Add example program for Curve25519
Getting a lot of questions about how to use it. This will hopefully get people
started.
diff --git a/programs/Makefile b/programs/Makefile
index 544a2d8..443689b 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -49,6 +49,7 @@
hash/hello$(EXEXT) hash/generic_sum$(EXEXT) \
pkey/dh_client$(EXEXT) \
pkey/dh_genprime$(EXEXT) pkey/dh_server$(EXEXT) \
+ pkey/ecdh_curve25519$(EXEXT) \
pkey/ecdsa$(EXEXT) pkey/gen_key$(EXEXT) \
pkey/key_app$(EXEXT) pkey/key_app_writer$(EXEXT) \
pkey/mpi_demo$(EXEXT) pkey/pk_decrypt$(EXEXT) \
@@ -112,6 +113,10 @@
echo " CC pkey/dh_server.c"
$(CC) $(LOCAL_CFLAGS) $(CFLAGS) pkey/dh_server.c $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
+pkey/ecdh_curve25519$(EXEXT): pkey/ecdh_curve25519.c $(DEP)
+ echo " CC pkey/ecdh_curve25519.c"
+ $(CC) $(LOCAL_CFLAGS) $(CFLAGS) pkey/ecdh_curve25519.c $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
+
pkey/ecdsa$(EXEXT): pkey/ecdsa.c $(DEP)
echo " CC pkey/ecdsa.c"
$(CC) $(LOCAL_CFLAGS) $(CFLAGS) pkey/ecdsa.c $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
diff --git a/programs/pkey/CMakeLists.txt b/programs/pkey/CMakeLists.txt
index 8dc7def..5a37a42 100644
--- a/programs/pkey/CMakeLists.txt
+++ b/programs/pkey/CMakeLists.txt
@@ -7,6 +7,9 @@
add_executable(dh_server dh_server.c)
target_link_libraries(dh_server mbedtls)
+add_executable(ecdh_curve25519 ecdh_curve25519.c)
+target_link_libraries(ecdh_curve25519 mbedtls)
+
add_executable(ecdsa ecdsa.c)
target_link_libraries(ecdsa mbedtls)
diff --git a/programs/pkey/ecdh_curve25519.c b/programs/pkey/ecdh_curve25519.c
new file mode 100644
index 0000000..aa15c46
--- /dev/null
+++ b/programs/pkey/ecdh_curve25519.c
@@ -0,0 +1,237 @@
+/*
+ * Example ECDHE with Curve25519 program
+ *
+ * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdio.h>
+#define mbedtls_printf printf
+#endif
+
+#if !defined(MBEDTLS_ECDH_C) || \
+ !defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
+ !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C)
+int main( void )
+{
+ mbedtls_printf( "MBEDTLS_ECDH_C and/or "
+ "MBEDTLS_ECP_DP_CURVE25519_ENABLED and/or "
+ "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C "
+ "not defined\n" );
+ return( 0 );
+}
+#else
+
+#include "mbedtls/entropy.h"
+#include "mbedtls/ctr_drbg.h"
+#include "mbedtls/ecdh.h"
+
+int main( int argc, char *argv[] )
+{
+ int ret;
+ mbedtls_ecdh_context ctx_cli, ctx_srv;
+ mbedtls_entropy_context entropy;
+ mbedtls_ctr_drbg_context ctr_drbg;
+ unsigned char cli_to_srv[32], srv_to_cli[32];
+ const char pers[] = "ecdh";
+ ((void) argc);
+ ((void) argv);
+
+ mbedtls_ecdh_init( &ctx_cli );
+ mbedtls_ecdh_init( &ctx_srv );
+ mbedtls_ctr_drbg_init( &ctr_drbg );
+
+ /*
+ * Initialize random number generation
+ */
+ mbedtls_printf( " . Seeding the random number generator..." );
+ fflush( stdout );
+
+ mbedtls_entropy_init( &entropy );
+ if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
+ (const unsigned char *) pers,
+ sizeof pers ) ) != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+ /*
+ * Client: inialize context and generate keypair
+ */
+ mbedtls_printf( " . Setting up client context..." );
+ fflush( stdout );
+
+ ret = mbedtls_ecp_group_load( &ctx_cli.grp, MBEDTLS_ECP_DP_CURVE25519 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_ecdh_gen_public( &ctx_cli.grp, &ctx_cli.d, &ctx_cli.Q,
+ mbedtls_ctr_drbg_random, &ctr_drbg );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_mpi_write_binary( &ctx_cli.Q.X, cli_to_srv, 32 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+ /*
+ * Server: initialize context and generate keypair
+ */
+ mbedtls_printf( " . Setting up server context..." );
+ fflush( stdout );
+
+ ret = mbedtls_ecp_group_load( &ctx_srv.grp, MBEDTLS_ECP_DP_CURVE25519 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_ecdh_gen_public( &ctx_srv.grp, &ctx_srv.d, &ctx_srv.Q,
+ mbedtls_ctr_drbg_random, &ctr_drbg );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_mpi_write_binary( &ctx_srv.Q.X, srv_to_cli, 32 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+ /*
+ * Server: read peer's key and generate shared secret
+ */
+ mbedtls_printf( " . Server reading client key and computing secret..." );
+ fflush( stdout );
+
+ ret = mbedtls_mpi_lset( &ctx_srv.Qp.Z, 1 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_mpi_read_binary( &ctx_srv.Qp.X, cli_to_srv, 32 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_ecdh_compute_shared( &ctx_srv.grp, &ctx_srv.z,
+ &ctx_srv.Qp, &ctx_srv.d,
+ mbedtls_ctr_drbg_random, &ctr_drbg );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+ /*
+ * Client: read peer's key and generate shared secret
+ */
+ mbedtls_printf( " . Client reading server key and computing secret..." );
+ fflush( stdout );
+
+ ret = mbedtls_mpi_lset( &ctx_cli.Qp.Z, 1 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_mpi_read_binary( &ctx_cli.Qp.X, srv_to_cli, 32 );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
+ goto exit;
+ }
+
+ ret = mbedtls_ecdh_compute_shared( &ctx_cli.grp, &ctx_cli.z,
+ &ctx_cli.Qp, &ctx_cli.d,
+ mbedtls_ctr_drbg_random, &ctr_drbg );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+ /*
+ * Verification: are the computed secret equal?
+ */
+ mbedtls_printf( " . Checking if both computed secrets are equal..." );
+ fflush( stdout );
+
+ ret = mbedtls_mpi_cmp_mpi( &ctx_cli.z, &ctx_srv.z );
+ if( ret != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
+ goto exit;
+ }
+
+ mbedtls_printf( " ok\n" );
+
+
+exit:
+
+#if defined(_WIN32)
+ mbedtls_printf( " + Press Enter to exit this program.\n" );
+ fflush( stdout ); getchar();
+#endif
+
+ mbedtls_ecdh_free( &ctx_srv );
+ mbedtls_ecdh_free( &ctx_cli );
+ mbedtls_ctr_drbg_free( &ctr_drbg );
+ mbedtls_entropy_free( &entropy );
+
+ return( ret != 0 );
+}
+#endif /* MBEDTLS_ECDH_C && MBEDTLS_ECP_DP_CURVE25519_ENABLED &&
+ MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */