diff --git a/firefox_addon/README.md b/firefox_addon/README.md
index ecd977b..579c940 100644
--- a/firefox_addon/README.md
+++ b/firefox_addon/README.md
@@ -32,7 +32,7 @@ The two columns in database are "login" and "password".
 login is compounded by "@@domain;login" encrypted with AES 256
 password is salted and encrypted with AES 256
 
-The key that encrypt these fields is PKBDF2(hmac-sha256, masterkey, password_server_url, 1000, 256)
+The key that encrypt these fields is PBKDF2(hmac-sha256, masterkey, password_server_url, 1000, 256)
 
 For now the only addons made is for firefox. Server side is written in PHP (with SQLite3 for database component).