Be careful, Blockchain is not a wild card.

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Every tool has been designed to accomplish a certain task or purpose. is not different from other tools and it has a specific functionality. As you will see below, it provides a set of properties that are very useful to protect information.

Blockchain is not something new in cryptography.

Blockchain is, in essence, a signed hash chain. This is a combination of data, hashes and signatures composing an interwoven chain. Although Blockchain is a hot topic nowadays, its underlying has been used for years to protect information. The generation of immutable audit logs is a good example of this.

The idea behind Blockchain consists in signing the content of every data record together with the result of a hash function of the previous stored record. In this way, signatures become successively connected by themselves allowing anyone to check their correctness.

From a security point of view, Blockchain provides data integrity, data authenticity, non-repudiation, record immutability, verifiability, and fault-tolerance.

Each of these digital signatures provides data integritydata authenticity and non-repudiation to its corresponding record: (i) When the data of a record is signed, it cannot be modified once generated without detection (data integrity); (ii) only the issuer of a signature is able to prove that the signature belongs to her (data authenticity); and (iii) the issuer of a signature cannot deny her authorship (non-repudiation).

Meanwhile, the hash included in each signature links such record with the previous one. This hash together with the digital signature offer record immutability. In other words, records cannot be added, modified or deleted without detection. This is because any fraudulent change can be detected by verifying from the last to the first linked signature of the chain. Anyone who possesses the public key of the signatures is able to check it (verifiability). In fact, this is the reason why Blockchain is not anonymous.

In addition, Blockchain provides data redundancy, which consists in storing a copy of every record in several peers. Therefore, if a server fails, the other servers still have the whole data (fault-tolerance).

All these properties make Blockchain a good tool to store information in a secure way. But, as each tool, Blockchain has limited properties and functionalities. It cannot solve as many problems as we would like.

Analyse what security requirements have to be met by your system, and decide then what cryptographic techniques to use.

For this reason, it is important to figure out what functional as well as security requirements have to be accomplished by your system and whether Blockchain is your suitable tool.

Is Blockchain what you need?

Keep in mind that there is not a magic tool able to deal with all your system requirements. On the contrary, an improper use of a security tool could lead to your system a serious security fault.


  is Information Security & Privacy Architect at Dinube