An IAM policy in JSON format that is passed with the  CopyC#
CopyC#GetFederationToken
 CopyC#
CopyC#GetFederationToken
If you do not pass a policy, the resulting temporary security credentials have no effective permissions. The only exception is when the temporary security credentials are used to access a resource that has a resource-based policy that specifically allows the federated user to access the resource.
For more information about how permissions work, see Permissions for GetFederationToken in Using Temporary Security Credentials.
 Declaration Syntax
 Declaration Syntax| C# | 
public string Policy { get; set; }