Script Challenges

The lock expects a specific number. Can you push the right one?

Push two numbers that add up to 9.

Push one number. The lock duplicates it and adds both copies. Result must be 10.

A nested IF/ELSE: two booleans select one of four outcomes (2, 3, 4, or 5). The lock checks for 4. Which two booleans open the path that pushes 4?

Push two numbers A and B. The lock swaps them, subtracts (B − A), verifies the result is positive, then checks it equals 3.

Push two identical numbers. The lock duplicates the top, copies the second (OP_OVER), verifies they match, then adds the two originals. Sum must be 8.

Find the preimage. The lock hashes your input with HASH160 (RIPEMD160(SHA256(x))) and checks the digest — the same hash used in Bitcoin addresses.

Push one number. The lock checks it is in the range [3, 10) (≥ 3 and < 10), then multiplies it by 2. The result must equal 10.

The lock has two paths: IF checks SHA256(preimage), ELSE checks HASH160(preimage). We want the ELSE path. Push the preimage and the boolean that selects ELSE.

Push two byte strings that concatenate to "helloworld" (hex: 68656c6c6f776f726c64). OP_CAT is restored on BSV.

Push two numbers. One goes to the alt stack, the other is doubled, then the alt value is added. Result must be 11.

Verify a Rabin signature: the lock computes s² mod n and checks it equals 4. Public key n = 77 (0x4d). Find a valid signature s.

The lock requires two different SHA256 preimages. The first (top of stack) must hash to one digest, the second to another. Push both in order.

Push one 10-byte value. The lock splits it at position 5 (OP_5 OP_SPLIT), then verifies the left half is "hello" and the right half is "world".

Push exactly three numbers. The lock verifies stack depth is 3 (OP_DEPTH), then adds all three. The sum must equal 12.

The lock concatenates two fields (sender and message) with OP_CAT, hashes with SHA256, and checks the digest. Find a valid [sender, message] pair that matches the locked hash.

Same lock as Two Paths: IF = SHA256(preimage), ELSE = HASH160(preimage). This time we want the IF path. Push the preimage and the boolean that selects IF.