title: Can I specify an AWS DynamoDB policy based on Cognito ID?
body: <p>Can I apply a policy to an AWS DynamoDB table but restrict it based on the Cognito ID of the user accessing it?</p>
  
  <p>E.g. A Customer table has a primary hash key equal to the Cognito ID. When anyone but the user sharing the same ID tries to get the item they will receive an unauthorised exception.</p>
  
  <p>(Non DynanoDB policies are probably also valid.)</p>