diff --git a/ChangeLog b/ChangeLog
index 3ae2c1b..06c755c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2017-10-31  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* src/openpgp-do.c (gpg_do_keygen): Bug fix for memory alignment.
+
 2017-10-24  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* tests/card_reader.py (CardReader.ccid_power_on): Setting
diff --git a/src/openpgp-do.c b/src/openpgp-do.c
index bf77d9f..9acfba3 100644
--- a/src/openpgp-do.c
+++ b/src/openpgp-do.c
@@ -2067,10 +2067,10 @@ gpg_do_keygen (uint8_t *buf)
   const uint8_t *prv;
   const uint8_t *rnd;
   int r = 0;
-#define p_q buf
-#define d buf
-#define d1 (&buf[64])
-#define pubkey (&buf[256])
+#define p_q (&buf[3])
+#define d (&buf[3])
+#define d1 (&buf[3+64])
+#define pubkey (&buf[3+256])
 
   DEBUG_INFO ("Keygen\r\n");
   DEBUG_BYTE (kk_byte);