Delegate from WCF to an external, non-windows service

Question

We have a service that uses WCF and client credentials - when we communicate with other WCF services, we use delegation and it works relatively well.

However, now we are trying to integrate with a service written in Python / Linux - how can we redirect credentials from WCF to this Python service? Can we somehow create a signed statement that the Python service can verify? (Assume that the Python service has access to AD.)