Here are my latest thoughts on a safer OP_EVAL alternative, inspired by all the ideas and agitated IRC and email discussions of the last week or so:
Goal: Let users publish a short "funding address" that is the hash of an arbitrary redemption Script revealed when they spend the funds, implemented in a backwards-compatible-in-the-blockchain way. Proposal: A new 'standard' transaction type, "pay to Script hash": scriptPubKey: HASH160 <push-20-byte-hash> EQUAL Redeemed with the same scriptSig as the OP_EVAL proposal: <signatures> <serialized Script> Old clients/miners will ignore <signatures> and just validate that the hash of <serialized Script> matches. New clients/miners will recognize the new type of transaction and will do the following additional validation: 1. Fail validation if there were any operations other than "push data" in the original scriptSig. 2. Deserialize the top (last) item on the scriptSig stack (fail validation if it fails to deserialize properly). 3. Run an additional validation on the deserialized script, using the remaining items on the scriptSig stack and the deserialized script as the scriptPubKey. --------------- As Amir said in IRC chat today, "the idea is a hack.... but I like it." I like it, too-- it is cleaner than OP_EVAL, more straightforward to implement, and pretty much exactly matches the feature I care about (moving code from the scriptPubKey to the scriptSig). There are no special cases like "CODESEPARATORS not allowed in <serialized script>". -- -- Gavin Andresen ------------------------------------------------------------------------------ Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
