From 8eebd012b963a2f2783d54bb6e7363b451f38bc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?= <mpg@elzevir.fr>
Date: Fri, 9 Aug 2013 16:21:34 +0200
Subject: [PATCH] Add an ecdsa_genkey() function

---
 include/polarssl/ecdsa.h               | 14 ++++++++++++++
 library/ecdsa.c                        | 11 +++++++++++
 tests/suites/test_suite_ecdsa.function |  4 +---
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/include/polarssl/ecdsa.h b/include/polarssl/ecdsa.h
index 6dcb2838b..cd1987e31 100644
--- a/include/polarssl/ecdsa.h
+++ b/include/polarssl/ecdsa.h
@@ -125,6 +125,20 @@ int ecdsa_read_signature( ecdsa_context *ctx,
                           const unsigned char *hash, size_t hlen,
                           const unsigned char *sig, size_t slen );
 
+/**
+ * \brief           Generate an ECDSA keypair on the given curve
+ *
+ * \param ctx       ECDSA context in which the keypair should be stored
+ * \param grp       Group (elliptic curve) to use. One of the various
+ *                  POLARSSL_ECP_DP_XXX macros depending on configuration.
+ * \param f_rng     RNG function
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 on success, or a POLARSSL_ERR_ECP code.
+ */
+int ecdsa_genkey( ecdsa_context *ctx, ecp_group_id gid,
+                  int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
 /**
  * \brief           Initialize context
  *
diff --git a/library/ecdsa.c b/library/ecdsa.c
index cf5355c17..6746233b4 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -273,6 +273,17 @@ int ecdsa_read_signature( ecdsa_context *ctx,
     return( ecdsa_verify( &ctx->grp, hash, hlen, &ctx->Q, &ctx->r, &ctx->s ) );
 }
 
+/*
+ * Generate key pair
+ */
+int ecdsa_genkey( ecdsa_context *ctx, ecp_group_id gid,
+                  int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
+{
+    return( ecp_use_known_dp( &ctx->grp, gid ) ||
+            ecp_gen_keypair( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) );
+}
+
+
 /*
  * Initialize context
  */
diff --git a/tests/suites/test_suite_ecdsa.function b/tests/suites/test_suite_ecdsa.function
index 46dd1b3a5..b4d6ffdc6 100644
--- a/tests/suites/test_suite_ecdsa.function
+++ b/tests/suites/test_suite_ecdsa.function
@@ -95,9 +95,7 @@ void ecdsa_write_read_random( int id )
     TEST_ASSERT( rnd_pseudo_rand( &rnd_info, hash, sizeof( hash ) ) == 0 );
 
     /* generate signing key */
-    TEST_ASSERT( ecp_use_known_dp( &ctx.grp, id ) == 0 );
-    TEST_ASSERT( ecp_gen_keypair( &ctx.grp, &ctx.d, &ctx.Q,
-                                  &rnd_pseudo_rand, &rnd_info ) == 0 );
+    TEST_ASSERT( ecdsa_genkey( &ctx, id, &rnd_pseudo_rand, &rnd_info ) == 0 );
 
     /* generate and write signature, then read and verify it */
     TEST_ASSERT( ecdsa_write_signature( &ctx, hash, sizeof( hash ),