1) Signing Certificates are issued by designated Certifying Authorities after a detailed verification of identity of the Signature Holder. This ensures that impersonation of the Signature Holder (Universities / Colleges) is ruled out.
2) The Signature Holder can use the Signing Certificate to sign documents, and this requires 2 factor authentication. If a Certificate is misplaced or compromized, there is a process to revoke / cancel such a Signing Certificate, thereby rendering it useless.
3) A Signed document can be verified simply by opening it in an Adobe Reader. The Signature panel immediately shows if the document is signed / modified after signing, and the identity of the Signer can be verified via the Signature Panel. There is no need to upload the document anywhere or visit any website. Verification of documents in bulk can also be automated.
4) Signed Documents cannot be tampered without breaking the Signature, and therefore these can be uploaded to repositories. The Govt therefore correctly selected Digital Signature Technology for its repositories such as Digilocker and NAD.
5) Digital Signature implementations come at significantly lower costs since there is no need to maintain distributed ledgers, etc.
1) There is no Govt body that governs or defines how the identity of a block chain participant is to be verified.
2) Every time one needs to verify a document, it has to be uploaded to a specific website. This in turn brings the risks associated with phishing.
3) Block chain is not compatible with various initiatives of the Govt including Digilocker.
4) The costs associated with Distributed Ledgers are always higher.
5) Finally, there is no legal framework in place governing Block-chain documents.
To summarize, Educational institutions in India are better off authenticating their documents with Digital Signatures as opposed to using distributed ledgers / block chains.