Chapter 5 assessment 2

1. In the ‘optimised OP_PUSH_TX', what process can be used to ensure that your input's script will generate a valid signature?

   • You can modulate the output

   • You can adjust nLocktime

   • You can change its sequence value

   • Any of the above <-

2. What SIGHASH flag must be used when using OP_PUSH_TX in a script?

   • SIGHASH_ALL

   • SIGHASH_SINGLE

   • SIGHASH_NONE | SIGHASH_ANYONECANPAY

   • It doesn't matter as long as the pre-image is formatted correctly <-

3. What did nodes need to change in the Bitcoin protocol to enable OP_PUSH_TX

   • They needed to change the signature message format

   • They needed to add the OP_PUSH_TX opcode

   • They needed to create a special queue to receive transactions that use OP_PUSH_TX

   • They didn't need to do anything as this is part of the native functionality of Bitcoin <-

4. How can you tell if you are using the official version of OP_PUSH_TX

   • There is a website where you can check

   • Nodes will warn you if you are not

   • There is no official version <-

   • It's baked into the OP_PUSH_TX opcode