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Server Reference Implementation

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Overview

This document provides a reference implementation guide for ATH protocol servers. Developers can use this as a basis to implement complete server functionality.

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Core Modules

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1. Identity Management Module

Responsible for managing the server DID identity and public/private key pairs: 
class IdentityManager:
    def __init__(self):
        self.did = None
        self.private_key = None
        self.public_key = None
    
    def load_identity(self, file_path):
        # Load identity information from a file
        pass
    
    def sign(self, data):
        # Sign data using the private key
        pass
    
    def verify_signature(self, public_key, data, signature):
        # Verify client signature
        pass

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2. Authorization Confirmation Module

Responsible for confirming authorization requests with the user: 
class AuthorizationConfirmation:
    def __init__(self):
        self.notification_channels = ["sms", "email", "app_push"]
    
    def send_confirmation_request(self, user_id, client_info, scopes):
        # Send an authorization confirmation request to the user
        pass
    
    def verify_confirmation_response(self, response):
        # Verify the signature of the user's confirmation response
        pass
    
    def get_authorization_result(self, request_id):
        # Query the user authorization result
        pass

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3. Permission Management Module

Responsible for permission approval and access control: 
class PermissionManager:
    def __init__(self):
        self.permission_policies = {}
    
    def validate_scopes(self, requested_scopes, user_authorization):
        # Verify that the requested scopes are within the user's authorization range
        pass
    
    def apply_policies(self, scopes, client_info):
        # Apply security policies and adjust permission scope
        pass
    
    def generate_access_token(self, client_did, user_id, scopes, ttl):
        # Generate a signed access token
        pass

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4. Handshake Service Module

Responsible for implementing the complete handshake flow: 
class HandshakeService:
    def __init__(self, identity_manager, auth_confirmation, permission_manager):
        self.identity_manager = identity_manager
        self.auth_confirmation = auth_confirmation
        self.permission_manager = permission_manager
        self.sessions = {}
    
    def handle_handshake_request(self, request):
        # Handle client handshake request
        pass
    
    def handle_identity_proof(self, request):
        # Handle client identity proof
        pass
    
    def handle_scope_request(self, request):
        # Handle permission request
        pass
    
    def handle_key_negotiation(self, request):
        # Handle key negotiation
        pass
    
    def validate_access_token(self, token):
        # Validate access token validity
        pass

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Handshake Flow Implementation Example

# Initialize the server
identity_manager = IdentityManager()
identity_manager.load_identity("server_identity.json")
auth_confirmation = AuthorizationConfirmation()
permission_manager = PermissionManager()
handshake_service = HandshakeService(
    identity_manager, 
    auth_confirmation, 
    permission_manager
)
# Handle handshake request
@app.route('/ath/handshake', methods=['POST'])
def handshake_endpoint():
    request_data = request.get_json()
    response = handshake_service.handle_handshake_request(request_data)
    return jsonify(response)
# Handle business requests
@app.route('/api/<path:path>', methods=['GET', 'POST'])
def api_endpoint(path):
    token = request.headers.get('Authorization')
    if not handshake_service.validate_access_token(token):
        return jsonify({"error": "Invalid token"}), 401
    # Handle business request
    pass

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Security Best Practices

  1. Server private keys must be stored offline and must not be exposed in public network environments
  2. User authorization confirmation must use multi-factor authentication (MFA)
  3. All handshake requests must be rate-limited to prevent brute-force attacks
  4. Regularly audit authorization logs and promptly address any anomalous behavior