diff --git a/dss.h b/dss.h
index 0b69256..99a34ef 100644
--- a/dss.h
+++ b/dss.h
@@ -38,6 +38,7 @@ struct DSS_key {
 	mp_int* q;
 	mp_int* g;
 	mp_int* y;
+	/* x is the private part */
 	mp_int* x;
 
 };
diff --git a/rsa.h b/rsa.h
index 545ba9b..4b9f390 100644
--- a/rsa.h
+++ b/rsa.h
@@ -36,6 +36,7 @@ struct RSA_key {
 
 	mp_int* n;
 	mp_int* e;
+	/* d, p, and q are private parts */
 	mp_int* d;
 	mp_int* p;
 	mp_int* q;