diff --git a/book/source/03-cryptography.md b/book/source/03-cryptography.md
index 12cbb66..e5ff82d 100644
--- a/book/source/03-cryptography.md
+++ b/book/source/03-cryptography.md
@@ -3,7 +3,7 @@ SPDX-FileCopyrightText: 2023 The "Notes on OpenPGP" project
 SPDX-License-Identifier: CC-BY-SA-4.0
 -->
 
-(cyrptography_chapter)=
+(cryptography_chapter)=
 # Cryptographic concepts and terms
 
 ## Cryptographic hash functions