Script Validation Checkpoint

Trace cursor and stack state, then inspect the exact signature commitment.

Get every question correct to pass this checkpoint. You can review feedback, revise your answers, and submit again.

1. Starting empty, execute hex 02 76 aa 76. What is the stack?

Select one answer.

Two copies of the literal bytes 76aa One hash of byte 76 A failed HASH256 on an empty stack The bytes 02 and 76

2. Hex 01 07 76 88 executes successfully. What is the evaluator result?

Select one answer.

True because equality always returns true True because DUP created a second item False because byte 07 is an opcode False because EQUALVERIFY leaves an empty stack

3. Invalid CHECKSIG inputs are followed by a push of 01. What does this course machine return?

Select one answer.

False: two stack items are forbidden True only if the public key is on curve True: final top is 01 False: every CHECKSIG failure halts

4. An EQUALVERIFY mismatch is followed by a push of 01. What happens?

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Only the top item is removed Execution fails before the push The later push makes it succeed The mismatch becomes 00 and execution continues

5. A valid signed transaction has an output changed, but tx.ID, index and locking bytes remain identical. Is signature failure guaranteed here?

Select one answer.

No; this digest uses the supplied ID without recomputing it Yes; the evaluator serializes outputs Yes; changing any struct field changes its ID automatically No; all signature digests ignore outputs

6. What four bytes represent inputIndex=258 in the preimage?

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00 00 01 02 32 35 38 00 01 02 00 00 02 01 00 00

7. Under this course rule, which final top item is false?

Select one answer.

01 80 00 00 00 00 80

8. A passing script result establishes which fact?

Select one answer.

The header has valid proof of work This supplied program ended truthy under the course rules The inputs are unspent on the selected chain The output values conserve funds

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