static SSL_CTX *init_tls_ctx(EAP_TLS_CONF *conf)
{
	SSL_METHOD *meth;
	SSL_CTX *ctx;
	X509_STORE *certstore;
	int verify_mode = SSL_VERIFY_NONE;
	int ctx_options = 0;
	int type;

	/*
	 *	Bug fix
	 *	http://old.nabble.com/Backward-compatibility-of-private-key-files--td27937046.html
	 */
	OpenSSL_add_all_algorithms();

	/*
	 *	SHA256 is in all versions of OpenSSL, but isn't
	 *	initialized by default.  It's needed for WiMAX
	 *	certificates.
	 */
#ifdef HAVE_OPENSSL_EVP_SHA256
	EVP_add_digest(EVP_sha256());
#endif

	meth = SSLv23_method();	/* which is really "all known SSL / TLS methods".  Idiots. */
	ctx = SSL_CTX_new(meth);

	/*
	 * Identify the type of certificates that needs to be loaded
	 */
	if (conf->file_type) {
		type = SSL_FILETYPE_PEM;
	} else {
		type = SSL_FILETYPE_ASN1;
	}

	/*
	 * Set the password to load private key
	 */
	if (conf->private_key_password) {
#ifdef __APPLE__
		/*
		 * We don't want to put the private key password in eap.conf, so  check
		 * for our special string which indicates we should get the password
		 * programmatically.
		 */
		const char* special_string = "Apple:UseCertAdmin";
		if (strncmp(conf->private_key_password,
					special_string,
					strlen(special_string)) == 0)
		{
			char cmd[256];
			const long max_password_len = 128;
			snprintf(cmd, sizeof(cmd) - 1,
					 "/usr/sbin/certadmin --get-private-key-passphrase \"%s\"",
					 conf->private_key_file);

			DEBUG2("rlm_eap: Getting private key passphrase using command \"%s\"", cmd);

			FILE* cmd_pipe = popen(cmd, "r");
			if (!cmd_pipe) {
				radlog(L_ERR, "rlm_eap: %s command failed.	Unable to get private_key_password", cmd);
				radlog(L_ERR, "rlm_eap: Error reading private_key_file %s", conf->private_key_file);
				return NULL;
			}

			free(conf->private_key_password);
			conf->private_key_password = malloc(max_password_len * sizeof(char));
			if (!conf->private_key_password) {
				radlog(L_ERR, "rlm_eap: Can't malloc space for private_key_password");
				radlog(L_ERR, "rlm_eap: Error reading private_key_file %s", conf->private_key_file);
				pclose(cmd_pipe);
				return NULL;
			}

			fgets(conf->private_key_password, max_password_len, cmd_pipe);
			pclose(cmd_pipe);

			/* Get rid of newline at end of password. */
			conf->private_key_password[strlen(conf->private_key_password) - 1] = '\0';
			DEBUG2("rlm_eap:  Password from command = \"%s\"", conf->private_key_password);
		}
#endif
		SSL_CTX_set_default_passwd_cb_userdata(ctx, conf->private_key_password);
		SSL_CTX_set_default_passwd_cb(ctx, cbtls_password);
	}

	/*
	 *	Load our keys and certificates
	 *
	 *	If certificates are of type PEM then we can make use
	 *	of cert chain authentication using openssl api call
	 *	SSL_CTX_use_certificate_chain_file.  Please see how
	 *	the cert chain needs to be given in PEM from
	 *	openSSL.org
	 */
	if (type == SSL_FILETYPE_PEM) {
		if (!(SSL_CTX_use_certificate_chain_file(ctx, conf->certificate_file))) {
			radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
			radlog(L_ERR, "rlm_eap_tls: Error reading certificate file %s", conf->certificate_file);
			return NULL;
		}

	} else if (!(SSL_CTX_use_certificate_file(ctx, conf->certificate_file, type))) {
		radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
		radlog(L_ERR, "rlm_eap_tls: Error reading certificate file %s", conf->certificate_file);
		return NULL;
	}

	/* Load the CAs we trust */
	if (conf->ca_file || conf->ca_path) {
		if (!SSL_CTX_load_verify_locations(ctx, conf->ca_file, conf->ca_path)) {
			radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
			radlog(L_ERR, "rlm_eap_tls: Error reading Trusted root CA list %s",conf->ca_file );
			return NULL;
		}
	}
	if (conf->ca_file && *conf->ca_file) SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(conf->ca_file));
	if (!(SSL_CTX_use_PrivateKey_file(ctx, conf->private_key_file, type))) {
		radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
		radlog(L_ERR, "rlm_eap_tls: Error reading private key file %s", conf->private_key_file);
		return NULL;
	}

	/*
	 * Check if the loaded private key is the right one
	 */
	if (!SSL_CTX_check_private_key(ctx)) {
		radlog(L_ERR, "rlm_eap_tls: Private key does not match the certificate public key");
		return NULL;
	}

	/*
	 *	Set ctx_options
	 */
	ctx_options |= SSL_OP_NO_SSLv2;
   	ctx_options |= SSL_OP_NO_SSLv3;

#ifdef SSL_OP_NO_TLSv1_1
	if (conf->disable_tlsv1_1) ctx_options |= SSL_OP_NO_TLSv1_1;
#endif
#ifdef SSL_OP_NO_TLSv1_2
	if (conf->disable_tlsv1_2) ctx_options |= SSL_OP_NO_TLSv1_2;
#endif

