Merge #15512: Add ChaCha20 encryption option (XOR)

2dfe27517 Add ChaCha20 bench (Jonas Schnelli)
2bc2b8b49 Add ChaCha20 encryption option (XOR) (Jonas Schnelli)

Pull request description:

  The current ChaCha20 implementation does not support message encryption (it can only output the keystream which is sufficient for the RNG).

  This PR adds the actual XORing of the `plaintext` with the `keystream` in order to return the desired `ciphertext`.

  Required for v2 message transport protocol.

ACKs for commit 2dfe27:
  jnewbery:
    Looks good. utACK 2dfe2751713c814aea53b5a7563eb74ad1baea00.
  jnewbery:
    utACK 2dfe2751713c814aea53b5a7563eb74ad1baea00
  sipa:
    utACK 2dfe2751713c814aea53b5a7563eb74ad1baea00
  ryanofsky:
    utACK 2dfe2751713c814aea53b5a7563eb74ad1baea00. Changes since last review are just renaming the Crypt method, adding comments, and simplifying the benchmark.

Tree-SHA512: 84bb234da2ca9fdc44bc29a786d9dd215520f81245270c1aef801ef66b6091b7793e2eb38ad6dbb084925245065c5dce9e5582f2d0fa220ab3e182d43412d5b5

1 files changed, 46 insertions, 0 deletions

diff --git a/src/bench/chacha20.cpp b/src/bench/chacha20.cpp
new file mode 100644
index 0000000000..69d8c96ec0
--- /dev/null
+++ b/src/bench/chacha20.cpp
@@ -0,0 +1,46 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <iostream>
+
+#include <bench/bench.h>
+#include <hash.h>
+#include <crypto/chacha20.h>
+
+/* Number of bytes to process per iteration */
+static const uint64_t BUFFER_SIZE_TINY  = 64;
+static const uint64_t BUFFER_SIZE_SMALL = 256;
+static const uint64_t BUFFER_SIZE_LARGE = 1024*1024;
+
+static void CHACHA20(benchmark::State& state, size_t buffersize)
+{
+    std::vector<uint8_t> key(32,0);
+    ChaCha20 ctx(key.data(), key.size());
+    ctx.SetIV(0);
+    ctx.Seek(0);
+    std::vector<uint8_t> in(buffersize,0);
+    std::vector<uint8_t> out(buffersize,0);
+    while (state.KeepRunning()) {
+        ctx.Crypt(in.data(), out.data(), in.size());
+    }
+}
+
+static void CHACHA20_64BYTES(benchmark::State& state)
+{
+    CHACHA20(state, BUFFER_SIZE_TINY);
+}
+
+static void CHACHA20_256BYTES(benchmark::State& state)
+{
+    CHACHA20(state, BUFFER_SIZE_SMALL);
+}
+
+static void CHACHA20_1MB(benchmark::State& state)
+{
+    CHACHA20(state, BUFFER_SIZE_LARGE);
+}
+
+BENCHMARK(CHACHA20_64BYTES, 500000);
+BENCHMARK(CHACHA20_256BYTES, 250000);
+BENCHMARK(CHACHA20_1MB, 340);