Certificate transparency only uses a blockchain if you redefine a blockchain to mean "any use of a merkle tree", which is all certificate transparency logs are.

Certificate transparency only uses a blockchain if you redefine a blockchain to mean "any use of a merkle tree", which is all certificate transparency logs are. You will notice the certificate transparency website makes zero mentions of blockchain anywhere: https://certificate.transparency.dev/howctworks/ https://certificate.transparency.dev/howctworks/ What a blockchain normally means is something that has added some sort of attempt at solving the two generals problem (https://en.wikipedia.org/wiki/Two_Generals%27_Problem https://en.wikipedia.org/wiki/Two_Generals%27_Problem), as the original bitcoin whitepaper outlined. That is to say, blockchains have a consensus mechanism to resolve multiple writers, with some of those being potentially untrusted. If Certificate Transparency is a blockchain, than so are the zfs filesystem (which also uses a merkle tree internally), git, and dynamodb.