diff --git a/book/source/06-signatures.md b/book/source/06-signatures.md
index 903ae7b..a4fcaa7 100644
--- a/book/source/06-signatures.md
+++ b/book/source/06-signatures.md
@@ -83,6 +83,7 @@ The signature packet consists of two parts:
 Creating a signature in OpenPGP
 ```
 
+(sig-verify)=
 ### Verifying an OpenPGP signature packet
 
 Verifying an OpenPGP signature packet is similar to its creation, with some crucial differences that facilitate the verification by entities other than the signer.