diff -up openssh-5.6p1/audit-bsm.c.audit2 openssh-5.6p1/audit-bsm.c
--- openssh-5.6p1/audit-bsm.c.audit2	2010-11-05 15:41:17.000000000 +0100
+++ openssh-5.6p1/audit-bsm.c	2010-11-05 15:45:28.000000000 +0100
@@ -316,6 +316,12 @@ audit_session_close(struct logininfo *li
 	/* not implemented */
 }
 
+int
+audit_keyusage(int host_user, const char *type, unsigned len, char *fp, int rv)
+{
+	/* not implemented */
+}
+
 void
 audit_event(ssh_audit_event_t event)
 {
diff -up openssh-5.6p1/audit.c.audit2 openssh-5.6p1/audit.c
--- openssh-5.6p1/audit.c.audit2	2010-11-05 15:41:17.000000000 +0100
+++ openssh-5.6p1/audit.c	2010-11-05 15:51:37.000000000 +0100
@@ -111,6 +111,33 @@ audit_event_lookup(ssh_audit_event_t ev)
 	return(event_lookup[i].name);
 }
 
+int
+audit_key(int type, int *rv, const Key *key)
+{
+	char *fp;
+	unsigned size = 0;
+	const char *crypto_name[] = {
+		"ssh-rsa1",
+		"ssh-rsa",
+		"ssh-dsa",
+		"unknown" };
+
+	fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
+	switch(key->type) {
+		case KEY_RSA1:
+		case KEY_RSA:
+			size = RSA_size(key->rsa);
+			break;
+		case KEY_DSA:
+			size = DSA_size(key->dsa);
+			break;
+	}
+
+	if (audit_keyusage(0, crypto_name[key->type], size, fp, *rv) == 0)
+		*rv = 0;
+	xfree(fp);
+}
+
 # ifndef CUSTOM_SSH_AUDIT_EVENTS
 /*
  * Null implementations of audit functions.
@@ -182,5 +209,17 @@ audit_run_command(const char *command)
 	debug("audit run command euid %d user %s command '%.200s'", geteuid(),
 	    audit_username(), command);
 }
+
+/*
+ * This will be called when user is successfully autherized by the RSA1/RSA/DSA key.
+ *
+ * Type is the key type, len is the key length(byte) and fp is the fingerprint of the key.
+ */
+int
+audit_keyusage(int host_user, const char *type, unsigned len, char *fp, int rv)
+{
+	debug("audit %s key usage euid %d user %s key type %s key length %d fingerprint %s, result %d", 
+		host_user ? "hostbased" : "pubkey", geteuid(), audit_username(), type, len, fp, rv);
+}
 # endif  /* !defined CUSTOM_SSH_AUDIT_EVENTS */
 #endif /* SSH_AUDIT_EVENTS */
diff -up openssh-5.6p1/audit.h.audit2 openssh-5.6p1/audit.h
--- openssh-5.6p1/audit.h.audit2	2010-11-05 15:41:17.000000000 +0100
+++ openssh-5.6p1/audit.h	2010-11-05 15:41:18.000000000 +0100
@@ -28,6 +28,7 @@
 # define _SSH_AUDIT_H
 
 #include "loginrec.h"
+#include "key.h"
 
 enum ssh_audit_event_type {
 	SSH_LOGIN_EXCEED_MAXTRIES,
@@ -53,5 +54,7 @@ void	audit_session_open(struct logininfo
 void	audit_session_close(struct logininfo *);
 void	audit_run_command(const char *);
 ssh_audit_event_t audit_classify_auth(const char *);
+int	audit_keyusage(int, const char *, unsigned, char *, int);
+int	audit_key(int, int *, const Key *);
 
 #endif /* _SSH_AUDIT_H */
diff -up openssh-5.6p1/audit-linux.c.audit2 openssh-5.6p1/audit-linux.c
--- openssh-5.6p1/audit-linux.c.audit2	2010-11-05 15:41:17.000000000 +0100
+++ openssh-5.6p1/audit-linux.c	2010-11-05 15:41:18.000000000 +0100
@@ -37,6 +37,8 @@
 #include "audit.h"
 #include "canohost.h"
 
+#define AUDIT_LOG_SIZE 128
+
 const char* audit_username(void);
 
 int
@@ -62,6 +64,36 @@ linux_audit_record_event(int uid, const 
 	return (rc >= 0);
 }
 
+int
+audit_keyusage(int host_user, const char *type, unsigned len, char *fp, int rv)
+{
+	char buf[AUDIT_LOG_SIZE];
+	int audit_fd, rc, saved_errno;
+
+	audit_fd = audit_open();
+	if (audit_fd < 0) {
+		if (errno == EINVAL || errno == EPROTONOSUPPORT ||
+					 errno == EAFNOSUPPORT)
+			return 1; /* No audit support in kernel */
+		else                                                                                                                                       
+			return 0; /* Must prevent login */
+	}
+	snprintf(buf, sizeof(buf), "%s_auth rport=%d", host_user ? "hostbased" : "pubkey", get_remote_port());
+	rc = audit_log_acct_message(audit_fd, AUDIT_USER_AUTH, NULL,
+		buf, audit_username(), -1, NULL, get_remote_ipaddr(), NULL, rv);
+	if (rc < 0)
+		goto out;
+	snprintf(buf, sizeof(buf), "key algo=%s size=%d fp=%s rport=%d",
+			type, 8 * len, fp, get_remote_port());
+	rc = audit_log_acct_message(audit_fd, AUDIT_USER_AUTH, NULL,
+		buf, audit_username(), -1, NULL, get_remote_ipaddr(), NULL, rv);
+out:
+	saved_errno = errno;
+	audit_close(audit_fd);
+	errno = saved_errno;
+	return (rc >= 0);
+}
+
 /* Below is the sshd audit API code */
 
 void
diff -up openssh-5.6p1/auth2-hostbased.c.audit2 openssh-5.6p1/auth2-hostbased.c
--- openssh-5.6p1/auth2-hostbased.c.audit2	2010-08-05 05:04:50.000000000 +0200
+++ openssh-5.6p1/auth2-hostbased.c	2010-11-05 15:41:18.000000000 +0100
@@ -136,6 +136,18 @@ done:
 	return authenticated;
 }
 
