What is KIP-15 (Sequencing Commitment)?

KIP-15, called Sequencing Commitment, is a Kaspa protocol feature that embeds a recursive cryptographic hash chain into every block header, locking in the canonical ordering of all transactions from the very first block. In a blockchain, "canonical ordering" means the single agreed-upon sequence of all transactions — who sent what to whom, and in what order. By chaining each block's header to this ordering cryptographically, every new block carries a permanent, tamper-evident record of all prior transaction ordering, even if the raw block data itself has been pruned to save disk space. This matters for beginners because it means Kaspa's history is not something that can be quietly rewritten — any tampering would instantly break the hash chain and be visible to every node on the network.