Diff: wolfcrypt/src/curve25519.c

Revision:

0:d92f9d21154c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wolfcrypt/src/curve25519.c	Fri Jun 26 00:39:20 2015 +0000
@@ -0,0 +1,261 @@
+/* curve25519.c
+ *
+ * Copyright (C) 2006-2015 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL. (formerly known as CyaSSL)
+ *
+ * wolfSSL 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.
+ *
+ * wolfSSL 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+ /* Based On Daniel J Bernstein's curve25519 Public Domain ref10 work. */
+
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+#include <wolfssl/wolfcrypt/settings.h>
+
+#ifdef HAVE_CURVE25519
+
+#include <wolfssl/wolfcrypt/curve25519.h>
+#include <wolfssl/wolfcrypt/error-crypt.h>
+#ifdef NO_INLINE
+    #include <wolfssl/wolfcrypt/misc.h>
+#else
+    #include <wolfcrypt/src/misc.c>
+#endif
+
+const curve25519_set_type curve25519_sets[] = {
+{
+        32,
+        "CURVE25519",
+}
+};
+
+
+
+int wc_curve25519_make_key(RNG* rng, int keysize, curve25519_key* key)
+{
+  unsigned char basepoint[CURVE25519_KEYSIZE] = {9};
+  unsigned char n[CURVE25519_KEYSIZE];
+  unsigned char p[CURVE25519_KEYSIZE];
+  int  i;
+  int  ret;
+
+  if (key == NULL || rng == NULL)
+      return ECC_BAD_ARG_E;
+
+  /* currently only a key size of 32 bytes is used */
+  if (keysize != CURVE25519_KEYSIZE)
+      return ECC_BAD_ARG_E;
+
+  /* get random number from RNG */
+  ret = wc_RNG_GenerateBlock(rng, n, keysize);
+  if (ret != 0)
+      return ret;
+
+  for (i = 0; i < keysize; ++i) key->k.point[i] = n[i];
+  key->k.point[ 0] &= 248;
+  key->k.point[31] &= 127;
+  key->k.point[31] |= 64;
+
+  /* compute public key */
+  ret = curve25519(p, key->k.point, basepoint);
+
+  /* store keys in big endian format */
+  for (i = 0; i < keysize; ++i) n[i] = key->k.point[i];
+  for (i = 0; i < keysize; ++i) {
+      key->p.point[keysize - i - 1] = p[i];
+      key->k.point[keysize - i - 1] = n[i];
+  }
+
+  ForceZero(n, keysize);
+  ForceZero(p, keysize);
+
+  return ret;
+}
+
+
+int wc_curve25519_shared_secret(curve25519_key* private_key,
+                                curve25519_key* public_key,
+                                byte* out, word32* outlen)
+{
+    unsigned char k[CURVE25519_KEYSIZE];
+    unsigned char p[CURVE25519_KEYSIZE];
+    unsigned char o[CURVE25519_KEYSIZE];
+    int ret = 0;
+    int i;
+
+    /* sanity check */
+    if (private_key == NULL || public_key == NULL || out == NULL ||
+            outlen == NULL)
+        return BAD_FUNC_ARG;
+
+    /* avoid implementation fingerprinting */
+    if (public_key->p.point[0] > 0x7F)
+        return ECC_BAD_ARG_E;
+
+    XMEMSET(p,   0, sizeof(p));
+    XMEMSET(k,   0, sizeof(k));
+    XMEMSET(out, 0, CURVE25519_KEYSIZE);
+
+    for (i = 0; i < CURVE25519_KEYSIZE; ++i) {
+        p[i] = public_key->p.point [CURVE25519_KEYSIZE - i - 1];
+        k[i] = private_key->k.point[CURVE25519_KEYSIZE - i - 1];
+    }
+
+    ret     = curve25519(o , k, p);
+    *outlen = CURVE25519_KEYSIZE;
+
+    for (i = 0; i < CURVE25519_KEYSIZE; ++i) {
