diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
new file mode 100644
index 0000000..2122078
--- /dev/null
+++ b/programs/pkey/dh_client.c
@@ -0,0 +1,249 @@
+/*
+ *  Diffie-Hellman-Merkle key exchange (client side)
+ *
+ *  Copyright (C) 2006-2007  Christophe Devine
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _CRT_SECURE_NO_DEPRECATE
+#define _CRT_SECURE_NO_DEPRECATE 1
+#endif
+
+#include <string.h>
+#include <stdio.h>
+
+#include "xyssl/net.h"
+#include "xyssl/aes.h"
+#include "xyssl/dhm.h"
+#include "xyssl/rsa.h"
+#include "xyssl/sha1.h"
+#include "xyssl/havege.h"
+
+#define SERVER_NAME "localhost"
+#define SERVER_PORT 11999
+
+int main( void )
+{
+    FILE *f;
+
+    int ret, n, buflen;
+    int server_fd = -1;
+
+    unsigned char *p, *end;
+    unsigned char buf[1024];
+    unsigned char hash[20];
+
+    havege_state hs;
+    rsa_context rsa;
+    dhm_context dhm;
+    aes_context aes;
+
+    memset( &rsa, 0, sizeof( rsa ) );
+    memset( &dhm, 0, sizeof( dhm ) );
+
+    /*
+     * 1. Setup the RNG
+     */
+    printf( "\n  . Seeding the random number generator" );
+    fflush( stdout );
+
+    havege_init( &hs );
+
+    /*
+     * 2. Read the server's public RSA key
+     */
+    printf( "\n  . Reading public key from rsa_pub.txt" );
+    fflush( stdout );
+
+    if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
+    {
+        ret = 1;
+        printf( " failed\n  ! Could not open rsa_pub.txt\n" \
+                "  ! Please run rsa_genkey first\n\n" );
+        goto exit;
+    }
+
+    rsa_init( &rsa, RSA_PKCS_V15, 0, NULL, NULL );
+
+    if( ( ret = mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
+        ( ret = mpi_read_file( &rsa.E, 16, f ) ) != 0 )
+    {
+        printf( " failed\n  ! mpi_read_file returned %d\n\n", ret );
+        goto exit;
+    }
+
+    rsa.len = ( mpi_msb( &rsa.N ) + 7 ) >> 3;
+
+    fclose( f );
+
+    /*
+     * 3. Initiate the connection
+     */
+    printf( "\n  . Connecting to tcp/%s/%d", SERVER_NAME,
+                                             SERVER_PORT );
+    fflush( stdout );
+
+    if( ( ret = net_connect( &server_fd, SERVER_NAME,
+                                         SERVER_PORT ) ) != 0 )
+    {
+        printf( " failed\n  ! net_connect returned %d\n\n", ret );
+        goto exit;
+    }
+
+    /*
+     * 4a. First get the buffer length
+     */
+    printf( "\n  . Receiving the server's DH parameters" );
+    fflush( stdout );
+
+    memset( buf, 0, sizeof( buf ) );
+
+    if( ( ret = net_recv( &server_fd, buf, 2 ) ) != 2 )
+    {
+        printf( " failed\n  ! net_recv returned %d\n\n", ret );
+        goto exit;
+    }
+
+    n = buflen = ( buf[0] << 8 ) | buf[1];
+    if( buflen < 1 || buflen > (int) sizeof( buf ) )
+    {
+        printf( " failed\n  ! Got an invalid buffer length\n\n" );
+        goto exit;
+    }
+
+    /*
+     * 4b. Get the DHM parameters: P, G and Ys = G^Xs mod P
+     */
+    memset( buf, 0, sizeof( buf ) );
+
+    if( ( ret = net_recv( &server_fd, buf, n ) ) != n )
+    {
+        printf( " failed\n  ! net_recv returned %d\n\n", ret );
+        goto exit;
+    }
+
+    p = buf, end = buf + buflen;
+
+    if( ( ret = dhm_read_params( &dhm, &p, end ) ) != 0 )
+    {
+        printf( " failed\n  ! dhm_read_params returned %d\n\n", ret );
+        goto exit;
+    }
+
+    if( dhm.len < 64 || dhm.len > 256 )
+    {
+        ret = 1;
+        printf( " failed\n  ! Invalid DHM modulus size\n\n" );
+        goto exit;
+    }
+
+    /*
+     * 5. Check that the server's RSA signature matches
+     *    the SHA-1 hash of (P,G,Ys)
+     */
+    printf( "\n  . Verifying the server's RSA signature" );
+    fflush( stdout );
+
+    if( ( n = (int)( end - p ) ) != rsa.len )
+    {
+        ret = 1;
+        printf( " failed\n  ! Invalid RSA signature size\n\n" );
+        goto exit;
+    }
+
+    sha1( buf, (int)( p - 2 - buf ), hash );
+
+    if( ( ret = rsa_pkcs1_verify( &rsa, RSA_PUBLIC, RSA_SHA1,
+                                  0, hash, p ) ) != 0 )
+    {
+        printf( " failed\n  ! rsa_pkcs1_verify returned %d\n\n", ret );
+        goto exit;
+    }
+
+    /*
+     * 6. Send our public value: Yc = G ^ Xc mod P
+     */
+    printf( "\n  . Sending own public value to server" );
+    fflush( stdout );
+
+    n = dhm.len;
+    if( ( ret = dhm_make_public( &dhm, 256, buf, n,
+                                 havege_rand, &hs ) ) != 0 )
+    {
+        printf( " failed\n  ! dhm_make_public returned %d\n\n", ret );
+        goto exit;
+    }
+
+    if( ( ret = net_send( &server_fd, buf, n ) ) != n )
+    {
+        printf( " failed\n  ! net_send returned %d\n\n", ret );
+        goto exit;
+    }
+
+    /*
+     * 7. Derive the shared secret: K = Ys ^ Xc mod P
+     */
+    printf( "\n  . Shared secret: " );
+    fflush( stdout );
+
+    n = dhm.len;
+    if( ( ret = dhm_calc_secret( &dhm, buf, &n ) ) != 0 )
+    {
+        printf( " failed\n  ! dhm_calc_secret returned %d\n\n", ret );
+        goto exit;
+    }
+
+    for( n = 0; n < 16; n++ )
+        printf( "%02x", buf[n] );
+
+    /*
+     * 8. Setup the AES-256 decryption key
+     *
+     * This is an overly simplified example; best practice is
+     * to hash the shared secret with a random value to derive
+     * the keying material for the encryption/decryption keys,
+     * IVs and MACs.
+     */
+    printf( "...\n  . Receiving and decrypting the ciphertext" );
+    fflush( stdout );
+
+    aes_setkey_dec( &aes, buf, 256 );
+
+    memset( buf, 0, sizeof( buf ) );
+
+    if( ( ret = net_recv( &server_fd, buf, 16 ) ) != 16 )
+    {
+        printf( " failed\n  ! net_recv returned %d\n\n", ret );
+        goto exit;
+    }
+
+    aes_crypt_ecb( &aes, AES_DECRYPT, buf, buf );
+    buf[16] = '\0';
+    printf( "\n  . Plaintext is \"%s\"\n\n", (char *) buf );
+
+exit:
+
+    net_close( server_fd );
+    rsa_free( &rsa );
+    dhm_free( &dhm );
+
+#ifdef WIN32
+    printf( "  + Press Enter to exit this program.\n" );
+    fflush( stdout ); getchar();
+#endif
+
+    return( ret );
+}