Implement multi-sig capability tokens to flatten authorization hierarchies during complex asset fractioning

[Damola-Sodiq]

Description

Engineer a cryptographic capability token pattern to authenticate deep cross-contract calls without recursively checking signatures at every layer.

Architecture & Context

When a DAO authorizes a massive asset fractioning event, the transaction must pass through a proxy, a registry, and finally the token contract. Recursively calling env.auth() at every hop bloats the payload. Emitting a single-use capability token at the entry point flattens the authorization tree.

Technical Requirements

• Generate a secure, deterministic capability BytesN<32> hash that includes the transaction context and an expiration sequence.
• Validate this hash strictly at the deepest execution layer.
• Ensure capability tokens are completely invalid once the invoking ledger closes.

Acceptance Criteria

• Authorization payload sizes drop significantly.
• Cross-contract calls successfully validate the capability without native auth checks.
• Stolen or intercepted capability tokens cannot be replayed.

[samsolo247]

Hi Maintainer,

I’m a smart contract and full-stack developer and would love to contribute to this issue. I’m an experienced contributor with hands-on expertise in Rust, Soroban, Cairo, and TypeScript.

I’m passionate about building secure, scalable blockchain solutions, with a strong emphasis on writing clean and maintainable code. Based on the scope of this issue, I’m confident I can deliver a complete solution within 24 hours of assignment.

I’d greatly appreciate the opportunity to contribute and help move this forward.

[grantfox-oss]

🦊 GrantFox — @samsolo247 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #478)
2. Your PR will be reviewed by the Sahara-Pay maintainers

Good luck! Track your progress on GrantFox.