doc: mention bitSign code signing in main README

Signed-off-by: Richard Alpe <richard@bit42.se>

Author: rical

README.md

@@ -135,10 +135,16 @@ for reliability you can trust:
 - **Hardware Acceleration**: Linux switchdev support for wire-speed packet processing
 - **Container Integration**: Docker support with flexible network and hardware access
 - **Memory Efficient**: Runs comfortably on devices with as little as 256 MB RAM
+- **Code Signing**: All releases are cryptographically signed for integrity verification
 
 Perfect for everything from resource-constrained edge devices to
 high-throughput network appliances.
 
+<a href="https://bitsign.se">
+  <img src="https://bitsign.se/assets/badges/powered-by-bitsign-light.png#gh-light-mode-only" alt="Code signing powered by bitSign" width="250">
+  <img src="https://bitsign.se/assets/badges/powered-by-bitsign-dark.png#gh-dark-mode-only" alt="Code signing powered by bitSign" width="250">
+</a>
+
 > Check the *[Latest Build][]* for bleeding-edge features.
 
 ---