ntcp2 crypto added

libi2pd/ChaCha20.h

@@ -0,0 +1,26 @@
+/**
+   This code is licensed under the MCGSI Public License
+   Copyright 2018 Jeff Becker
+
+   Kovri go write your own code
+
+ */
+#ifndef LIBI2PD_CHACHA20_H
+#define LIBI2PD_CHACHA20_H
+#include <cstdint>
+#include <cstring>
+
+namespace i2p
+{
+namespace crypto
+{
+  const std::size_t CHACHA20_KEY_BYTES = 32;
+  const std::size_t CHACHA20_NOUNCE_BYTES = 12;
+
+  /** encrypt buf in place with chacha20 */
+  void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter=1);
+
+}
+}
+
+#endif