Index: usr.sbin/bhyve/Makefile
===================================================================
--- usr.sbin/bhyve/Makefile
+++ usr.sbin/bhyve/Makefile
@@ -61,7 +61,7 @@
 .PATH:  ${BHYVE_SYSDIR}/sys/amd64/vmm
 SRCS+=	vmm_instruction_emul.c
 
-LIBADD=	vmmapi md pthread z
+LIBADD=	vmmapi md pthread z crypto
 
 CFLAGS+= -I${BHYVE_SYSDIR}/sys/dev/e1000
 CFLAGS+= -I${BHYVE_SYSDIR}/sys/dev/mii
Index: usr.sbin/bhyve/bhyve.8
===================================================================
--- usr.sbin/bhyve/bhyve.8
+++ usr.sbin/bhyve/bhyve.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 3, 2017
+.Dd May 19, 2017
 .Dt BHYVE 8
 .Os
 .Sh NAME
@@ -309,7 +309,7 @@
 .Pp
 Framebuffer devices:
 .Bl -tag -width 10n
-.It Oo rfb= Ns Oo Ar IP: Oc Ns Ar port Oc Ns Oo ,w= Ns Ar width Oc Ns Oo ,h= Ns Ar height Oc Ns Oo ,vga= Ns Ar vgaconf Oc Ns Oo Ns ,wait Oc
+.It Oo rfb= Ns Oo Ar IP: Oc Ns Ar port Oc Ns Oo ,w= Ns Ar width Oc Ns Oo ,h= Ns Ar height Oc Ns Oo ,vga= Ns Ar vgaconf Oc Ns Oo Ns ,wait Oc Ns Oo ,password= Ns Ar password Oc
 .Bl -tag -width 8n
 .It Ar IP:port
 An
@@ -368,6 +368,9 @@
 to only boot upon the initiation of a VNC connection, simplifying the installation
 of operating systems that require immediate keyboard input.
 This can be removed for post-installation use.
+.It password
+The password implementation usage is only for interoperability with certain VNC
+clients and must not be used as a method to secure the VNC service.
 .El
 .El
 .Pp
Index: usr.sbin/bhyve/pci_fbuf.c
===================================================================
--- usr.sbin/bhyve/pci_fbuf.c
+++ usr.sbin/bhyve/pci_fbuf.c
@@ -93,6 +93,7 @@
 
 	/* rfb server */
 	char      *rfb_host;
+	char      *rfb_password;
 	int       rfb_port;
 	int       rfb_wait;
 	int       vga_enabled;
@@ -285,7 +286,8 @@
 				goto done;
 			} else if (sc->memregs.height == 0)
 				sc->memregs.height = 1080;
-
+		} else if (!strcmp(xopts, "password")) {
+			sc->rfb_password = config;
 		} else {
 			pci_fbuf_usage(xopts);
 			ret = -1;
@@ -407,7 +409,7 @@
 
 	memset((void *)sc->fb_base, 0, FB_SIZE);
 
-	error = rfb_init(sc->rfb_host, sc->rfb_port, sc->rfb_wait);
+	error = rfb_init(sc->rfb_host, sc->rfb_port, sc->rfb_wait, sc->rfb_password);
 done:
 	if (error)
 		free(sc);
Index: usr.sbin/bhyve/rfb.h
===================================================================
--- usr.sbin/bhyve/rfb.h
+++ usr.sbin/bhyve/rfb.h
@@ -31,6 +31,12 @@
 
 #define	RFB_PORT	5900
 
-int	rfb_init(char *hostname, int port, int wait);
+int	rfb_init(char *hostname, int port, int wait, char *password);
+
+#define SECURITY_TYPE_NONE 1
+#define SECURITY_TYPE_VNC_AUTH 2
+        
+#define AUTH_FAILED_UNAUTH 1
+#define AUTH_FAILED_ERROR 2
 
 #endif /* _RFB_H_ */
Index: usr.sbin/bhyve/rfb.c
===================================================================
--- usr.sbin/bhyve/rfb.c
+++ usr.sbin/bhyve/rfb.c
@@ -60,10 +60,14 @@
 #include "rfb.h"
 #include "sockstream.h"
 
+#include <openssl/des.h>
+
 static int rfb_debug = 0;
 #define	DPRINTF(params) if (rfb_debug) printf params
 #define	WPRINTF(params) printf params
 
+#define AUTH_LENGTH		16
+
 struct rfb_softc {
 	int		sfd;
 	pthread_t	tid;
@@ -72,10 +76,15 @@
 
 	int		width, height;
 
