The Challenges of Compiling for Bitcoin

Turning high-level code into Bitcoin script is particularly challenging. Bitcoin’s scripting language is not like typical programming languages; it’s limited, not “Turing complete” (meaning it can’t handle all types of computations), and has strict limits on space. This makes translating even simple programs a lot more complex than it would be on other blockchains, like Ethereum.

For example, let’s revisit our Groth16 Verifier. In its high-level form, it’s just a few hundred lines of code. But when we compile it down to Bitcoin script, it explodes in size—potentially taking up millions of lines of Bitcoin script code and several gigabytes in memory! This is a huge problem, especially considering that Bitcoin’s blocks are limited to 4 megabytes each. Trying to fit something this large into Bitcoin’s script language is akin to trying to fit an elephant into a small car—the sheer size and complexity make it unfeasible under current network constraints. This massive size and verbosity make BitVM programs impractical without serious adjustments.