diff --git a/src/libstrongswan/plugins/serpent/serpent_crypter.c b/src/libstrongswan/plugins/serpent/serpent_crypter.c
index d5256c6b9..4433a5485 100644
--- a/src/libstrongswan/plugins/serpent/serpent_crypter.c
+++ b/src/libstrongswan/plugins/serpent/serpent_crypter.c
@@ -162,7 +162,8 @@ serpent_crypter_t *serpent_crypter_create(encryption_algorithm_t algo, size_t ke
 {
 	private_serpent_crypter_t *this;
 	
-	if (algo != ENCR_SERPENT_CBC || !(key_size == 16 || key_size == 32))
+	if (algo != ENCR_SERPENT_CBC ||
+	  !(key_size == 16 || key_size = 24 || key_size == 32))
 	{
 		return NULL;
 	}
diff --git a/src/libstrongswan/plugins/twofish/twofish_crypter.c b/src/libstrongswan/plugins/twofish/twofish_crypter.c
index 63429932e..e72f20700 100644
--- a/src/libstrongswan/plugins/twofish/twofish_crypter.c
+++ b/src/libstrongswan/plugins/twofish/twofish_crypter.c
@@ -162,7 +162,8 @@ twofish_crypter_t *twofish_crypter_create(encryption_algorithm_t algo, size_t ke
 {
 	private_twofish_crypter_t *this;
 	
-	if (algo != ENCR_TWOFISH_CBC || !(key_size == 16 || key_size == 32))
+	if (algo != ENCR_TWOFISH_CBC ||
+	  !(key_size == 16 || key_size = 24 || key_size == 32))
 	{
 		return NULL;
 	}