+int
+hostkey_key_verify(const Key *key, const u_char *sig, u_int slen, const u_char *data, u_int datalen)
+{
+	int rv;
+
+	rv = key_verify(key, sig, slen, data, datalen);
+#ifdef SSH_AUDIT_EVENTS
+	audit_key(0, &rv, key);
+#endif
+	return rv;
+}
+
 /* return 1 if given hostkey is allowed */
 int
 hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
diff -up openssh-5.6p1/auth2-pubkey.c.audit2 openssh-5.6p1/auth2-pubkey.c
--- openssh-5.6p1/auth2-pubkey.c.audit2	2010-07-02 05:35:19.000000000 +0200
+++ openssh-5.6p1/auth2-pubkey.c	2010-11-05 15:41:18.000000000 +0100
@@ -177,6 +177,18 @@ done:
 	return authenticated;
 }
 
+int
+pubkey_key_verify(const Key *key, const u_char *sig, u_int slen, const u_char *data, u_int datalen)
+{
+	int rv;
+
+	rv = key_verify(key, sig, slen, data, datalen);
+#ifdef SSH_AUDIT_EVENTS
+	audit_key(1, &rv, key);
+#endif
+	return rv;
+}
+
 static int
 match_principals_option(const char *principal_list, struct KeyCert *cert)
 {
diff -up openssh-5.6p1/auth.h.audit2 openssh-5.6p1/auth.h
--- openssh-5.6p1/auth.h.audit2	2010-05-10 03:58:03.000000000 +0200
+++ openssh-5.6p1/auth.h	2010-11-05 15:41:18.000000000 +0100
@@ -170,6 +170,7 @@ void	abandon_challenge_response(Authctxt
 char	*authorized_keys_file(struct passwd *);
 char	*authorized_keys_file2(struct passwd *);
 char	*authorized_principals_file(struct passwd *);
+int	 pubkey_key_verify(const Key *, const u_char *, u_int, const u_char *, u_int);
 
 FILE	*auth_openkeyfile(const char *, struct passwd *, int);
 FILE	*auth_openprincipals(const char *, struct passwd *, int);
@@ -185,6 +186,7 @@ Key	*get_hostkey_public_by_type(int);
 Key	*get_hostkey_private_by_type(int);
 int	 get_hostkey_index(Key *);
 int	 ssh1_session_key(BIGNUM *);
+int	 hostkey_key_verify(const Key *, const u_char *, u_int, const u_char *, u_int);
 
 /* debug messages during authentication */
 void	 auth_debug_add(const char *fmt,...) __attribute__((format(printf, 1, 2)));
diff -up openssh-5.6p1/auth-rsa.c.audit2 openssh-5.6p1/auth-rsa.c
--- openssh-5.6p1/auth-rsa.c.audit2	2010-07-16 05:58:37.000000000 +0200
+++ openssh-5.6p1/auth-rsa.c	2010-11-05 15:41:18.000000000 +0100
@@ -92,7 +92,10 @@ auth_rsa_verify_response(Key *key, BIGNU
 {
 	u_char buf[32], mdbuf[16];
 	MD5_CTX md;
-	int len;
+	int len, rv;
+#ifdef SSH_AUDIT_EVENTS
+	char *fp;
+#endif
 
 	if (auth_key_is_revoked(key))
 		return 0;
@@ -116,12 +119,18 @@ auth_rsa_verify_response(Key *key, BIGNU
 	MD5_Final(mdbuf, &md);
 
 	/* Verify that the response is the original challenge. */
-	if (timingsafe_bcmp(response, mdbuf, 16) != 0) {
-		/* Wrong answer. */
-		return (0);
+	rv = timingsafe_bcmp(response, mdbuf, 16) == 0;
+
+#ifdef SSH_AUDIT_EVENTS
+	fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
+	if (audit_keyusage(1, "ssh-rsa1", RSA_size(key->rsa), fp, rv) == 0) {
+		debug("unsuccessful audit");
+		rv = 0;
 	}
-	/* Correct answer. */
-	return (1);
+	xfree(fp);
+#endif
+
+	return rv;
 }
 
 /*
diff -up openssh-5.6p1/monitor.c.audit2 openssh-5.6p1/monitor.c
--- openssh-5.6p1/monitor.c.audit2	2010-08-03 07:50:16.000000000 +0200
+++ openssh-5.6p1/monitor.c	2010-11-05 15:41:18.000000000 +0100
@@ -1235,7 +1235,19 @@ mm_answer_keyverify(int sock, Buffer *m)
 	if (!valid_data)
 		fatal("%s: bad signature data blob", __func__);
 
-	verified = key_verify(key, signature, signaturelen, data, datalen);
+	switch (key_blobtype) {
+	case MM_USERKEY:
+		verified = pubkey_key_verify(key, signature, signaturelen, data, datalen);
+		break;
+	case MM_HOSTKEY:
+		verified = hostkey_key_verify(key, signature, signaturelen, data, datalen);
+		valid_data = monitor_valid_hostbasedblob(data, datalen,
+		    hostbased_cuser, hostbased_chost);
+		break;
+	default:
+		verified = 0;
+		break;
+	}
 	debug3("%s: key %p signature %s",
 	    __func__, key, (verified == 1) ? "verified" : "unverified");