diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 7dcf1f3..36ea229 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -172,7 +172,7 @@ However, the owner of a certificate doesn't want a third party to add subkeys (o
 
 To prevent malicious addition of components, OpenPGP uses cryptographic signatures. These signatures show that components have been added by the owner of the OpenPGP certificate (these linking signatures are issued by the primary key of the certificate).
 
-So while anyone can still unilaterally store unrelated subkeys and [identity components](identity_components) in an OpenPGP certificate dataset, OpenPGP implementations that read this file should discard components that don't have a valid cryptographic connection with the certificate.
+So while anyone can still unilaterally store unrelated subkeys and [identity components](identity_components) in an OpenPGP certificate dataset, OpenPGP implementations that read this certificate should discard components that don't have a valid cryptographic connection with the certificate.
 
 (Conversely, it's easy for a third party to leave out packets when passing on an OpenPGP certificate. An attacker can, for example, choose to omit revocation packets. The recipient of such a partial copy has no way to notice the omission, without access to a different source for the certificate that contains the revocation packet.)