What signature verification opcodes does KIP-0017 add to Kaspa?

KIP-0017 introduces two new opcodes that let Kaspa scripts verify cryptographic signatures against an arbitrary 32-byte message hash held directly on the script stack. OpCheckSigFromStack (opcode 0xd7) checks a Schnorr signature by taking a signature, a 32-byte message hash, and a public key as inputs, then pushes a true-or-false result. OpCheckSigFromStackECDSA (opcode 0xd8) does the same thing for ECDSA signatures. An opcode is a single low-level instruction the network executes when deciding whether a transaction is valid — think of it as one step in a programmable lock that controls how coins can be spent. For developers, these opcodes matter because they allow scripts to sign and verify arbitrary data rather than only standard transaction hashes, which unlocks more sophisticated multi-party and contract-style logic on Kaspa.