Are DAG-based crypto currencies as secure as proof-of-work based blockchains? A key feature of blockchain based cryptocurrencies is that they provide inherently secure systems that don't rely on third parties. The newer DAG-based cryptos like Byteball are being touted as superior to blockchains because they have faster transaction times and eliminate the need for miners. However, these cryptos use something called "trusted witnesses" to resolve double spend conflicts. Isn't this inherently less secure than a true trustless system like Proof of Work? I thought that the whole point of a blockchain was to provide intrinsic security without the need for trusted third parties.
You need to prove that the witness Selection process is random and independent. Alice can double-spent if she has control over the witness and the network.
Let assume Alice can double-spent, in bitcoin one can wait for 6 confirmations to rule out most of the double-spent. E.g. Seller only sends out the goods after 6 confirmation. How can you achieve this in DAG? since the account is only updated by its' own transaction. On top of that, the graph DAG is very complex compared to bitcoins' link-listed blockchain.
DOuble-spent transactions may get buried by other transactions.