Key exchange with the help of a public ledger
This addresses security vulnerabilities in key exchange for users in distributed systems, offering a novel approach but with incremental improvements in user interaction.
The paper tackles the problem of man-in-the-middle attacks in key exchange protocols like Diffie-Hellman by leveraging the consistency property of public ledgers to detect and prevent such attacks, eliminating the need for prior knowledge or trusted third parties.
Blockchains and other public ledger structures promise a new way to create globally consistent event logs and other records. We make use of this consistency property to detect and prevent man-in-the-middle attacks in a key exchange such as Diffie-Hellman or ECDH. Essentially, the MitM attack creates an inconsistency in the world views of the two honest parties, and they can detect it with the help of the ledger. Thus, there is no need for prior knowledge or trusted third parties apart from the distributed ledger. To prevent impersonation attacks, we require user interaction. It appears that, in some applications, the required user interaction is reduced in comparison to other user-assisted key-exchange protocols.