add missing info

ERCS/erc-7620.md

@@ -27,7 +27,9 @@ Furthermore, there's potential to implement governance mechanisms, such as DAO g
 
 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 and RFC 8174.
 
-Compliant contracts MUST implement the following interface:
+### Interface
+
+#### `IERC7620`
 
 ```solidity
 pragma solidity ^0.8.20;
@@ -158,6 +160,42 @@ interface IERC7620 {
 }
 ```
 
+The `registerServiceProvider(address serviceProvider)` function `MUST` be implemented as public or external.
+
+The `deregisterServiceProvider(address serviceProvider)` function `MUST` be implemented as public or external.
+
+The `authorizeServiceProvider(address serviceProvider, uint256 amount)` function `MUST` be implemented as public or external.
+
+The `revokeAuthorization(address serviceProvider)` function `MUST` be implemented as public or external.
+
+The `deductAuthorizedFunds(address user, uint256 amount, string calldata referenceId)` function `MUST` be implemented as public or external.
+
+The `authorizedAmount(address user, address serviceProvider)` function `MUST` be implemented as pure or view.
+
+The `isServiceProviderRegistered(address serviceProvider)` function `MUST` be implemented as pure or view.
+
+The `deposit(uint256 amount)` function `OPTIONAL` be implemented as public or external.
+
+The `withdraw(uint256 amount)` function `OPTIONAL` be implemented as public or external.
+
+The `remainingBalance(address user)` function `OPTIONAL` be implemented as pure or view.
+
+The `ServiceProviderRegistered` event `MUST` be emitted when a service provider is registered.
+
+The `ServiceProviderDeregistered` event `MUST` be emitted when a service provider is deregistered.
+
+The `AuthorizationUpdated` event `MUST` be emitted when authorization amount is updated.
+
+The `FundsDeducted` event `MUST` be emitted when funds are deducted.
+
+The `AuthorizationRevoked` event `MUST` be emitted when authorization is revoked.
+
+The `Deposited` event `OPTIONAL` be emitted when funds are deposited.
+
+The `Withdrawal` event `OPTIONAL` be emitted when when funds are withdrawn.
+
+The deposit and withdraw functions for users are `OPTIONAL` in implementation, as funds can be transferred directly from the user's account in real-time during the `authorizeServiceProvider` operation.  
+
 ## Rationale
 
 The primary motivation behind the Pre-Authorized Service Payment Protocol stems from the need for a more efficient and secure transaction mechanism between users and service providers within the Ethereum blockchain. While ERC-20's `approve` method provides a means to authorize fund usage, there's a recognition that the authorized funds could be put to better use.