ECDSA with OpenSSL

src/libstrongswan/plugins/openssl/openssl_util.c

@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2008 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program 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 General Public License
+ * for more details.
+ *
+ * $Id$
+ */
+
+#include "openssl_util.h"
+
+#include <debug.h>
+
+#include <openssl/evp.h>
+
+/**
+ * Described in header.
+ */
+bool openssl_hash_chunk(int hash_type, chunk_t data, chunk_t *hash)
+{
+	EVP_MD_CTX *ctx;
+	bool ret = FALSE;
+	const EVP_MD *hasher = EVP_get_digestbynid(hash_type);
+	if (!hasher)
+	{
+		return FALSE;
+	}
+	
+	ctx = EVP_MD_CTX_create();	
+	if (!ctx)
+	{
+		goto error;
+	}
+	
+	if (!EVP_DigestInit_ex(ctx, hasher, NULL))
+	{
+		goto error;
+	}
+	
+	if (!EVP_DigestUpdate(ctx, data.ptr, data.len))
+	{
+		goto error;
+	}
+	
+	*hash = chunk_alloc(hasher->md_size);
+	if (!EVP_DigestFinal_ex(ctx, hash->ptr, NULL))
+	{
+		chunk_free(hash);
+		goto error;
+	}
+	
+	ret = TRUE;
+error:
+	if (ctx)
+	{
+		EVP_MD_CTX_destroy(ctx);
+	}
+	return ret;
+}
+
+/**
+ * Described in header.
+ */
+bool openssl_bn_cat(int len, BIGNUM *a, BIGNUM *b, chunk_t *chunk)
+{
+	int offset;
+	
+	chunk->len = len * 2;
+	chunk->ptr = malloc(chunk->len);
+	memset(chunk->ptr, 0, chunk->len);
+	
+	offset = len - BN_num_bytes(a);
+	if (!BN_bn2bin(a, chunk->ptr + offset))
+	{
+		goto error;
+	}
+	
+	offset = len - BN_num_bytes(b);
+	if (!BN_bn2bin(b, chunk->ptr + len + offset))
+	{
+		goto error;
+	}
+	
+	return TRUE;
+error:
+	chunk_free(chunk);
+	return FALSE;
+}
+
+
+/**
+ * Described in header.
+ */
+bool openssl_bn_split(chunk_t chunk, BIGNUM *a, BIGNUM *b)
+{
+	int len;
+	
+	if ((chunk.len % 2) != 0)
+	{
+		return FALSE;
+	}
+	
+	len = chunk.len / 2;
+	
+	if (!BN_bin2bn(chunk.ptr, len, a) ||
+		!BN_bin2bn(chunk.ptr + len, len, b))
+	{
+		return FALSE;
+	}
+	
+	return TRUE;
+}