| /* |
| * 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 HEADER_CURVE25519_H |
| #define HEADER_CURVE25519_H |
| |
| #include <stdint.h> |
| |
| #include <openssl/opensslconf.h> |
| |
| #if defined(__cplusplus) |
| extern "C" { |
| #endif |
| |
| /* |
| * Curve25519. |
| * |
| * Curve25519 is an elliptic curve. See https://tools.ietf.org/html/rfc7748. |
| */ |
| |
| /* |
| * X25519. |
| * |
| * X25519 is the Diffie-Hellman primitive built from curve25519. It is |
| * sometimes referred to as curve25519, but X25519 is a more precise name. |
| * See http://cr.yp.to/ecdh.html and https://tools.ietf.org/html/rfc7748. |
| */ |
| |
| #define X25519_KEY_LENGTH 32 |
| |
| /* |
| * X25519_keypair sets |out_public_value| and |out_private_key| to a freshly |
| * generated, public/private key pair. |
| */ |
| void X25519_keypair(uint8_t out_public_value[X25519_KEY_LENGTH], |
| uint8_t out_private_key[X25519_KEY_LENGTH]); |
| |
| /* |
| * 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. |
| */ |
| int X25519(uint8_t out_shared_key[X25519_KEY_LENGTH], |
| const uint8_t private_key[X25519_KEY_LENGTH], |
| const uint8_t peers_public_value[X25519_KEY_LENGTH]); |
| |
| #if defined(__cplusplus) |
| } /* extern C */ |
| #endif |
| |
| #endif /* HEADER_CURVE25519_H */ |