Security

T402 is designed with security as a core principle. This section documents the cryptographic foundations, threat model, and security audit scope for the protocol.

T402 is preparing for a formal security audit. This documentation is designed to assist auditors and security researchers in understanding the protocol’s security properties.

Security Documentation

Document	Description
Cryptographic Operations	Complete documentation of all cryptographic algorithms, signature schemes, and key management across all supported blockchains.
Threat Model	Analysis of trust assumptions, in-scope threats, attack vectors, and mitigation strategies.
Audit Scope	Detailed scope document for security auditors including critical code paths, testing recommendations, and focus areas.

Security Principles

1. No Custom Cryptography

T402 uses only industry-standard cryptographic primitives:

Chain Family	Signature Algorithm	Hash Function	Standard
EVM	ECDSA (secp256k1)	Keccak-256	EIP-712, EIP-3009
Solana	Ed25519	SHA-512	Solana standard
TON	Ed25519	SHA-256	TON TL-B
TRON	ECDSA (secp256k1)	SHA-256	TRON protocol
NEAR	Ed25519	SHA-256	NEP-141
Aptos	Ed25519	SHA3-256	Fungible Asset
Tezos	Ed25519/secp256k1/P256	Blake2b	FA2 (TZIP-12)
Polkadot	Sr25519/Ed25519	Blake2b	Asset Hub
Stacks	ECDSA (secp256k1)	SHA-256	SIP-010
Cosmos	ECDSA (secp256k1)	SHA-256	Bank MsgSend

2. Defense in Depth

Multiple layers of protection prevent unauthorized payments:

┌─────────────────────────────────────────────────────────────┐
│                    TRANSPORT LAYER                          │
│  HTTPS/TLS encryption for all communication                │
├─────────────────────────────────────────────────────────────┤
│                    PROTOCOL LAYER                           │
│  EIP-712 typed data prevents signature reuse               │
├─────────────────────────────────────────────────────────────┤
│                    APPLICATION LAYER                        │
│  Nonces, time windows, amount validation                   │
├─────────────────────────────────────────────────────────────┤
│                    BLOCKCHAIN LAYER                         │
│  Smart contract verification, finality guarantees          │
└─────────────────────────────────────────────────────────────┘

3. Minimal Trust Requirements

Entity	Trust Level	Reason
Blockchain	High	Protocol security depends on blockchain consensus
Token Contracts	High	USDT/USDC contracts must function correctly
Facilitator	Medium	Can be self-hosted; cannot forge signatures
Resource Server	Low	Cannot access funds without valid signature
Client	None	Signatures are cryptographically verified

4. Fail-Safe Design

Invalid signatures are rejected before any funds move
Insufficient balance checks occur before settlement
Time windows prevent indefinite authorization validity
Nonce registry prevents double-spending

Security Features by Chain

EVM Networks

Feature	Implementation
Replay Protection	EIP-712 domain separator (chainId, verifyingContract)
Authorization	EIP-3009 TransferWithAuthorization
Nonce Management	32-byte random nonce, on-chain registry
Time Bounds	validAfter / validBefore timestamps
Smart Wallets	EIP-1271 signature verification
Counterfactual	ERC-6492 wrapped signatures

Solana (SVM)

Feature	Implementation
Replay Protection	Recent blockhash (300 blocks validity)
Authorization	TransferChecked instruction
Fee Payer Safety	Instruction structure validation
Amount Validation	Exact amount matching

TON

Feature	Implementation
Replay Protection	Wallet seqno (sequence number)
Authorization	Jetton transfer message
Address Derivation	Owner + Jetton master validation

TRON

Feature	Implementation
Replay Protection	Reference block + expiration
Authorization	TRC-20 transfer
Address Recovery	ECDSA public key recovery

Reporting Security Issues

If you discover a security vulnerability, please report it responsibly:

Email: security@t402.io
Do not disclose publicly until patched
Include detailed reproduction steps
We will acknowledge within 48 hours

⚠️

Never share real private keys or sensitive credentials when reporting issues. Use testnet funds and test accounts only.

Security Audit Status

Component	Status	Auditor
Smart Contracts (T402UptoRouter)	Internal audit complete (0 Critical, 2 Medium)	External audit pending
Protocol Specification	Internal review complete	External audit planned Q2 2026
Facilitator Service	Internal review complete	External audit planned Q2 2026
TypeScript SDK	Internal review complete	External audit planned Q2 2026
Go SDK	Internal review complete	External audit planned Q2 2026
Python SDK	Internal review complete	External audit planned Q2 2026
Java SDK	Internal review complete	External audit planned Q2 2026

Resources

Cryptographic Operations - Detailed crypto documentation
Threat Model - Security analysis and mitigations
Audit Scope - Auditor guidance
GitHub Security Policy - Vulnerability reporting

Cryptographic Operations