diff --git a/beaker/util.py b/beaker/util.py
index fcb9912..cf656a7 100644
--- a/beaker/util.py
+++ b/beaker/util.py
@@ -303,8 +303,8 @@ def coerce_session_params(params):
         ('id', (str,), "Session id must be a string."),
         ('key', (str,), "Session key must be a string."),
         ('secret', (str, NoneType), "Session secret must be a string."),
-        ('validate_key', (str, NoneType), "Session encrypt_key must be a string."),
-        ('encrypt_key', (str, NoneType), "Session validate_key must be a string."),
+        ('validate_key', (str, NoneType), "Session validate_key must be a string."),
+        ('encrypt_key', (str, NoneType), "Session encrypt_key must be a string."),
         ('encrypt_nonce_bits', (int, NoneType), "Session encrypt_nonce_bits must be a number"),
         ('secure', (bool, NoneType), "Session secure must be a boolean."),
         ('httponly', (bool, NoneType), "Session httponly must be a boolean."),