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+# Questions
+
+> What can be said about privacy and confidentiality in blockchains? Which kind of identity privacy can be kept? Can data be kept confidential, and how?
+
+Because transactions are stored immutably in the blockchain, it is possible to see all previous interactions for a specific public key.
+If i where to use the same key for everything, that would not give me much privacy as my friends would probably also know that identity.
+
+If i want to keep my transactions private, i would have to make new identities for each purpose.
+This would require alot of managing of resources, as each identity has it's own wallet.
+
+
+> Is it possible to remove all the "transaction data" of a block from the disk, and keep only the Merkle tree head? In which cases?
+
+Yes it is possible, especially if all the money contained in it is spent.
+Because the hash of the block only covers the Merkle tree head, one can remove the rest from disk.
+
+However this is stupid if one want's to keep historical data of transactions.
+
+> Why is the miner protected from a "while(true) {...}" Denial of Service attach in Ethereum / Solidity?
+
+The program can't run forever before reaching the computation limit, which i think is galled gas.
+That way a while loop would quickly run out of gas, and the execution will stop.
+In that way it is only the owner of the contract who wastes their money.