ntcp2 crypto added

libi2pd/ChaCha20.cpp

@@ -0,0 +1,147 @@
+#include "ChaCha20.h"
+
+/**
+   This code is licensed under the MCGSI Public License
+   Copyright 2018 Jeff Becker
+
+   Kovri go write your own code
+
+ */
+namespace i2p
+{
+namespace crypto
+{
+namespace chacha
+{
+constexpr int rounds = 20;
+constexpr std::size_t blocksize = 64;
+
+void u32t8le(uint32_t v, uint8_t * p) 
+{
+    p[0] = v & 0xff;
+    p[1] = (v >> 8) & 0xff;
+    p[2] = (v >> 16) & 0xff;
+    p[3] = (v >> 24) & 0xff;
+}
+
+uint32_t u8t32le(const uint8_t * p) 
+{
+    uint32_t value = p[3];
+
+    value = (value << 8) | p[2];
+    value = (value << 8) | p[1];
+    value = (value << 8) | p[0];
+
+    return value;
+}
+
+uint32_t rotl32(uint32_t x, int n) 
+{
+    return x << n | (x >> (-n & 31));
+}
+
+void quarterround(uint32_t *x, int a, int b, int c, int d) 
+{
+    x[a] += x[b]; x[d] = rotl32(x[d] ^ x[a], 16);
+    x[c] += x[d]; x[b] = rotl32(x[b] ^ x[c], 12);
+    x[a] += x[b]; x[d] = rotl32(x[d] ^ x[a],  8);
+    x[c] += x[d]; x[b] = rotl32(x[b] ^ x[c],  7);
+}
+
+    struct State_t
+    {
+      State_t() {};
+      State_t(State_t &&) = delete;
+      
+      State_t & operator += (const State_t & other)
+      {
+        for(int i = 0; i < 16; i++)
+            data[i] += other.data[i];
+        return *this;
+      }
+
+      void Copy(const State_t & other)
+      {
+           memcpy(data, other.data, sizeof(uint32_t) * 16);
+      }
+      uint32_t data[16];
+    };
+
+    struct Block_t
+    {
+      Block_t() {};
+      Block_t(Block_t &&) = delete;
+
+      uint8_t data[blocksize];
+
+      void operator << (const State_t & st)
+      {
+        int i;
+        for (i = 0; i < 16; i++) 
+            u32t8le(st.data[i], data + (i << 2));
+      }
+    };
+
+void block(const State_t &input, Block_t & block, int rounds)
+{
+    int i;
+    State_t x;
+    x.Copy(input);
+
+    for (i = rounds; i > 0; i -= 2) 
+    {
+        quarterround(x.data, 0, 4,  8, 12);
+        quarterround(x.data, 1, 5,  9, 13);
+        quarterround(x.data, 2, 6, 10, 14);
+        quarterround(x.data, 3, 7, 11, 15);
+        quarterround(x.data, 0, 5, 10, 15);
+        quarterround(x.data, 1, 6, 11, 12);
+        quarterround(x.data, 2, 7,  8, 13);
+        quarterround(x.data, 3, 4,  9, 14);
+    }
+    x += input;
+    block << x;
+
+}
+} // namespace chacha
+
+
+
+
+
+void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
+{
+    chacha::State_t state;
+    chacha::Block_t block;
+    size_t i, j;
+
+    state.data[0] = 0x61707865;
+    state.data[1] = 0x3320646e;
+    state.data[2] = 0x79622d32;
+    state.data[3] = 0x6b206574;
+
+    for (i = 0; i < 8; i++) 
+        state.data[4 + i] = chacha::u8t32le(key + i * 4);
+    
+
+    state.data[12] = counter;
+
+    for (i = 0; i < 3; i++) 
+        state.data[13 + i] = chacha::u8t32le(nonce + i * 4);
+
+    
+    for (i = 0; i < sz; i += chacha::blocksize) 
+    {
+        chacha::block(state, block, chacha::rounds);
+        state.data[12]++;
+        for (j = i; j < i + chacha::blocksize; j++) 
+        {
+            if (j >= sz) break;
+            buf[j] ^= block.data[j - i];
+        }
+    }
+
+}
+
+}
+}