diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 55c3d4b..2ceb0cc 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -190,7 +190,7 @@ Commonly used key flags include:
 - **Certification**: enables issuing third-party certifications
 - **Signing**: allows the key to sign data
 - **Encryption**: allows the key to encrypt data
-- **Authentication**: primarily used for OpenPGP authentication
+- **Authentication**: primarily used for SSH authentication
 
 ```{note}
 Distinct component keys handle specific operations. Only the primary key can be used for certification, although it can have additional capabilities. Subkeys can be used for signing, encryption, and authentication but cannot have the certification capability. It is considered good practice, however, to [use separate keys for each capability](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-12.html#section-10.1.5-7).