| /* |
| * Diffie-Hellman-Merkle key exchange (server side) |
| * |
| * Based on XySSL: Copyright (C) 2006-2008 Christophe Devine |
| * |
| * Copyright (C) 2009 Paul Bakker <polarssl_maintainer at polarssl dot org> |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * * Neither the names of PolarSSL or XySSL nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
| * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef _CRT_SECURE_NO_DEPRECATE |
| #define _CRT_SECURE_NO_DEPRECATE 1 |
| #endif |
| |
| #include <string.h> |
| #include <stdio.h> |
| |
| #include "polarssl/net.h" |
| #include "polarssl/aes.h" |
| #include "polarssl/dhm.h" |
| #include "polarssl/rsa.h" |
| #include "polarssl/sha1.h" |
| #include "polarssl/havege.h" |
| |
| #define SERVER_PORT 11999 |
| #define PLAINTEXT "==Hello there!==" |
| |
| int main( void ) |
| { |
| FILE *f; |
| |
| int ret, n, buflen; |
| int listen_fd = -1; |
| int client_fd = -1; |
| |
| unsigned char buf[1024]; |
| unsigned char hash[20]; |
| unsigned char buf2[2]; |
| |
| 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 ); |
| |
| /* |
| * 2a. Read the server's private RSA key |
| */ |
| printf( "\n . Reading private key from rsa_priv.txt" ); |
| fflush( stdout ); |
| |
| if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL ) |
| { |
| ret = 1; |
| printf( " failed\n ! Could not open rsa_priv.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 || |
| ( ret = mpi_read_file( &rsa.D , 16, f ) ) != 0 || |
| ( ret = mpi_read_file( &rsa.P , 16, f ) ) != 0 || |
| ( ret = mpi_read_file( &rsa.Q , 16, f ) ) != 0 || |
| ( ret = mpi_read_file( &rsa.DP, 16, f ) ) != 0 || |
| ( ret = mpi_read_file( &rsa.DQ, 16, f ) ) != 0 || |
| ( ret = mpi_read_file( &rsa.QP, 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 ); |
| |
| /* |
| * 2b. Get the DHM modulus and generator |
| */ |
| printf( "\n . Reading DH parameters from dh_prime.txt" ); |
| fflush( stdout ); |
| |
| if( ( f = fopen( "dh_prime.txt", "rb" ) ) == NULL ) |
| { |
| ret = 1; |
| printf( " failed\n ! Could not open dh_prime.txt\n" \ |
| " ! Please run dh_genprime first\n\n" ); |
| goto exit; |
| } |
| |
| if( mpi_read_file( &dhm.P, 16, f ) != 0 || |
| mpi_read_file( &dhm.G, 16, f ) != 0 ) |
| { |
| printf( " failed\n ! Invalid DH parameter file\n\n" ); |
| goto exit; |
| } |
| |
| fclose( f ); |
| |
| /* |
| * 3. Wait for a client to connect |
| */ |
| printf( "\n . Waiting for a remote connection" ); |
| fflush( stdout ); |
| |
| if( ( ret = net_bind( &listen_fd, NULL, SERVER_PORT ) ) != 0 ) |
| { |
| printf( " failed\n ! net_bind returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| if( ( ret = net_accept( listen_fd, &client_fd, NULL ) ) != 0 ) |
| { |
| printf( " failed\n ! net_accept returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| /* |
| * 4. Setup the DH parameters (P,G,Ys) |
| */ |
| printf( "\n . Sending the server's DH parameters" ); |
| fflush( stdout ); |
| |
| memset( buf, 0, sizeof( buf ) ); |
| |
| if( ( ret = dhm_make_params( &dhm, 256, buf, &n, |
| havege_rand, &hs ) ) != 0 ) |
| { |
| printf( " failed\n ! dhm_make_params returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| /* |
| * 5. Sign the parameters and send them |
| */ |
| sha1( buf, n, hash ); |
| |
| buf[n ] = (unsigned char)( rsa.len >> 8 ); |
| buf[n + 1] = (unsigned char)( rsa.len ); |
| |
| if( ( ret = rsa_pkcs1_sign( &rsa, RSA_PRIVATE, RSA_SHA1, |
| 0, hash, buf + n + 2 ) ) != 0 ) |
| { |
| printf( " failed\n ! rsa_pkcs1_sign returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| buflen = n + 2 + rsa.len; |
| buf2[0] = (unsigned char)( buflen >> 8 ); |
| buf2[1] = (unsigned char)( buflen ); |
| |
| if( ( ret = net_send( &client_fd, buf2, 2 ) ) != 2 || |
| ( ret = net_send( &client_fd, buf, buflen ) ) != buflen ) |
| { |
| printf( " failed\n ! net_send returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| /* |
| * 6. Get the client's public value: Yc = G ^ Xc mod P |
| */ |
| printf( "\n . Receiving the client's public value" ); |
| fflush( stdout ); |
| |
| memset( buf, 0, sizeof( buf ) ); |
| n = dhm.len; |
| |
| if( ( ret = net_recv( &client_fd, buf, n ) ) != n ) |
| { |
| printf( " failed\n ! net_recv returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| if( ( ret = dhm_read_public( &dhm, buf, dhm.len ) ) != 0 ) |
| { |
| printf( " failed\n ! dhm_read_public returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| /* |
| * 7. Derive the shared secret: K = Ys ^ Xc mod P |
| */ |
| printf( "\n . Shared secret: " ); |
| fflush( stdout ); |
| |
| 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 encryption 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 |
| * and MACs. |
| */ |
| printf( "...\n . Encrypting and sending the ciphertext" ); |
| fflush( stdout ); |
| |
| aes_setkey_enc( &aes, buf, 256 ); |
| memcpy( buf, PLAINTEXT, 16 ); |
| aes_crypt_ecb( &aes, AES_ENCRYPT, buf, buf ); |
| |
| if( ( ret = net_send( &client_fd, buf, 16 ) ) != 16 ) |
| { |
| printf( " failed\n ! net_send returned %d\n\n", ret ); |
| goto exit; |
| } |
| |
| printf( "\n\n" ); |
| |
| exit: |
| |
| net_close( client_fd ); |
| rsa_free( &rsa ); |
| dhm_free( &dhm ); |
| |
| #ifdef WIN32 |
| printf( " + Press Enter to exit this program.\n" ); |
| fflush( stdout ); getchar(); |
| #endif |
| |
| return( ret ); |
| } |