These solutions, however, introduce complexities such as the reliance on 64-bit integer arithmetic for handling amounts. In an effort to offer alternative approaches that avoid state-carrying covenants or extensive introspection while still providing functional benefits, a new method leveraging a specialized hash function has been proposed to enhance amount flexibility within CTV. This method does not require the addition of new template types in the style of TXHASH, thereby sidestepping the associated advantages and disadvantages.

The proposal introduces two additional opcodes to augment OP_CHECKTEMPLATEVERIFY: OP_TEMPLATEHASH and OP_INPUTAMOUNTS. The OP_TEMPLATEHASH opcode generates a CTV template hash from stack items, iterating through inputs and outputs. On the other hand, OP_INPUTAMOUNTS, which is exclusive to Taproot, calculates the sum of input amounts based on a provided parameter, offering various functionalities depending on the parameter's value. This opcode enables more sophisticated contracts, such as those allowing the combination of UTXOs locked by the same script for withdrawals from Vault contracts to staging addresses, facilitating operations with any amount UTXOs and enabling endogenous fee payments and change address registrations.

This approach, documented in a shared gist, credits several contributors to the development of these ideas, including Jeremy Rubin, James O'Beirne, and Salvatore Ingala, among others who have explored covenant design and specifically CTV. Their work underpins the solutions provided, aiming to mitigate the complexities and limitations encountered with existing methods, thus broadening the applicability and functionality of CTV in blockchain programming and contract design.