-	bool		enc_raw_ok;
-	bool		enc_zlib_ok;
-	bool		enc_resize_ok;
+	char		*password;
+	unsigned char	challenge[AUTH_LENGTH];
+	unsigned char	keystr[AUTH_LENGTH];
+	unsigned char	crypt_expected[AUTH_LENGTH];
 
+	bool	enc_raw_ok;
+	bool	enc_zlib_ok;
+	bool	enc_resize_ok;
+
 	z_stream	zstream;
 	uint8_t		*zbuf;
 	int		zbuflen;
@@ -739,9 +748,13 @@
 {
 	const char *vbuf = "RFB 003.008\n";
 	unsigned char buf[80];
+	unsigned char *message;
+
+	DES_key_schedule ks;
 	pthread_t tid;
-        uint32_t sres;
+	uint32_t sres;
 	int len;
+	int i;
 
 	rc->cfd = cfd;
 
@@ -753,17 +766,76 @@
 
 	/* 2a. Send security type 'none' */
 	buf[0] = 1;
-	buf[1] = 1; /* none */
+	if (rc->password) 
+		buf[1] = SECURITY_TYPE_VNC_AUTH;
+	else
+		buf[1] = SECURITY_TYPE_NONE;
+
 	stream_write(cfd, buf, 2);
 
-
 	/* 2b. Read agreed security type */
 	len = stream_read(cfd, buf, 1);
 
-	/* 2c. Write back a status of 0 */
-	sres = 0;
+	/* 2c. Do VNC authentication */
+	switch (buf[0]) {
+	case SECURITY_TYPE_NONE:
+		sres = 0;
+		break;
+	case SECURITY_TYPE_VNC_AUTH:
+		/*
+		 * The client encrypts the challenge with DES, using a password
+		 * supplied by the user as the key.  To form the key, the password
+		 * is truncated to eight characters, or padded with null bytes on
+		 * the right.  The client then sends the resulting 16-bytes response.
+		 */
+		strncpy(rc->keystr, rc->password, AUTH_LENGTH);
+
+		/* VNC clients encrypts the challenge with all the bit fields in each
+		 * byte of the password mirrored. Here we flip each byte of the keystr.
+		 */
+		for (i = 0; i < 16; i++) {
+			rc->keystr[i] = (rc->keystr[i] & 0xF0) >> 4
+				  | (rc->keystr[i] & 0x0F) << 4;
+			rc->keystr[i] = (rc->keystr[i] & 0xCC) >> 2
+				  | (rc->keystr[i] & 0x33) << 2;
+			rc->keystr[i] = (rc->keystr[i] & 0xAA) >> 1
+				  | (rc->keystr[i] & 0x55) << 1;
+		}
+
+		/* Initialize a 16-byte random challenge */
+		arc4random_buf(rc->challenge, sizeof(rc->challenge));
+		stream_write(cfd, rc->challenge, AUTH_LENGTH);
+
+		/* Receive the 16-byte challenge response */
+		stream_read(cfd, buf, AUTH_LENGTH);
+
+		/* We encrypt the challenge sent with the flipped keystr. */
+		DES_set_key((C_Block *)rc->keystr, &ks);
+		DES_ecb_encrypt((C_Block *)rc->challenge,
+		    (C_Block *)rc->crypt_expected, &ks, DES_ENCRYPT);
+		DES_ecb_encrypt((C_Block *)(rc->challenge + 8),
+		    (C_Block *)(rc->crypt_expected + 8), &ks, DES_ENCRYPT);
+
+		if (memcmp(buf, rc->crypt_expected, AUTH_LENGTH)) {
+			message = "Auth Failed: Invalid Password.";
+			sres = htonl(1);
+		}
+		else
+			sres = 0;
+
+		break;
+	}
+
+	/* 2d. Write back a status */
 	stream_write(cfd, &sres, 4);
 
+	if (sres) {
+		*((uint32_t *) buf) = htonl(strlen(message));
+		strncpy(buf + 4, message, strlen(message) + 1);
+		stream_write(cfd, buf, 4 + strlen(message));
+		goto done;
+	}
+
 	/* 3a. Read client shared-flag byte */
 	len = stream_read(cfd, buf, 1);
 
@@ -869,7 +941,7 @@
 }
 
 int
-rfb_init(char *hostname, int port, int wait)
+rfb_init(char *hostname, int port, int wait, char *password)
 {
 	struct rfb_softc *rc;
 	struct sockaddr_in sin;
@@ -886,6 +958,8 @@
 	                     sizeof(uint32_t));
 	rc->crc_width = RFB_MAX_WIDTH;
 	rc->crc_height = RFB_MAX_HEIGHT;
+
+	rc->password = password;
 
 	rc->sfd = socket(AF_INET, SOCK_STREAM, 0);
 	if (rc->sfd < 0) {