossible for the hackers to hack.
More secure DNS: For hackers, DNS is an easy target. Hence DNS service providers like Twitter, PayPal, etc, can be brought down. Adding the blockchain to the DNS will enhance the security, because that one single target which can be compromised is removed.
Advanced confidentiality and data integrity: Initially, blockchain had no particular access controls. But as it evolved, more confidentiality and access controls were added, ensuring that data as a whole or in part was not accessible to any wrong person or organisation. Private keys are generally used for signing documents and other purposes. Since these keys can be tampered with, they need to be protected. Blockchain replaces such secret keys with transparency.
Improved PKI: PKI or Public Key Infrastructure is one of the most popular forms of public key cryptography which keeps the messaging apps, websites, emails and other forms of communications secure. The main issue with this cryptography is that most PKI implementations depend on trusted third party Certificate Authorities (CA). But these certificate authorities can easily be compromised by hackers and spoof user identities. When keys are published on the blockchain, the risk of false key generation is eliminated. Along with that, blockchain enables applications to verify the identity of the person you are communicating with. ‘Certain’ is the first implementation of blockchain based PKI.
The major roles of blockchain in cyber security
Eliminating the human factor from authentication: Human intervention is eliminated from the process of authentication. With the help of blockchain technology, businesses are able to authenticate devices and users without the need for a password. Hence, blockchain avoids being a potential attack vector.
Decentralised storage: Blockchain users’ data can be maintained on their computers in their network. This ensures that the chain won’t collapse. If someone other than the owner of a component of data (say, an attacker) attempts to destroy a block, the entire system checks each and every data block to identify the one that differs from the rest. If this block is identified or located by the system, it is recognised as false and is deleted from the chain.
Traceability: All the transactions that are added to a private or public blockchain are time stamped and signed digitally. This means that companies can trace every transaction back to a particular time period. And they can also locate the corresponding party on the blockchain through their public address.
DDoS: Blockchain transactions can be denied easily if the participating units are delayed from sending transactions. For example, the entire attendant infrastructure and the blockchain organisation can be crippled due to the DDoS attack on a set of entities or an entity. These kinds of attacks can introduce integrity risks to a blockchain.
Blockchain for cyber security
One interesting use case is applying the strong integrity assurance feature of blockchain technology to strengthen the cyber security of many other technologies. For example, to ensure the integrity of software downloads like firmware updates, patches, installers, etc, blockchain can be used in the same way that we make use of MD5 hashes today. Our file download that we compare against the hash might be compromised on a vendor website and altered without our knowledge. With a higher level of confidence, we can make a comparison against what is permanently recorded in the blockchain. The use of blockchain technologies has great security potential, particularly in the world of cyber-physical systems (CPS) such as IoT, industrial controls, vehicles, robotics, etc.
Summarising this, for cyber-physical systems the integrity of data is the key concern while the confidentiality in many cases is almost irrelevant. This is the key difference between cyber security for cyber-physical systems and cyber security for traditional enterprise IT systems. Blockchain technology is just what the doctor ordered to address the key cyber-physical systems’ security concerns.
The key characteristics of a blockchain that establish trust are listed below.
- Identification and authentication: Access is granted via cryptographic keys and access rules.
- Transaction rules: At every node standard rules are applied to every transaction.
- Transaction concatenation: Every transaction is linked to its previous transaction.
- Consensus mechanism: In order to agree upon the transaction integrity, mathematical puzzles are solved for all nodes.
- Distributed ledger: There are standards for listing transactions on every node.
- Permissioned and unpermissioned: Ability to participate in a blockchain can be open or pre-approved.
Is blockchain secure?
Blockchain stores data using sophisticated and innovative software rules that are extremely difficult for attackers to manipulate. The best example is Bitcoin. In Bitcoin’s blockchain, the shared data is the history of every transaction made. Information is stored in multiple copies on a network of computers called nodes. Each time someone submits a transaction to the ledger, the node checks to make sure the transaction is valid or not. A subset of the package validates the transaction into blocks and adds them to the previous chain.
The blockchain offers a higher level of security to every individual user. This is because it removes the need for easily compromised and weak online identities and passwords.
How does a blockchain protect data?
Instead of uploading data to a cloud server or storing it in a single location, a blockchain breaks everything into several small nodes. A blockchain protects data because:
- It is decentralised.
- It offers encryption and validation.
- It can be private or public.
- It is virtually impossible to hack.
- It offers quality assurance.
- It ensures fast, cheap and secure transfer of funds across the globe.
- It is well known for its traceability.
- Through it, transactions become more transparent.
Cyber security is a priority, not an afterthought
It seems like in the digital age, comfort and convenience have overtaken things like privacy and security in very unfortunate ways. The handing over of personal information to companies like Facebook is a personal choice; however, no one wants to see information leaked to third parties without consent. The blockchain is all about security. It has provided us a simple, effective and affordable way of ensuring that our cyber security needs are not only met, but also exceeded. We need to understand that the technologies we use to improve our lives can also be used to harm us. That is the reality of the era we are living in, one where most of our personal data is on the cloud, on our mobile device, or on our computer. Because of that, it is vital to look at online safety and cyber security as priorities and not afterthoughts. The blockchain can assist us in turning that thought into reality, and allow us to build a future where online threats are kept to a minimum.
The author is an open source enthusiast. Her interests are developments in open source programming for Arduino IDE and Python IDLE, and real-time image processing using the OpenCV platform supported by Intel.