+        out[i] = o[CURVE25519_KEYSIZE - i -1];
+    }
+
+    ForceZero(p, sizeof(p));
+    ForceZero(k, sizeof(k));
+    ForceZero(o, sizeof(o));
+
+    return ret;
+}
+
+
+/* curve25519 uses a serialized string for key representation */
+int wc_curve25519_export_public(curve25519_key* key, byte* out, word32* outLen)
+{
+    word32 keySz;
+
+    if (key == NULL || out == NULL || outLen == NULL)
+        return BAD_FUNC_ARG;
+
+    /* check size of outgoing key */
+    keySz  = wc_curve25519_size(key);
+
+    /* copy in public key */
+    XMEMCPY(out, key->p.point, keySz);
+    *outLen = keySz;
+
+    return 0;
+}
+
+/* import curve25519 public key
+   return 0 on success */
+int wc_curve25519_import_public(const byte* in, word32 inLen,
+                                curve25519_key* key)
+{
+    word32 keySz;
+
+    /* sanity check */
+    if (key == NULL || in == NULL)
+        return ECC_BAD_ARG_E;
+
+    /* check size of incoming keys */
+    keySz = wc_curve25519_size(key);
+    if (inLen != keySz)
+       return ECC_BAD_ARG_E;
+
+    XMEMCPY(key->p.point, in, inLen);
+
+    key->dp = &curve25519_sets[0];
+
+    return 0;
+}
+
+
+/* export curve25519 private key only raw, outLen is in/out size
+   return 0 on success */
+int wc_curve25519_export_private_raw(curve25519_key* key, byte* out,
+                                     word32* outLen)
+{
+    word32 keySz;
+
+    /* sanity check */
+    if (key == NULL || out == NULL || outLen == NULL)
+        return ECC_BAD_ARG_E;
+
+    keySz = wc_curve25519_size(key);
+    *outLen = keySz;
+    XMEMSET(out, 0, keySz);
+    XMEMCPY(out, key->k.point, keySz);
+
+    return 0;
+}
+
+
+/* curve25519 private key import.
+   Public key to match private key needs to be imported too */
+int wc_curve25519_import_private_raw(const byte* priv, word32 privSz,
+                             const byte* pub, word32 pubSz, curve25519_key* key)
+{
+    int ret = 0;
+    word32 keySz;
+
+    /* sanity check */
+    if (key == NULL || priv == NULL || pub == NULL)
+        return ECC_BAD_ARG_E;
+
+    /* check size of incoming keys */
+    keySz = wc_curve25519_size(key);
+    if (privSz != keySz || pubSz != keySz)
+       return ECC_BAD_ARG_E;
+
+    XMEMCPY(key->k.point, priv, privSz);
+    XMEMCPY(key->p.point, pub, pubSz);
+
+    return ret;
+}
+
+
+int wc_curve25519_init(curve25519_key* key)
+{
+    word32 keySz;
+
+    if (key == NULL)
+       return ECC_BAD_ARG_E;
+
+    /* currently the format for curve25519 */
+    key->dp = &curve25519_sets[0];
+    keySz   = key->dp->size;
+
+    XMEMSET(key->k.point, 0, keySz);
+    XMEMSET(key->p.point, 0, keySz);
+
+    return 0;
+}
+
+
+/* Clean the memory of a key */
+void wc_curve25519_free(curve25519_key* key)
+{
+   if (key == NULL)
+       return;
+
+   key->dp = NULL;
+   ForceZero(key->p.point, sizeof(key->p.point));
+   ForceZero(key->k.point, sizeof(key->k.point));
+}
+
+
+/* get key size */
+int wc_curve25519_size(curve25519_key* key)
+{
+    if (key == NULL) return 0;
+
+    return key->dp->size;
+}
+
+#endif /*HAVE_CURVE25519*/
+
+