Add a chacha20 variant to go with chacha8

1 files changed, 84 insertions, 0 deletions

diff --git a/src/crypto/chacha.h b/src/crypto/chacha.h
new file mode 100644
index 000000000..a9665030d
--- /dev/null
+++ b/src/crypto/chacha.h
@@ -0,0 +1,84 @@
+// Copyright (c) 2014-2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// 
+// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
+
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+#define CHACHA_KEY_SIZE 32
+#define CHACHA_IV_SIZE 8
+
+#if defined(__cplusplus)
+#include <memory.h>
+
+#include "common/memwipe.h"
+#include "hash.h"
+
+namespace crypto {
+  extern "C" {
+#endif
+    void chacha8(const void* data, size_t length, const uint8_t* key, const uint8_t* iv, char* cipher);
+    void chacha20(const void* data, size_t length, const uint8_t* key, const uint8_t* iv, char* cipher);
+#if defined(__cplusplus)
+  }
+
+  using chacha_key = tools::scrubbed_arr<uint8_t, CHACHA_KEY_SIZE>;
+
+#pragma pack(push, 1)
+  // MS VC 2012 doesn't interpret `class chacha_iv` as POD in spite of [9.0.10], so it is a struct
+  struct chacha_iv {
+    uint8_t data[CHACHA_IV_SIZE];
+  };
+#pragma pack(pop)
+
+  static_assert(sizeof(chacha_key) == CHACHA_KEY_SIZE && sizeof(chacha_iv) == CHACHA_IV_SIZE, "Invalid structure size");
+
+  inline void chacha8(const void* data, std::size_t length, const chacha_key& key, const chacha_iv& iv, char* cipher) {
+    chacha8(data, length, key.data(), reinterpret_cast<const uint8_t*>(&iv), cipher);
+  }
+
+  inline void chacha20(const void* data, std::size_t length, const chacha_key& key, const chacha_iv& iv, char* cipher) {
+    chacha20(data, length, key.data(), reinterpret_cast<const uint8_t*>(&iv), cipher);
+  }
+
+  inline void generate_chacha_key(const void *data, size_t size, chacha_key& key) {
+    static_assert(sizeof(chacha_key) <= sizeof(hash), "Size of hash must be at least that of chacha_key");
+    tools::scrubbed_arr<char, HASH_SIZE> pwd_hash;
+    crypto::cn_slow_hash(data, size, pwd_hash.data());
+    memcpy(&key, pwd_hash.data(), sizeof(key));
+  }
+
+  inline void generate_chacha_key(std::string password, chacha_key& key) {
+    return generate_chacha_key(password.data(), password.size(), key);
+  }
+}
+
+#endif