Quote from: DannyHamilton on July 09, 2017, 08:13:44 PM

Quote from: achow101 on July 09, 2017, 06:19:14 PM

It's important to note that only input scripts containing pushes are standard.

Interesting. How does P2SH work then? Isn't it necessary to provide OP codes in the input?

It's actually horribly hacky (and I didn't realize this until I read the code).

The redeemscript is actually a blob of data which is pushed to the stack first. Once the script (input and output script, no redeemscript) is interpreted once, the verifier checks if the scriptPubKey was a P2SH script (of the form OP_HASH160 OP_EQUAL). If it is, it pops the first item from the stack (which will be the redeemscript) and interprets that as a script and runs it. So the input script only consists of pushes since the redeemscript is really just a push of X bytes and is only later actually treated as a script.