As we are aware that blockchain is a decentralized application and it is tough to implement user identity mechansim in decentralized application so we use digital signature to verify the identity of a user. A digital signature comprise of a public key and encrypted message. A digital signature is issued by a trusted certificate authority and we can verify the digital signature from that authority. My question is so how can it make sure in blockchain network that a digitally signed transaction is done by an authentic blockchain user.
This article can be useful for your study and possibly give an answer for your query:
frozeman started a new ERC last month to discuss user identification:
The following describes standard functions for a unique identity for humans, groups, objects and machines. This identity can hold keys to sign actions (transactions, documents, logins, access, etc), and claims, which are attested from third parties (issuers) and self attested, as well as a proxy function to act directly on the blockchain.
And he talked about this during devcon3:
Fabian Vogelsteller (author of ERC20) will be talking about his new work on standard functions for a unique identity for humans and machines. https://www.youtube.com/watch?v=pkwYVagytuA&index=7&list=PLaM7G4Llrb7zOVvbMYqEXSYCFIoRql_vE