specification/protocol/blockchain/script.md

Script

Bitcoin Cash transactions make use of a scripting language to authorize and secure transfers. While, colloquially, there is a tendency to refer to transactions as "sending" Bitcoin Cash to "an address", that is merely an abstraction. In fact, the only thing that permits the spending of existing UTXOs is the successful execution of a script. The only thing preventing the spending of newly created UTXOs is the difficulty of producing a successfully executing script. Through the use of cryptographic signatures and hash functions, such scripts are often designed specifically to be difficult to produce unless you are the intended spender of a given UTXO, though that need not necessarily be the case. For more information on how transactions are commonly secured, see Locking Script. For the purposes of this page, we will be focusing more on how the scripts are run, what they are capable of, and what limitations they have.

Script Execution

Scripts are executed using a stack-based memory model