Asset bridging in TAC enables tokens to move seamlessly between TON and TAC EVM while maintaining supply integrity and user ownership. Unlike traditional bridges that create wrapped tokens, TAC’s bridging system is designed specifically for application-level interactions where assets flow naturally based on user intent rather than explicit bridging operations.

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Core Bridging Principles

TAC’s asset bridging system operates on fundamental principles that ensure security, maintain token economics, and provide seamless user experience.
Asset bridging lock-mint and burn-release diagram

Asset bridging maintaining token supply integrity across chains

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Supply Conservation

  • Total Supply Integrity: The combined supply of a token across both TON and TAC EVM always equals the original supply. When tokens are locked on one chain, equivalent amounts are minted on the other chain, maintaining perfect balance.
  • Provable Reserves: All locked tokens are held in verifiable smart contracts where their existence can be independently confirmed by anyone.
  • Atomic Operations: Asset locking, minting, burning, and releasing operations occur atomically within the same cross-chain transaction, preventing inconsistent states.

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Bidirectional Flow

Assets can move in both directions depending on user operations and application requirements:

TON → TAC EVM

Lock-and-Mint Process
  • TON tokens locked in TON Adapter
  • Equivalent ERC-20 tokens minted on TAC EVM
  • Metadata preserved across chains
  • User maintains full ownership

TAC EVM → TON

Burn-and-Release Process
  • ERC-20 tokens burned on TAC EVM
  • Original tokens released from lock
  • User receives back on TON
  • Perfect 1:1 correspondence maintained

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Token Types and Handling

Different types of assets require specialized handling to ensure proper representation and functionality across both chains.

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TON Native Assets

  • Jetton Bridging: TON jettons (fungible tokens) are the most common bridged assets. When first crossing to TAC EVM, the system automatically deploys corresponding ERC-20 contracts.
  • Metadata Preservation: Token name, symbol, decimals, and additional metadata are captured from the TON side and replicated in the EVM contract.
  • Address Mapping: The system maintains deterministic mapping between TON jetton addresses and their corresponding ERC-20 addresses on TAC EVM. 
// Bridging a TON jetton
const assets = [{
  address: "EQTokenAddress...", // TON jetton address
  amount: 100.5,                // User-friendly amount
  decimals: 9                   // TON standard decimals
}];

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TAC EVM Native Assets

  • EVM-Origin Tokens: Tokens originally created on TAC EVM can also be bridged to TON, creating jetton representations on the TON side.
  • Liquidity Pool Tokens: LP tokens from DEXes and other DeFi protocols on TAC EVM can be bridged to TON for use in TON-native applications.
  • Governance Tokens: TAC-native governance tokens can be bridged to enable participation in governance from TON wallets.

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Bridging Mechanisms

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Lock-and-Mint Process

When assets move from TON to TAC EVM, they undergo a structured locking and minting process:

Asset Locking

User tokens are locked in the TON Adapter smart contracts on the TON side. These contracts serve as verifiable reserves where locked tokens remain until they’re bridged back.

Validation

Sequencers validate that the correct amount and type of tokens have been locked, ensuring the bridging request matches actual asset transfers.

Token Deployment

If this is the first time a particular token crosses to TAC EVM, the system automatically deploys a corresponding ERC-20 contract with matching metadata.

Minting

The exact amount of locked tokens is minted on TAC EVM and transferred to the appropriate address (either the user directly or a proxy contract for further operations).

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Burn-and-Release Process

The reverse process handles assets moving from TAC EVM back to TON:

Asset Burning

ERC-20 tokens on TAC EVM are burned, permanently removing them from circulation on that chain.

Consensus Validation

Sequencers verify the burn operation and confirm that the requesting user has proper authorization for the operation.

Release Execution

The corresponding amount of originally locked tokens is released from the TON Adapter contracts.

Delivery

Released tokens are delivered to the user’s TON wallet, completing the round-trip bridging process.

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Address Calculation and Mapping

TAC maintains deterministic relationships between token addresses across chains, enabling predictable bridging behavior.

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Deterministic Address Generation

  • TON to EVM Mapping: When a TON jetton first crosses to TAC EVM, its corresponding ERC-20 address is calculated based on the jetton’s metadata and TON address.
  • EVM to TON Mapping: Similarly, EVM tokens bridging to TON receive deterministic jetton addresses based on their EVM metadata.
  • Pre-Calculation: Applications can calculate paired addresses before tokens actually bridge, enabling advanced features like showing expected addresses in user interfaces.

