1 files changed, 127 insertions, 0 deletions
diff --git a/lib/ecc.c b/lib/ecc.c
new file mode 100644
index 0000000..b4d7a23
--- /dev/null
+++ b/lib/ecc.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2011-2012 Free Software Foundation, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>
+ *
+ */
+
+/* Helper functions for ECC handling 
+ * based on public domain code by Tom St. Dennis.
+ */
+#include "gnutls_int.h"
+#include <mpi.h>
+#include <ecc.h>
+#include <algorithms.h>
+#include "errors.h"
+
+int
+_gnutls_ecc_ansi_x962_export(gnutls_ecc_curve_t curve, bigint_t x,
+			     bigint_t y, gnutls_datum_t * out)
+{
+	int numlen = gnutls_ecc_curve_get_size(curve);
+	int byte_size, ret;
+	size_t size;
+
+	if (numlen == 0)
+		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+
+	out->size = 1 + 2 * numlen;
+
+	out->data = gnutls_malloc(out->size);
+	if (out->data == NULL)
+		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
+
+	memset(out->data, 0, out->size);
+
+	/* store byte 0x04 */
+	out->data[0] = 0x04;
+
+	/* pad and store x */
+	byte_size = (_gnutls_mpi_get_nbits(x) + 7) / 8;
+	if (numlen < byte_size) {
+		ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+		goto cleanup;
+	}
+
+	size = out->size - (1 + (numlen - byte_size));
+	ret =
+	    _gnutls_mpi_print(x, &out->data[1 + (numlen - byte_size)],
+			      &size);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	byte_size = (_gnutls_mpi_get_nbits(y) + 7) / 8;
+	if (numlen < byte_size) {
+		ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+		goto cleanup;
+	}
+
+	size = out->size - (1 + (numlen + numlen - byte_size));
+	ret =
+	    _gnutls_mpi_print(y,
+			      &out->data[1 + numlen + numlen - byte_size],
+			      &size);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	/* pad and store y */
+	return 0;
+ cleanup:
+	_gnutls_free_datum(out);
+	return ret;
+}
+
+
+
+int
+_gnutls_ecc_ansi_x962_import(const uint8_t * in,
+			     unsigned long inlen, bigint_t * x,
+			     bigint_t * y)
+{
+	int ret;
+
+	/* must be odd */
+	if ((inlen & 1) == 0) {
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	/* check for 4  */
+	if (in[0] != 4) {
+		return gnutls_assert_val(GNUTLS_E_PARSING_ERROR);
+	}
+
+	/* read data */
+	ret = _gnutls_mpi_init_scan(x, in + 1, (inlen - 1) >> 1);
+	if (ret < 0)
+		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
+
+	ret =
+	    _gnutls_mpi_init_scan(y, in + 1 + ((inlen - 1) >> 1),
+			     (inlen - 1) >> 1);
+	if (ret < 0) {
+		_gnutls_mpi_release(x);
+		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
+	}
+
+	return 0;
+}
+