text: /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project 2006.
   */
  /* ====================================================================
   * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. 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.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED 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 OpenSSL PROJECT OR
   * ITS 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.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  
  #include <stdio.h>
  #include "cryptlib.h"
  #include <openssl/asn1t.h>
  #include <openssl/x509.h>
  #include <openssl/ec.h>
  #include <openssl/ecdsa.h>
  #include <openssl/evp.h>
  #include "evp_locl.h"
  
  /* EC pkey context structure */
  
  typedef struct
  	{
  	/* Key and paramgen group */
  	EC_GROUP *gen_group;
  	/* message digest */
  	const EVP_MD *md;
  	} EC_PKEY_CTX;
  
  static int pkey_ec_init(EVP_PKEY_CTX *ctx)
  	{
  	EC_PKEY_CTX *dctx;
  	dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
  	if (!dctx)
  		return 0;
  	dctx->gen_group = NULL;
  	dctx->md = NULL;
  
  	ctx->data = dctx;
  
  	return 1;
  	}
  
  static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
  	{
  	EC_PKEY_CTX *dctx, *sctx;
  	if (!pkey_ec_init(dst))
  		return 0;
         	sctx = src->data;
  	dctx = dst->data;
  	if (sctx->gen_group)
  		{
  		dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
  		if (!dctx->gen_group)
  			return 0;
  		}
  	dctx->md = sctx->md;
  	return 1;
  	}
  
  static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
  	{
  	EC_PKEY_CTX *dctx = ctx->data;
  	if (dctx)
  		{
  		if (dctx->gen_group)
  			EC_GROUP_free(dctx->gen_group);
  		OPENSSL_free(dctx);
  		}
  	}
  
  static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
  					const unsigned char *tbs, size_t tbslen)
  	{
  	int ret, type;
  	unsigned int sltmp;
  	EC_PKEY_CTX *dctx = ctx->data;
  	EC_KEY *ec = ctx->pkey->pkey.ec;
  
  	if (!sig)
  		{
  		*siglen = ECDSA_size(ec);
  		return 1;
  		}
  	else if(*siglen < (size_t)ECDSA_size(ec))
  		{
  		ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
  		return 0;
  		}
  
  	if (dctx->md)
  		type = EVP_MD_type(dctx->md);
  	else
  		type = NID_sha1;
  
  
  	ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
  
  	if (ret <= 0)
  		return ret;
  	*siglen = (size_t)sltmp;
  	return 1;
  	}
  
  static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
  					const unsigned char *sig, size_t siglen,
  					const unsigned char *tbs, size_t tbslen)
  	{
  	int ret, type;
  	EC_PKEY_CTX *dctx = ctx->data;
  	EC_KEY *ec = ctx->pkey->pkey.ec;
  
  	if (dctx->md)
  		type = EVP_MD_type(dctx->md);
  	else
  		type = NID_sha1;
  
  	ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
  
  	return ret;
  	}
  
  static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
  	{
  	int ret;
  	size_t outlen;
  	const EC_POINT *pubkey = NULL;
  	if (!ctx->pkey || !ctx->peerkey)
  		{
  		ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
  		return 0;
  		}
  
  	if (!key)
  		{
  		const EC_GROUP *group;
  		group = EC_KEY_get0_group(ctx->pkey->pkey.ec);
  		*keylen = (EC_GROUP_get_degree(group) + 7)/8;
  		return 1;
  		}
  
  	pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
  
  	/* NB: unlike PKS#3 DH, if *outlen is less than maximum size this is
  	 * not an error, the result is truncated.
  	 */
  
  	outlen = *keylen;
  		
  	ret = ECDH_compute_key(key, outlen, pubkey, ctx->pkey->pkey.ec, 0);
  	if (ret < 0)
  		return ret;
  	*keylen = ret;
  	return 1;
  	}
  
  static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
  	{
  	EC_PKEY_CTX *dctx = ctx->data;
  	EC_GROUP *group;
  	switch (type)
  		{
  		case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
  		group = EC_GROUP_new_by_curve_name(p1);
  		if (group == NULL)
  			{
  			ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
  			return 0;
  			}
  		if (dctx->gen_group)
  			EC_GROUP_free(dctx->gen_group);
  		dctx->gen_group = group;
  		return 1;
  
  		case EVP_PKEY_CTRL_MD:
  		if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
  		    EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
  		    EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
  		    EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
  		    EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
  		    EVP_MD_type((const EVP_MD *)p2) != NID_sha512)
  			{
  			ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
  			return 0;
  			}
  		dctx->md = p2;
  		return 1;
  
  		case EVP_PKEY_CTRL_PEER_KEY:
  		/* Default behaviour is OK */
  		case EVP_PKEY_CTRL_DIGESTINIT:
  		case EVP_PKEY_CTRL_PKCS7_SIGN:
  		case EVP_PKEY_CTRL_CMS_SIGN:
  		return 1;
  
  		default:
  		return -2;
  
  		}
  	}
  			
  static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
  			const char *type, const char *value)
  	{
  	if (!strcmp(type, "ec_paramgen_curve"))
  		{
  		int nid;
  		nid = OBJ_sn2nid(value);
  		if (nid == NID_undef)
  			nid = OBJ_ln2nid(value);
  		if (nid == NID_undef)
  			{
  			ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
  			return 0;
  			}
  		return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
  		}
  	return -2;
  	}
  
  static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
  	{
  	EC_KEY *ec = NULL;
  	EC_PKEY_CTX *dctx = ctx->data;
  	int ret = 0;
  	if (dctx->gen_group == NULL)
  		{
  		ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
  		return 0;
  		}
  	ec = EC_KEY_new();
  	if (!ec)
  		return 0;
  	ret = EC_KEY_set_group(ec, dctx->gen_group);
  	if (ret)
  		EVP_PKEY_assign_EC_KEY(pkey, ec);
  	else
  		EC_KEY_free(ec);
  	return ret;
  	}
  
  static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
  	{
  	EC_KEY *ec = NULL;
  	if (ctx->pkey == NULL)
  		{
  		ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
  		return 0;
  		}
  	ec = EC_KEY_new();
  	if (!ec)
  		return 0;
  	EVP_PKEY_assign_EC_KEY(pkey, ec);
  	/* Note: if error return, pkey is freed by parent routine */
  	if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
  		return 0;
  	return EC_KEY_generate_key(pkey->pkey.ec);
  	}
  
  const EVP_PKEY_METHOD ec_pkey_meth = 
  	{
  	EVP_PKEY_EC,
  	0,
  	pkey_ec_init,
  	pkey_ec_copy,
  	pkey_ec_cleanup,
  
  	0,
  	pkey_ec_paramgen,
  
  	0,
  	pkey_ec_keygen,
  
  	0,
  	pkey_ec_sign,
  
  	0,
  	pkey_ec_verify,
  
  	0,0,
  
  	0,0,0,0,
  
  	0,0,
  
  	0,0,
  
  	0,
  	pkey_ec_derive,
  
  	pkey_ec_ctrl,
  	pkey_ec_ctrl_str
  
  	};
  