Blockchain for Digital Identity

Blockchain for Digital Identity

The potential use cases of blockchain technology are numerous, but one of the most promising ones is digital identity management and verification. Personal data breaches affected billions of people worldwide in 2018, highlighting the urgent need for secure storage, transfer, and verification of sensitive information. Centralized databases face challenges, and blockchain systems may provide valuable solutions.


Digital identity systems can benefit from blockchain technology by ensuring the authenticity of information through network nodes. When a file is recorded on a blockchain, the network's nodes validate its accuracy by supporting the validity of all recorded data through multiple users' claims. Governmental institutions or authorized agencies can control the network nodes responsible for verifying and validating digital records. Each node can vote on data authenticity, enabling the files to function as official documents with enhanced security features.

The Role of Cryptography

Cryptography plays a crucial role in blockchain-based identity systems. These systems don't require explicit sharing of sensitive information but can authenticate digital data using cryptographic techniques like hashing functions, digital signatures, and zero-knowledge proofs.

Using hashing algorithms, any document can be transformed into a digital fingerprint called a hash, representing all the information used to create it. Trusted entities can provide digital signatures to give the official document validity. For example, a citizen could provide a document to an authorized agency, generating a unique hash that can be digitally signed, thereby making it an official record.

Zero-knowledge proofs enable credentials or identities to be authenticated without revealing any specific information about them. Even if data is encrypted, its authenticity can be verified. This means that with ZK proofs, you can prove you are old enough to drive or enter a club without revealing your exact birth date. As a result, blockchain-based identity systems offer secure and reliable ways to authenticate sensitive information without compromising privacy.

Self-Sovereign Identity

Self-sovereign identity is a model where users have complete control over their data, which could be stored in personal wallets similar to crypto wallets. Each user can decide when and how their information is shared. A person could store credit card credentials in a personal wallet and use their private key to sign a transaction that sends that information out, proving that they are the true owner of the credit card.

Although blockchain technology is primarily used for storing and exchanging cryptocurrencies, it can also be used to validate personal documents and signatures. For example, a person can have a government agency sign off on their status as an accredited investor and transfer confirmation of that fact to a brokerage via a ZK proof protocol. As a result, the brokerage can be sure that the investor is properly accredited without detailed knowledge about their net worth or income. Blockchain-based self-sovereign identity solutions offer more control and security to users over their personal data.

Potential Advantages

Digital identity systems could potentially benefit from the implementation of cryptography and blockchain technology, providing various advantages. Firstly, users could have greater control over how and when their personal data is used, resulting in a reduction in the risks associated with storing sensitive information in centralized databases. Secondly, blockchain networks could provide higher levels of privacy through the use of cryptographic systems, such as zero-knowledge proof protocols, allowing users to authenticate their documents without revealing specific details about them.

Furthermore, blockchain-based digital identity systems could be more reliable than traditional ones. For instance, digital signatures could help verify the source of a claim about a user, making it relatively easy to authenticate. Additionally, blockchain technology could make it more challenging for a person to falsify data, providing more excellent protection against fraud.

Potential Limitations

When implementing blockchain for digital identity, some potential limitations should be considered. One of the most significant challenges is the risk of synthetic identity theft, which involves creating a new identity by combining accurate information from various individuals. Such attacks may trick some systems into recognizing the fake ones as legitimate, making them vulnerable to credit card fraud. However, using digital signatures could prevent this by requiring signatures for individual documents and a common signature for all documents registered by the same individual.

Another concern is the possibility of 51 percent attacks, which could reorganize a blockchain and alter its records. While public blockchains are more susceptible to such attacks, private blockchains can minimize this risk by limiting validators to trusted entities. However, this approach could lead to a more centralized model, which may be less democratic. Despite these potential limitations, using cryptography and blockchain for digital identity still holds promise for enhancing user control, privacy, and reliability.


The potential of blockchain technology in revolutionizing digital data verification, storage, and sharing is immense, despite its limitations and challenges. Many companies and startups are already exploring blockchain's possibilities, so this technology is anticipated to be a fundamental element in upcoming services concentrating on digital ID management. While much work is still to be done, the potential benefits of blockchain-based digital identity systems are too great to ignore. 

Digital Identity