diff --git a/src/libstrongswan/plugins/pem/pem_encoder.c b/src/libstrongswan/plugins/pem/pem_encoder.c
index e255d6fd0..9c8237e4d 100644
--- a/src/libstrongswan/plugins/pem/pem_encoder.c
+++ b/src/libstrongswan/plugins/pem/pem_encoder.c
@@ -111,7 +111,7 @@ bool pem_encoder_encode(cred_encoding_type_t type, chunk_t *encoding,
 	}
 
 	/* compute and allocate maximum size of PEM object */
-	pem_chars = 4*(asn1.len + 2)/3;
+	pem_chars = 4 * ((asn1.len + 2) / 3);
 	pem_lines = (asn1.len + BYTES_PER_LINE - 1) / BYTES_PER_LINE;
 	*encoding = chunk_alloc(5 + 2*(6 + strlen(label) + 6) + 3 + pem_chars + pem_lines);
 	pos = encoding->ptr;