📖 Overview & Quickstart

What is KAT Bridge?

KAT Bridge is a two-way trust-minimized bridge between:

  • Kasplex KRC-20 Protocol on Kaspa L1 (KRC-20 Inscriptions)

  • Kasplex EVM L2 (ERC-20 Smart Contracts)

It is developed and operated by the Kaspa Alliance for Transparency in collaboration with Zealous Swap.

KAT Bridge uses FROST threshold signatures for security: no single relayer can move funds. A quorum of independent relayers must cooperate to produce a valid bridge signature.

Why It Exists

  • Enable KRC-20 assets to participate in EVM-based DeFi on Kasplex Layer 2.

  • Provide a decentralized, transparent pathway for ERC-20 assets to return to Kaspa.

  • Demonstrate best-in-class bridging security via decentralized FROST multi-sig scheme.

  • Uphold K.A.T. Foundation’s mission: transparency, decentralization, accountability.

Supported Tokens

  • KRC-20 ↔ ERC-20: selected tokens (public list maintained in Supported Tokens).

  • NFTs (KRC-721 ↔ ERC-721) are out of scope for KAT Bridge currently but under development.

Safety Principles

  • 🔑 Threshold Security: funds cannot move without M-of-N FROST cooperation.

  • 🛑 Deposit-only EXTRA Blob: the EXTRA link mechanism is limited to deposits. Vault contracts never expose EXTRA.

  • ⏱ Finality Windows: relayers only act after confirmed blocks on both chains.

  • 📖 Transparency: signer set commitments, configs, and audits are public.

Quickstart (End Users)

1. Deposit (Kaspa → Kasplex)

  1. Send KRC-20 tokens to the bridge deposit address with the correct EXTRA blob.

  2. Your KRC-20 deposit transaction MUST be initiated from the KAT Bridge UI for the required EXTRA blob to be included and verified.

  3. Relayers detect and confirm the transaction.

  4. After quorum signature, the ERC-20 equivalent is minted on Kasplex L2.

2. Withdraw (Kasplex → Kaspa)

  1. Burn ERC-20 tokens on the L2 bridge contract.

  2. Relayers validate the burn and reach signature quorum.

  3. KRC-20 tokens are released on Kaspa L1.

High-Level Flow

flowchart LR
    A[KRC-20 Holder] -->|Deposit txn + EXTRA| B[Kaspa L1]
    B -->|Confirmed + Indexed| C[Relayers]
    C -->|FROST quorum sig| D[ERC-20 Bridge Contract]
    D -->|Mint tokens| E[User L2 Wallet]

Key Terms

  • Relayer: Independent service that observes both chains, contributes FROST shares, and executes bridging.

  • FROST: Flexible Round-Optimized Schnorr Threshold signatures; M-of-N multi-sig without a single private key.

  • EXTRA: Kasplex link blob commited on chain and used to encode deposit metadata.

Learn More

  • System Architecture → components and diagrams.

  • Security Model → how FROST and safeguards work.

  • Integration Guide → API, SDKs, and code examples.

Next🧠 System Architecture