> So my first shot at this is to go through the inputs of a transaction and > see if the scriptSig field has only two opcodes. If that is the case, I > assume that it is of the structure <sig> <pubKey> and calculate the > Bitcoin address from <pubKey>. > But then I started to wonder if this is safe. Can this be tricked somehow?
Sure. There are lots of non-standard scriptPubKey scripts that will validate if given <sig> <pubKey> as input: a simple OP_NOP would work (do nothing, then check the top value on the stack and validate if it is not zero-- and <pubKey> is not zero). If you assume the client has all previous transactions, then you could get the transaction input's prevout (from the memory pool or disk) and then ExtractAddress() from it. That is probably a bad idea for listtransactions, since fetching all the previous inputs from disk just so you can check to see if they're 'green' violates the "a feature shouldn't cost anything if it is not being used" design principle. You know, just thinking out loud... Green addresses could be implemented as a second signature in the scriptSig. You'd have to hack your bitcoin client, but you could generate a transaction that had <greensig> <sig> <pubKey> ... as the input instead of <sig> <pubKey>. The <greensig> will be ignored by old clients. The transactions is still considered 'standard'. But you could teach bitcoin to look for <greensig> signatures in wallet transactions... -- -- Gavin Andresen ------------------------------------------------------------------------------ The demand for IT networking professionals continues to grow, and the demand for specialized networking skills is growing even more rapidly. Take a complimentary Learning@Cisco Self-Assessment and learn about Cisco certifications, training, and career opportunities. http://p.sf.net/sfu/cisco-dev2dev _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
