Diff: include/mbedtls/ecdh.h

Revision:

0:cdf462088d13

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/mbedtls/ecdh.h	Thu Jan 05 00:18:44 2017 +0000
@@ -0,0 +1,214 @@
+/**
+ * \file ecdh.h
+ *
+ * \brief Elliptic curve Diffie-Hellman
+ *
+ *  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)
+ */
+#ifndef MBEDTLS_ECDH_H
+#define MBEDTLS_ECDH_H
+
+#include "ecp.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * When importing from an EC key, select if it is our key or the peer's key
+ */
+typedef enum
+{
+    MBEDTLS_ECDH_OURS,
+    MBEDTLS_ECDH_THEIRS,
+} mbedtls_ecdh_side;
+
+/**
+ * \brief           ECDH context structure
+ */
+typedef struct
+{
+    mbedtls_ecp_group grp;      /*!<  elliptic curve used                           */
+    mbedtls_mpi d;              /*!<  our secret value (private key)                */
+    mbedtls_ecp_point Q;        /*!<  our public value (public key)                 */
+    mbedtls_ecp_point Qp;       /*!<  peer's public value (public key)              */
+    mbedtls_mpi z;              /*!<  shared secret                                 */
+    int point_format;   /*!<  format for point export in TLS messages       */
+    mbedtls_ecp_point Vi;       /*!<  blinding value (for later)                    */
+    mbedtls_ecp_point Vf;       /*!<  un-blinding value (for later)                 */
+    mbedtls_mpi _d;             /*!<  previous d (for later)                        */
+}
+mbedtls_ecdh_context;
+
+/**
+ * \brief           Generate a public key.
+ *                  Raw function that only does the core computation.
+ *
+ * \param grp       ECP group
+ * \param d         Destination MPI (secret exponent, aka private key)
+ * \param Q         Destination point (public key)
+ * \param f_rng     RNG function
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 if successful,
+ *                  or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
+ */
+int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
+                     int (*f_rng)(void *, unsigned char *, size_t),
+                     void *p_rng );
+
+/**
+ * \brief           Compute shared secret
+ *                  Raw function that only does the core computation.
+ *
+ * \param grp       ECP group
+ * \param z         Destination MPI (shared secret)
+ * \param Q         Public key from other party
+ * \param d         Our secret exponent (private key)
+ * \param f_rng     RNG function (see notes)
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 if successful,
+ *                  or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
+ *
+ * \note            If f_rng is not NULL, it is used to implement
+ *                  countermeasures against potential elaborate timing
+ *                  attacks, see \c mbedtls_ecp_mul() for details.
+ */
+int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
+                         const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
+                         int (*f_rng)(void *, unsigned char *, size_t),
+                         void *p_rng );
+
+/**
+ * \brief           Initialize context
+ *
+ * \param ctx       Context to initialize
+ */
+void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx );
+
+/**
+ * \brief           Free context
+ *
+ * \param ctx       Context to free
+ */
+void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx );
+
+/**
+ * \brief           Generate a public key and a TLS ServerKeyExchange payload.
+ *                  (First function used by a TLS server for ECDHE.)
+ *
+ * \param ctx       ECDH context
+ * \param olen      number of chars written
+ * \param buf       destination buffer
+ * \param blen      length of buffer
+ * \param f_rng     RNG function
+ * \param p_rng     RNG parameter
+ *
+ * \note            This function assumes that ctx->grp has already been
+ *                  properly set (for example using mbedtls_ecp_group_load).
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
+                      unsigned char *buf, size_t blen,
+                      int (*f_rng)(void *, unsigned char *, size_t),
+                      void *p_rng );
+
+/**
+ * \brief           Parse and procress a TLS ServerKeyExhange payload.
+ *                  (First function used by a TLS client for ECDHE.)
+ *
+ * \param ctx       ECDH context
+ * \param buf       pointer to start of input buffer
+ * \param end       one past end of buffer
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx,
+                      const unsigned char **buf, const unsigned char *end );
+
+/**
+ * \brief           Setup an ECDH context from an EC key.
+ *                  (Used by clients and servers in place of the
+ *                  ServerKeyEchange for static ECDH: import ECDH parameters
+ *                  from a certificate's EC key information.)
+ *
+ * \param ctx       ECDH constext to set
+ * \param key       EC key to use
+ * \param side      Is it our key (1) or the peer's key (0) ?
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx, const mbedtls_ecp_keypair *key,
+                     mbedtls_ecdh_side side );
+
+/**
+ * \brief           Generate a public key and a TLS ClientKeyExchange payload.
+ *                  (Second function used by a TLS client for ECDH(E).)
+ *
+ * \param ctx       ECDH context
+ * \param olen      number of bytes actually written
+ * \param buf       destination buffer
+ * \param blen      size of destination buffer
+ * \param f_rng     RNG function
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
+                      unsigned char *buf, size_t blen,
+                      int (*f_rng)(void *, unsigned char *, size_t),
+                      void *p_rng );
+
+/**
+ * \brief           Parse and process a TLS ClientKeyExchange payload.
+ *                  (Second function used by a TLS server for ECDH(E).)
+ *
+ * \param ctx       ECDH context
+ * \param buf       start of input buffer
+ * \param blen      length of input buffer
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx,
+                      const unsigned char *buf, size_t blen );
+
+/**
+ * \brief           Derive and export the shared secret.
+ *                  (Last function used by both TLS client en servers.)
+ *
+ * \param ctx       ECDH context
+ * \param olen      number of bytes written
+ * \param buf       destination buffer
+ * \param blen      buffer length
+ * \param f_rng     RNG function, see notes for \c mbedtls_ecdh_compute_shared()
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 if successful, or an MBEDTLS_ERR_ECP_XXX error code
+ */
+int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
+                      unsigned char *buf, size_t blen,
+                      int (*f_rng)(void *, unsigned char *, size_t),
+                      void *p_rng );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ecdh.h */