The invention relates to distributed ledger technologies such as consensus-based blockchains. Computer-implemented methods for a self-replicating smart contract with termination condition are described. The invention is implemented using a blockchain network, which may be, for example, a Bitcoin blockchain. A first transaction to validate is received at a node in a blockchain network. The first transaction includes a first script that, as a result of being executed, causes the node to at least obtain a first set of field values of the first transaction, with the first set of field values including a third script, and obtain a second set of field values of a second transaction, with the second set of field values including a copy of the second script. A second transaction is obtained. The second transaction includes a second script that, as a result of being executed, causes the node to, as a result of determining that a termination condition is unfulfilled, at least obtain the third script from the first set of field values, and determine that the copy of the second script matches the third script. The first transaction is validated as a result of execution of the first script and the second script.