For ArS3nal, we needed a solution written in Rust that avoided these shortcomings while remaining fully compatible with the existing ecosystem. This was difficult for several reasons:

• •No Formal Specs: We had to build without formal specifications or interoperability tests.
• •Non-Standard Crypto: Aspects of Arweave's use of cryptography deviate from standards and required precise handling.
• •L2 Complexity: To guarantee maximum compatibility, we needed comprehensive support for L2 (Bundles).

This allowed us to use Rust's type system to build an API that is idiomatic and hard to misuse. We moved most correctness checks to compile time to prevent runtime errors or—even worse—data corruption. Our architecture relies on:

• •Unrepresentable Invalid States: We used the type system to ensure invalid states cannot exist in the code.
• •Strict Access Control: We allow only specific, "blessed" methods for instantiating or converting certain types.
• •The Typestate Pattern: We used the typestate pattern to enforce the correct order of operations and safe state transitions.
• •Integrated Authentication: We treated data authentication as a core requirement enforced by the type system, not an afterthought.
• •Guarded Secrets: We placed key material behind specific "guard types." This prevents accidental disclosure and makes interaction with sensitive data intentional and easier to audit.