> Once you lose a master key, blockchain or no blockchain, your identity splits. The person who stole your key can impersonate you perfectly.
I agree that there is a race between you broadcasting your revocation and the attacker using your key. Until all relevant parties receive your revocation, your attacker impersonates you perfectly.
However, using the blockchain as a broadcast medium for revocations places an upper bound on how soon your revocation will received by the rest of the these parties (assuming the blockchain itself remains available during the compromise). This is not the case with existing PKI systems, which make no such provisions at the protocol level beyond a simple (and usually optional) key expiration. Moreover, the fact that blockchains are extremely difficult to convincingly forge means that your well-formed revocation transaction would be hard to censor in a way that you could not detect, so an unavailability attack would not leave you falsely believing that your revocation has been sent.
I agree that there is a race between you broadcasting your revocation and the attacker using your key. Until all relevant parties receive your revocation, your attacker impersonates you perfectly.
However, using the blockchain as a broadcast medium for revocations places an upper bound on how soon your revocation will received by the rest of the these parties (assuming the blockchain itself remains available during the compromise). This is not the case with existing PKI systems, which make no such provisions at the protocol level beyond a simple (and usually optional) key expiration. Moreover, the fact that blockchains are extremely difficult to convincingly forge means that your well-formed revocation transaction would be hard to censor in a way that you could not detect, so an unavailability attack would not leave you falsely believing that your revocation has been sent.