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Address Registry

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Decimal and Precision Handling

Different blockchain ecosystems use different decimal standards, requiring careful handling to maintain precision and user experience.

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Decimal Standards

TON Standard: TON jettons typically use 9 decimals, following the platform’s conventions for token precision.
EVM Standard: Ethereum and EVM chains commonly use 18 decimals, providing higher precision for complex DeFi operations.

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Precision Management

  • Preservation: When TON tokens (9 decimals) bridge to TAC EVM, they maintain their 9 decimal precision rather than being artificially inflated to 18 decimals.
  • Compatibility: TAC EVM supports tokens with various decimal counts, ensuring that bridged tokens work correctly with existing DeFi protocols.
  • User Interface: Applications display amounts using the appropriate decimal precision for user familiarity while handling the technical differences behind the scenes.
While TAC EVM supports 18-decimal tokens, bridging them back to TON may have limitations due to TON’s 9-decimal standard. Consider keeping high-precision tokens on the EVM side.

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Automatic Token Deployment

The bridging system includes automatic token deployment capabilities that reduce friction for first-time token bridging.

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Deployment Process

  • Metadata Extraction: When a token first crosses chains, the system extracts all necessary metadata including name, symbol, decimals, and description.
  • Contract Generation: A standard ERC-20 or jetton contract is automatically deployed with the extracted metadata.
  • Registry Update: The new token deployment is registered in the cross-chain address registry for future reference.

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Deployment Triggers

  • First Bridge Operation: Token contracts are deployed automatically when a user first bridges a particular token type.
  • Batch Deployment: Multiple token types can be deployed in a single operation when complex transactions involve multiple new tokens.
  • Permissionless Process: Anyone can trigger token deployment by bridging assets, making the system fully permissionless.

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Liquidity Management

Asset bridging enables sophisticated liquidity management strategies that benefit both ecosystems.

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Unified Liquidity Pools

  • Cross-Chain Liquidity: Tokens can flow between chains based on where liquidity is most needed, optimizing capital efficiency.
  • Arbitrage Opportunities: Price differences between chains create natural arbitrage opportunities that help maintain price consistency.
  • Protocol Integration: DeFi protocols can access liquidity from both ecosystems, increasing available capital and reducing slippage.

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Example: DEX Liquidity

When users provide liquidity to a DEX on TAC EVM using TON-origin tokens:

Token Bridging

TON tokens are automatically bridged to TAC EVM as part of the liquidity provision transaction.

Liquidity Addition

Bridged tokens are added to the DEX liquidity pool, creating trading opportunities for both TON and EVM users.

LP Token Generation

Users receive LP tokens representing their share of the pool, which can be used on either chain.

Cross-Chain Access

The same liquidity serves traders from both ecosystems, maximizing utilization and fee generation.

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Security Considerations

Asset bridging implements multiple security layers to protect user funds and maintain system integrity.

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Economic Security

  • Collateral Requirements: Sequencers stake significant collateral to participate in bridging validation, creating financial incentives for honest behavior.
  • Multi-Party Validation: Multiple independent sequencer groups must agree on bridging operations before execution.
  • Slashing Mechanisms: Provably incorrect bridging operations result in automatic collateral slashing.

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Technical Security

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Integration Patterns

Developers can integrate asset bridging into their applications using several common patterns.

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Automatic Bridging

  • Transparent Operations: Users specify what they want to do (swap, provide liquidity, etc.) and the system automatically bridges required assets.
  • Single Transaction: From the user’s perspective, asset bridging and the target operation happen in a single transaction.
  • Status Updates: Applications can provide real-time updates on both bridging progress and target operation execution.

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Manual Bridging

  • Explicit Control: Some applications allow users to explicitly bridge assets before performing operations.
  • Batch Operations: Users can bridge multiple assets in preparation for complex operations.
  • Advanced Features: Manual bridging enables advanced features like pre-positioning assets for better execution.

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What’s Next?

Understanding asset bridging provides the foundation for exploring how complete transactions flow through TAC’s cross-chain system.

Transaction Lifecycle

Learn how bridging fits into the complete transaction flow

Message Validation

Understand how the system ensures bridging security