Add X25519 and Ed25519 support.
(Ed25519 support is disabled when |OPENSSL_SMALL| is defined.)
libcrypto.a sizes:
x86-64 -O3 -march=native: +78012 (1584902 → 1662914)
x86-64 -O3 -march=native -DOPENSSL_SMALL: +10596 (1356206 → 1366802)
Android armv7 Thumb -O2 -DOPENSSL_SMALL: +13132 (1258462 → 1271594)
Change-Id: I6a7e64d481e4ce4daa7d5057578081358746cfb9
Reviewed-on: https://boringssl-review.googlesource.com/6497
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/curve25519.h b/include/openssl/curve25519.h
new file mode 100644
index 0000000..572272d
--- /dev/null
+++ b/include/openssl/curve25519.h
@@ -0,0 +1,88 @@
+/* Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#ifndef OPENSSL_HEADER_CURVE25519_H
+#define OPENSSL_HEADER_CURVE25519_H
+
+#include <openssl/base.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+/* Curve25519.
+ *
+ * Curve25519 is an elliptic curve. See
+ * https://tools.ietf.org/html/draft-irtf-cfrg-curves-11. */
+
+
+/* X25519.
+ *
+ * Curve25519 is an elliptic curve. The same name is also sometimes used for
+ * the Diffie-Hellman primitive built from it but “X25519” is a more precise
+ * name for that, which is the one used here. See http://cr.yp.to/ecdh.html and
+ * https://tools.ietf.org/html/draft-irtf-cfrg-curves-11. */
+
+/* X25519_keypair sets |out_public_value| and |out_private_key| to a freshly
+ * generated, public–private key pair. */
+OPENSSL_EXPORT void X25519_keypair(uint8_t out_public_value[32],
+ uint8_t out_private_key[32]);
+
+/* X25519 writes a shared key to |out_shared_key| that is calculated from the
+ * given private key and the peer's public value. It returns one on success and
+ * zero on error.
+ *
+ * Don't use the shared key directly, rather use a KDF and also include the two
+ * public values as inputs. */
+OPENSSL_EXPORT int X25519(uint8_t out_shared_key[32],
+ const uint8_t private_key[32],
+ const uint8_t peers_public_value[32]);
+
+/* X25519_public_from_private calculates a Diffie-Hellman public value from the
+ * given private key and writes it to |out_public_value|. */
+OPENSSL_EXPORT void X25519_public_from_private(uint8_t out_public_value[32],
+ const uint8_t private_key[32]);
+
+
+/* Ed25519.
+ *
+ * Ed25519 is a signature scheme using a twisted-Edwards curve that is
+ * birationally equivalent to curve25519. */
+
+/* ED25519_keypair sets |out_public_key| and |out_private_key| to a freshly
+ * generated, public–private key pair. */
+OPENSSL_EXPORT void ED25519_keypair(uint8_t out_public_key[32],
+ uint8_t out_private_key[64]);
+
+/* ED25519_sign sets |out_sig| to be a signature of |message_len| bytes from
+ * |message| using |private_key|. It returns one on success or zero on
+ * error. */
+OPENSSL_EXPORT int ED25519_sign(uint8_t out_sig[64], const uint8_t *message,
+ size_t message_len,
+ const uint8_t private_key[64]);
+
+/* ED25519_verify returns one iff |signature| is a valid signature, by
+ * |public_key| of |message_len| bytes from |message|. It returns zero
+ * otherwise. */
+OPENSSL_EXPORT int ED25519_verify(const uint8_t *message, size_t message_len,
+ const uint8_t signature[64],
+ const uint8_t public_key[32]);
+
+
+#if defined(__cplusplus)
+} /* extern C */
+#endif
+
+#endif /* OPENSSL_HEADER_CURVE25519_H */
