OP_CAT Enables Winternitz Signatures

In the exploration of optimizing Bitcoin script for efficiency, a notable improvement has been identified in the use of OP codes to achieve more compact scripts. A transformative suggestion was made to substitute OP_DUP OP_ADD operations for OP_LSHIFT, which led to a significant reduction in byte usage. This strategy harnesses OP_SIZE to ascertain if the output from combined numbers exceeds 127, leveraging the fact that the interpreter's OP_ADD output is expected to manifest as a 2-byte value for outputs within the range of 128 to 255. This insight enables the elimination of SWAP/ROT operations, culminating in a reduction to 35 bytes per script iteration from the initial 58 bytes.

Further optimizations were achieved through meticulous scripting adjustments, resulting in an overall saving of 736 bytes across all script loops. Consequently, this optimization brought down the total script and witness size to approximately 7212 bytes, or equivalently, 1803 vbytes. The revised scripting approach not only streamlines the process but also enhances the efficiency of the implementation.

An updated version of the bitshift code, complemented with detailed comments, has been shared for further review and application. The modifications present a significant leap forward in scripting efficiency and are documented for accessibility and community feedback at this gist. This initiative underscores the collaborative effort and continuous innovation within the Bitcoin development community, contributing to the refinement and advancement of Bitcoin scripting capabilities.