diff --git a/src/libstrongswan/plugins/serpent/serpent_crypter.c b/src/libstrongswan/plugins/serpent/serpent_crypter.c
index 4433a5485..9d53569ad 100644
--- a/src/libstrongswan/plugins/serpent/serpent_crypter.c
+++ b/src/libstrongswan/plugins/serpent/serpent_crypter.c
@@ -163,7 +163,7 @@ 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 = 24 || key_size == 32))
+	  !(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 e72f20700..a1c8659d7 100644
--- a/src/libstrongswan/plugins/twofish/twofish_crypter.c
+++ b/src/libstrongswan/plugins/twofish/twofish_crypter.c
@@ -163,7 +163,7 @@ 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 = 24 || key_size == 32))
+	  !(key_size == 16 || key_size == 24 || key_size == 32))
 	{
 		return NULL;
 	}