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+---
+title: End to End Message Authenticity in Cloud Native Systems
+weight: 9
+tags:
+ - rejekts
+ - security
+---
+
+<!-- {{% button href="https://youtu.be/rkteV6Mzjfs" style="warning" icon="video" %}}Watch talk on YouTube{{% /button %}} -->
+
+## Why does e2e authenticity matter?
+
+- Classic Setup: Micro-Services with TLS and auth via Bearer
+  ```mermaid
+  graph LR
+      User-->|TLS|Gateway
+      Gateway-->|mTLS|Server
+      Server-->|mTLS|Gateway
+      Gateway-->|TLS|User
+  ```
+- Intrusion: Hacked Gateway
+    - Can modify the request
+    - Could log auth tokens
+    - Could replay requests with different body or token
+
+
+## Baseline OIDC
+- Only IDP has private key for signing
+- Anyone can fetch the private key and verify
+- Usage: SSO, Trust Federation
+- Problem: Symmetric Credential can be forwarded if leaked
+
+## Fixes
+
+### HTTP Message Signatures
+
+- Idea:
+    - Client can sign the content and headers with a symmstric/asynmetric key
+    - Server can verify the signature
+- Implementation: Basicly just an additional Signature Header and a Header that tells us what is included in the signature
+  ```
+  HTTPS POST /test
+  Authorization: Bearer <token>
+  Signature-Input: "authorization" @body
+  Signature: ahsz7d9zahbsdoih
+  ```
+- Problem: Key distribution
+- Real-World: AWS v4 Signature shares accesskey and secretkey out of band and signs header with accesskey (symmatric)
+- Transitive Trust
+
+### OIDC Key binding
+
+TODO: Steal image from slides
+
+### Proof of Posession
+
+> Basicly adds a nonce that we have to sign and the idp now knows that we really posess it
+
+TODO: Steal image from Slides
+
+### OpenPubKey
+
+> Assigns meaning to the nonce and can reconstruct the nonce for a reverse check
+
+## Demo
+
+The demo uses GitHub as a PKI (since all public keys get exposed via github).
+Pretty cool: They automated the demo via a go cli.
+
+TODO: Link to demo code
+TODO: Steal image from Slides
+
+## Next steps
+
+- SPIFFE is the de-facto standard for distributing identities to workloads
+    1. Workloads asks "Who am I"
+    2. Agent attests the workload
+    3. Agent provides OIDC or X.509 to Workloads
+
+* WIMSE RFC: Basicly DPoP/OpenPub
+    1. Workload get's a private key
+    2. Issuer binds workload identity to the public key
+    3. Auth trusts SPIFFE, it can trust the key
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