diff --git a/book/source/17-zoom_certificates.md b/book/source/17-zoom_certificates.md
index 9a6a3cb..6ce27be 100644
--- a/book/source/17-zoom_certificates.md
+++ b/book/source/17-zoom_certificates.md
@@ -433,7 +433,7 @@ Should this text go elsewhere?
 
 The signature does more than just bind the subkey; it also carries additional metadata about the subkey. This metadata is in the binding signature, and not in the subkey packet, because it may change over time, while the subkey packet itself remains unchanged. This evolving metadata is stored in self-signatures: if the key holder wants to modify the metadata (for example, to change the key's expiration time), a newer version of the same signature type can be issued. The recipient OpenPGP software will recognize that the newer self-signature supersedes the older one, and that the metadata in the newer signature reflects the most current intent of the key holder.
 
-Note that this subkey binding signature packet is quite similar to the Direct Key Signature discussed above. Both signatures serve a similar purpose in adding metadata to a component key, particularly as the hashed subpacket data contains much of the metadata elements.
+Note that this subkey binding signature packet is quite similar to the Direct Key Signature discussed above. Both signatures serve a similar purpose in adding metadata to a component key, particularly as the hashed subpacket data contains much of the same metadata elements.
 
 ```text
 $ sq packet dump --hex alice.pub-5--Signature