#ifdef SSL_OP_NO_TICKET
	ctx_options |= SSL_OP_NO_TICKET ;
#endif

	/*
	 *	SSL_OP_SINGLE_DH_USE must be used in order to prevent
	 *	small subgroup attacks and forward secrecy. Always
	 *	using
	 *
	 *	SSL_OP_SINGLE_DH_USE has an impact on the computer
	 *	time needed during negotiation, but it is not very
	 *	large.
	 */
   	ctx_options |= SSL_OP_SINGLE_DH_USE;

	/*
	 *	SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS to work around issues
	 *	in Windows Vista client.
	 *	http://www.openssl.org/~bodo/tls-cbc.txt
	 *	http://www.nabble.com/(RADIATOR)-Radiator-Version-3.16-released-t2600070.html
	 */
   	ctx_options |= SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS;

	SSL_CTX_set_options(ctx, ctx_options);

	/*
	 *	TODO: Set the RSA & DH
	 *	SSL_CTX_set_tmp_rsa_callback(ctx, cbtls_rsa);
	 *	SSL_CTX_set_tmp_dh_callback(ctx, cbtls_dh);
	 */

	/*
	 *	Set eliptical curve crypto configuration.
	 */
#if OPENSSL_VERSION_NUMBER >= 0x0090800fL
#ifndef OPENSSL_NO_ECDH
	if (set_ecdh_curve(ctx, conf->ecdh_curve) < 0) {
		return NULL;
	}
#endif
#endif

	/*
	 *	set the message callback to identify the type of
	 *	message.  For every new session, there can be a
	 *	different callback argument.
	 *
	 *	SSL_CTX_set_msg_callback(ctx, cbtls_msg);
	 */

	/* Set Info callback */
	SSL_CTX_set_info_callback(ctx, cbtls_info);

	/*
	 *	Callbacks, etc. for session resumption.
	 */
	if (conf->session_cache_enable) {
		SSL_CTX_sess_set_new_cb(ctx, cbtls_new_session);
		SSL_CTX_sess_set_get_cb(ctx, cbtls_get_session);
		SSL_CTX_sess_set_remove_cb(ctx, cbtls_remove_session);

		SSL_CTX_set_quiet_shutdown(ctx, 1);
	}

	/*
	 *	Check the certificates for revocation.
	 */
#ifdef X509_V_FLAG_CRL_CHECK
	if (conf->check_crl) {
	  certstore = SSL_CTX_get_cert_store(ctx);
	  if (certstore == NULL) {
	    radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
	    radlog(L_ERR, "rlm_eap_tls: Error reading Certificate Store");
	    return NULL;
	  }
	  X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK);

	  if (conf->check_all_crl) {
		  X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK_ALL);
	  }
	}
#endif

	/*
	 *	Set verify modes
	 *	Always verify the peer certificate
	 */
	verify_mode |= SSL_VERIFY_PEER;
	verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
	verify_mode |= SSL_VERIFY_CLIENT_ONCE;
	SSL_CTX_set_verify(ctx, verify_mode, cbtls_verify);

	if (conf->verify_depth) {
		SSL_CTX_set_verify_depth(ctx, conf->verify_depth);
	}

	/* Load randomness */
	if (conf->random_file) {
		if (!(RAND_load_file(conf->random_file, 1024*1024))) {
			radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
			radlog(L_ERR, "rlm_eap_tls: Error loading randomness");
			return NULL;
		}
	}

	/*
	 * Set the cipher list if we were told to
	 */
	if (conf->cipher_list) {
		if (!SSL_CTX_set_cipher_list(ctx, conf->cipher_list)) {
			radlog(L_ERR, "rlm_eap_tls: Error setting cipher list");
			return NULL;
		}
	}

	/*
	 *	Setup session caching
	 */
	if (conf->session_cache_enable) {
		/*
		 *	Create a unique context Id per EAP-TLS configuration.
		 */
		if (conf->session_id_name) {
			snprintf(conf->session_context_id,
				 sizeof(conf->session_context_id),
				 "FR eap %s",
				 conf->session_id_name);
		} else {
			snprintf(conf->session_context_id,
				 sizeof(conf->session_context_id),
				 "FR eap %p", conf);
		}

		/*
		 *	Cache it, and DON'T auto-clear it.
		 */
		SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_SERVER | SSL_SESS_CACHE_NO_AUTO_CLEAR);

		SSL_CTX_set_session_id_context(ctx,
					       (unsigned char *) conf->session_context_id,
					       (unsigned int) strlen(conf->session_context_id));

		/*
		 *	Our timeout is in hours, this is in seconds.
		 */
		SSL_CTX_set_timeout(ctx, conf->session_timeout * 3600);

		/*
		 *	Set the maximum number of entries in the
		 *	session cache.
		 */
		SSL_CTX_sess_set_cache_size(ctx, conf->session_cache_size);

	} else {
		SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
	}

	/*
	 *	Register the application indices.  We can't use
	 *	hard-coded "0" and "1" as before, because we need to
	 *	set up a "free" handler for the cached session
	 *	information.
	 */
	if (eaptls_handle_idx < 0) {
		eaptls_handle_idx = SSL_get_ex_new_index(0, "eaptls_handle_idx",
							  NULL, NULL, NULL);
	}

	if (eaptls_conf_idx < 0) {
		eaptls_conf_idx = SSL_get_ex_new_index(0, "eaptls_conf_idx",
							  NULL, NULL, NULL);
	}

	if (eaptls_store_idx < 0) {
		eaptls_store_idx = SSL_get_ex_new_index(0, "eaptls_store_idx",
							  NULL, NULL, NULL);
	}

	if (eaptls_session_idx < 0) {
		eaptls_session_idx = SSL_SESSION_get_ex_new_index(0, "eaptls_session_idx",
							  NULL, NULL,
							  eaptls_session_free);
	}

	return ctx;
}