diff --git a/common/util.h b/common/util.h
index c6d19c64b..f3722812d 100644
--- a/common/util.h
+++ b/common/util.h
@@ -59,6 +59,11 @@
 /* Hash function used with libksba. */
 #define HASH_FNC ((void (*)(void *, const void*,size_t))gcry_md_write)
 
+/* The length of the keygrip.  This is a SHA-1 hash of the key
+ * parameters as generated by gcry_pk_get_keygrip.  */
+#define KEYGRIP_LEN 20
+
+
 /* Get all the stuff from jnlib. */
 #include "../common/logging.h"
 #include "../common/argparse.h"
diff --git a/g10/call-agent.c b/g10/call-agent.c
index 3874ac181..684771b75 100644
--- a/g10/call-agent.c
+++ b/g10/call-agent.c
@@ -1474,7 +1474,7 @@ agent_probe_any_secret_key (ctrl_t ctrl, kbnode_t keyblock)
   char *p;
   kbnode_t kbctx, node;
   int nkeys;
-  unsigned char grip[20];
+  unsigned char grip[KEYGRIP_LEN];
 
   err = start_agent (ctrl, 0);
   if (err)
diff --git a/g10/keyid.c b/g10/keyid.c
index c519bc581..de38580f2 100644
--- a/g10/keyid.c
+++ b/g10/keyid.c
@@ -959,18 +959,18 @@ gpg_error_t
 hexkeygrip_from_pk (PKT_public_key *pk, char **r_grip)
 {
   gpg_error_t err;
-  unsigned char grip[20];
+  unsigned char grip[KEYGRIP_LEN];
 
   *r_grip = NULL;
   err = keygrip_from_pk (pk, grip);
   if (!err)
     {
-      char * buf = xtrymalloc (20*2+1);
+      char * buf = xtrymalloc (KEYGRIP_LEN * 2 + 1);
       if (!buf)
         err = gpg_error_from_syserror ();
       else
         {
-          bin2hex (grip, 20, buf);
+          bin2hex (grip, KEYGRIP_LEN, buf);
           *r_grip = buf;
         }
     }