AWS API Gateway提供了多种认证策略，包括以下几种常用的：

1. IAM认证：使用AWS Identity and Access Management (IAM)来控制对API的访问权限。可以通过在API Gateway中配置IAM角色和策略来实现认证。 代码示例：

import boto3

def create_api_gateway(api_name):
    client = boto3.client('apigateway')
    
    # 创建API
    response = client.create_rest_api(
        name=api_name,
        description='My API'
    )
    
    # 创建资源
    response = client.create_resource(
        restApiId=response['id'],
        parentId=response['rootResourceId'],
        pathPart='myresource'
    )
    
    # 创建方法
    response = client.put_method(
        restApiId=response['restApiId'],
        resourceId=response['id'],
        httpMethod='GET',
        authorizationType='AWS_IAM'
    )
    
    # 配置IAM授权
    response = client.put_integration(
        restApiId=response['restApiId'],
        resourceId=response['resourceId'],
        httpMethod=response['httpMethod'],
        type='AWS',
        integrationHttpMethod='GET',
        uri='arn:aws:apigateway:{region}:{subdomain}:{service}:{path}'
    )
    
    # 配置方法响应
    response = client.put_method_response(
        restApiId=response['restApiId'],
        resourceId=response['resourceId'],
        httpMethod=response['httpMethod'],
        statusCode='200',
        responseModels={'application/json': 'Empty'}
    )
    
    # 配置集成响应
    response = client.put_integration_response(
        restApiId=response['restApiId'],
        resourceId=response['resourceId'],
        httpMethod=response['httpMethod'],
        statusCode='200',
        responseTemplates={'application/json': ''}
    )
    
    # 部署API
    response = client.create_deployment(
        restApiId=response['restApiId'],
        stageName='prod'
    )
    
    # 获取API的URL
    response = client.get_deployments(
        restApiId=response['restApiId']
    )
    
    url = response['items'][0]['invokeUrl']
    
    return url

2. Lambda授权：使用AWS Lambda函数来认证API请求。可以将Lambda函数与API Gateway集成，并在函数中验证请求的有效性。 代码示例：

import json

def lambda_handler(event, context):
    # 解析请求
    method = event['httpMethod']
    path = event['path']
    
    # 验证请求
    if method == 'GET' and path == '/myresource':
        return {
            'statusCode': 200,
            'body': json.dumps({'message': 'Hello World!'})
        }
    else:
        return {
            'statusCode': 403,
            'body': json.dumps({'message': 'Forbidden'})
        }

3. Cognito用户池认证：使用Amazon Cognito用户池来管理API的用户认证和授权。可以在API Gateway中配置Cognito用户池来实现用户认证。 代码示例：

import boto3

def create_cognito_user_pool(user_pool_name):
    client = boto3.client('cognito-idp')
    
    # 创建用户池
    response = client.create_user_pool(
        PoolName=user_pool_name
    )
    
    # 创建用户池客户端
    response = client.create_user_pool_client(
        UserPoolId=response['UserPool']['Id'],
        ClientName='myclient'
    )
    
    # 创建用户
    response = client.sign_up(
        ClientId=response['UserPoolClient']['ClientId'],
        Username='myuser',
        Password='mypassword'
    )
    
    # 确认用户
    response = client.admin_confirm_sign_up(
        UserPoolId=response['UserPool']['Id'],
        Username='myuser'
    )
    
    # 获取用户凭证
    response = client.initiate_auth(
        AuthFlow='USER_PASSWORD_AUTH',
        AuthParameters={
            'USERNAME': 'myuser',
            'PASSWORD': 'mypassword'
        },
        ClientId=response['UserPoolClient']['ClientId']
    )
    
    access_token = response['AuthenticationResult']['AccessToken']
    
    return access_token

以上是AWS API Gateway的一些常用认证策略的代码示例，可以根据实际需求选择适合的认证方式。