diff --git a/book/source/10-encryption.md b/book/source/10-encryption.md
index fb94540..bec0d55 100644
--- a/book/source/10-encryption.md
+++ b/book/source/10-encryption.md
@@ -31,3 +31,9 @@ Core concept:
 ### Implications of how a recipient cert is "addressed" (fingerprint/key-ID vs. user-ID) (preferences, expiration, revocation)
 
 ## Zooming in: Package structure and internals
+
+### Encryption yields a 'wrapped' openpgp packet stream
+
+### SKESK
+
+Also see https://flowcrypt.com/docs/guide/send-and-receive/send-password-protected.html
\ No newline at end of file