Blockchain technology has significantly changed the way in which traditional networks operate. It is based on the concepts of cryptography, decentralisation and consensus, which have revolutionised record-keeping. Aside from improving the speed and efficiency of transactions, it provides many security benefits through cryptographic validation and improving the transparency of records. The misconception, however, is that it is fully secure by default. Judging from historical successful cyber attacks on existing blockchains, the answer is yes. This begs the question: given the inherent security principles in the design and operation of the blockchain, what vulnerabilities could exist and how have they been exploited? Blockchains are classified into various types, distinguished by whether they are open to anyone or restricted to known participants, and whether they are permissioned or not. Permissioned and restricted – or ‘closed blockchains’ – are believed to offer higher levels of security. They provide greater control over who can participate and what activities they can perform. The decision on the type of blockchain to implement is usually a question of the relative importance of security compared with performance of the blockchain.
Full story : How cyber secure is blockchain technology?