Unlocking Bitcoin’s Full Potential: Revisiting Truncated Opcodes for Innovation | by Michael P. Di Fulvio | The Capital | Jan, 2025

Bitcoin’s scripting language, while simple and functional, underwent significant changes in 2010. Several opcodes were removed or restricted, leading to a less expressive scripting environment. While these changes were necessary for security and performance, revisiting them with modern limits could unlock both old and new use cases, enhancing Bitcoin’s utility while preserving its robustness.

In its early implementation, Bitcoin included a variety of opcodes such as OP_ADD, OP_MUL, OP_CAT, OP_INVERT, and OP_LSHIFT. These opcodes allowed for more expressive scripting but came with inherent risks. Many lacked data limits, which could theoretically lead to exponential and unrestricted computational resource consumption. For example:

OP_CAT: Concatenated two stack elements.

OP_ADD and OP_MUL: Allowed arithmetic operations on stack elements.

The absence of data constraints presented vulnerabilities, such as the potential for creating infinite loops or denial-of-service attacks. To address these issues, certain opcodes like OP_CAT were removed entirely, while others were restricted to ensure security and scalability.