Linq

Non-Custodial Solana Wallet Infrastructure with MPC-Based Transaction Signing

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Linq is a non-custodial wallet backend built on Rust, using Axum and Solana Web3 to handle authenticated swaps, transfers, and balance operations.
It integrates with Jupiter for quote generation and swap execution, while using MPC and Threshold Signature Schemes (TSS/DKG) to distribute signing authority across nodes — ensuring no single party ever holds the complete private key.

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Highlights

⚙️ Component	💡 Description
Non-Custodial Signing	Implements MPC + TSS/DKG for distributed signing across nodes.
Secure Swap Execution	Fetches quotes and executes swaps via Jupiter’s APIs.
Authenticated REST API	Axum-based backend secured with JWT.
Persistent State	PostgreSQL-backed data store with Yellowstone RPC–powered Solana indexer.
Keyless Infrastructure	Private keys never exist in full; signing is threshold-based.

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System Architecture

Linq ├── backend/ # Axum REST API: auth, swaps, transfers, balances ├── indexer/ # Yellowstone RPC stream listener & on-chain event indexing ├── mpc/ # Multi-party computation & distributed signing modules ├── store/ # PostgreSQL ORM and persistence layer ├── migrations/ # Database schema migrations ├── Cargo.toml └── Cargo.lock

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Core Flow

🔸 Swap Flow

1. User authenticates and requests a quote → Linq → Jupiter Quote API
2. If accepted, Linq requests a swap transaction from Jupiter.
3. Nodes in the MPC network partially sign the transaction.
4. Once threshold is met, Linq finalizes the signature and submits it to Jupiter for execution.

🔸 Transfer Flow

1. User requests a transfer via authenticated REST endpoint.
2. Linq constructs and partially signs the transaction using distributed key shares.
3. Once quorum is reached, the signed transaction is broadcast to Solana.

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⚙️ Tech Stack

• Rust + Axum
• MPC / TSS / DKG
• Solana Web3 SDK
• Jupiter Aggregator API (quotes + swaps)
• JWT (authentication)
• PostgreSQL (state storage)
• Yellowstone RPC (on-chain event indexing)

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Vision

Linq is building the cryptographic foundation for keyless Solana transactions — enabling secure, distributed signing for swaps and transfers without ever exposing private keys.

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