Replace ch10 diags with svgs

book/source/10-encryption.md

@@ -107,7 +107,7 @@ In this version of the SEIPD packet, the session-key is used directly as message
 
 When communicating with a mix of recipients, some of whose OpenPGP software only supports OpenPGP version 4, then this mechanism must be used.
 
-```{figure} drawio/SEIPDv1-PKESK.png
+```{figure} drawio/SEIPDv1-PKESK.svg
 :name: fig-encryption-seipdv1-pkesk
 :alt: Depicts a dotted hexagon labeled "Plaintext", from which a curved arrow passes another dotted hexagon "Session Key" and finally points to a "SEIPDv1" packet. Two more curved arrows originate from the session key and pass Alice' and Bob's encryption key, ending in two PKESK packets.
 
@@ -127,7 +127,7 @@ In version 2 SEIPD, the *session key* is transformed into a *message key*, based
 The session-key can use a different symmetric algorithm than the message-key.
 ```
 
-```{figure} drawio/SEIPDv2-PKESK.png
+```{figure} drawio/SEIPDv2-PKESK.svg
 :name: fig-encryption-seipdv2-pkesk
 :alt: TODO