Type Definitions

Payment Requirement

Returned by server in 402 response.

interface FHEPaymentRequirement {
  scheme: 'fhe-transfer';
  network: string;
  chainId: number;
  payTo: `0x${string}`;
  maxAmountRequired: string;
  asset: `0x${string}`;
  resource: string;
  description: string;
  mimeType: string;
  maxTimeoutSeconds: number;
  facilitator?: string;
}

Field	Type	Description
scheme	string	Always 'fhe-transfer'
network	string	Network name (e.g., 'sepolia')
chainId	number	Chain ID (e.g., 11155111)
payTo	address	Merchant address
maxAmountRequired	string	Required amount in token decimals
asset	address	ERC7984 token contract
resource	string	Protected resource URL
description	string	Human-readable description
mimeType	string	Content type of resource
maxTimeoutSeconds	number	Payment timeout
facilitator	string	Optional facilitator URL

---

Decryption Signature

User authorization for server-side decryption.

interface FHEDecryptionSignature {
  signature: string;
  publicKey: string;
  privateKey: string;
  userAddress: `0x${string}`;
  contractAddresses: `0x${string}`[];
  startTimestamp: number;
  durationDays: number;
}

Field	Type	Description
signature	string	Wallet signature
publicKey	string	Ephemeral public key
privateKey	string	Ephemeral private key
userAddress	address	User's Ethereum address
contractAddresses	address[]	Authorized contracts
startTimestamp	number	Unix timestamp
durationDays	number	Validity period

The privateKey is ephemeral, not the user's wallet key.

---

Payment Payload

Sent by client after transfer.

interface FHEPaymentPayload {
  x402Version: 1;
  scheme: 'fhe-transfer';
  network: string;
  chainId: number;
  payload: {
    txHash: `0x${string}`;
    decryptionSignature: FHEDecryptionSignature;
  };
}

Field	Type	Description
x402Version	number	Always 1
scheme	string	Always 'fhe-transfer'
network	string	Network name
chainId	number	Chain ID
payload.txHash	string	Transfer transaction hash
payload.decryptionSignature	object	Decryption authorization

---

Verify Result

Response from facilitator verification.

interface FHEPaymentVerifyResult {
  isValid: boolean;
  invalidReason?: string;
  txHash?: `0x${string}`;
  amount?: string;
}

Field	Type	Description
isValid	boolean	Payment validity
invalidReason	string	Error explanation
txHash	string	Verified transaction
amount	string	Decrypted amount

---

ConfidentialTransfer Event

ERC7984 transfer event data.

interface ConfidentialTransferEvent {
  from: `0x${string}`;
  to: `0x${string}`;
  amount: `0x${string}`;
}

Field	Type	Description
from	address	Sender
to	address	Recipient
amount	bytes32	Encrypted handle

The amount field is an encrypted handle, not the actual value.