I2P -> .NET

libdotnet/Siphash.h

@@ -0,0 +1,155 @@
+/**
+   This code is licensed under the MCGSI Public License
+   Copyright 2018 Jeff Becker
+
+   Kovri go write your own code
+
+ */
+#ifndef SIPHASH_H
+#define SIPHASH_H
+
+#include <cstdint>
+#include "Crypto.h"
+
+#if !OPENSSL_SIPHASH
+namespace dotnet
+{
+namespace crypto 
+{
+    namespace siphash
+    {
+        constexpr int crounds = 2;
+        constexpr int drounds = 4;
+
+        inline uint64_t rotl(const uint64_t & x, int b)
+        {
+            uint64_t ret = x << b;
+            ret |= x >> (64 - b);
+            return ret;
+        }
+
+        inline void u32to8le(const uint32_t & v, uint8_t * p)
+        {
+            p[0] = (uint8_t) v;
+            p[1] = (uint8_t) (v >> 8);
+            p[2] = (uint8_t) (v >> 16);
+            p[3] = (uint8_t) (v >> 24);
+        }
+
+        inline void u64to8le(const uint64_t & v, uint8_t * p)
+        {
+            p[0] = v & 0xff;
+            p[1] = (v >> 8)  & 0xff;
+            p[2] = (v >> 16) & 0xff;
+            p[3] = (v >> 24) & 0xff;
+            p[4] = (v >> 32) & 0xff;
+            p[5] = (v >> 40) & 0xff;
+            p[6] = (v >> 48) & 0xff;
+            p[7] = (v >> 56) & 0xff;
+        }
+
+        inline uint64_t u8to64le(const uint8_t * p)
+        {
+            uint64_t i = 0;
+            int idx = 0;
+            while(idx < 8)
+            {
+                i |= ((uint64_t) p[idx]) << (idx * 8);
+                ++idx;
+            }
+            return i;
+        }
+        
+        inline void round(uint64_t & _v0, uint64_t & _v1, uint64_t & _v2, uint64_t & _v3)
+        {
+            _v0 += _v1; 
+            _v1 = rotl(_v1, 13); 
+            _v1 ^= _v0;  
+            _v0 = rotl(_v0, 32); 
+            _v2 += _v3;  
+            _v3 = rotl(_v3, 16);  
+            _v3 ^= _v2;         
+            _v0 += _v3;                                                              
+            _v3 = rotl(_v3, 21);                                                     
+            _v3 ^= _v0;                                                              
+            _v2 += _v1;                                                              
+            _v1 = rotl(_v1, 17);                                                     
+            _v1 ^= _v2;                                                              
+            _v2 = rotl(_v2, 32); 
+        }
+    }
+   
+    /** hashsz must be 8 or 16 */
+    template<std::size_t hashsz>
+    inline void Siphash(uint8_t * h, const uint8_t * buf, std::size_t bufsz, const uint8_t * key)
+    {
+        uint64_t v0 = 0x736f6d6570736575ULL;
+        uint64_t v1 = 0x646f72616e646f6dULL;
+        uint64_t v2 = 0x6c7967656e657261ULL;
+        uint64_t v3 = 0x7465646279746573ULL;
+        const uint64_t k0 = siphash::u8to64le(key);
+        const uint64_t k1 = siphash::u8to64le(key + 8);
+        uint64_t msg;
+        int i;
+        const uint8_t * end = buf + bufsz - (bufsz % sizeof(uint64_t));
+        auto left = bufsz & 7;
+        uint64_t b = ((uint64_t)bufsz) << 56;
+        v3 ^= k1;
+        v2 ^= k0;
+        v1 ^= k1;
+        v0 ^= k0;
+
+        if(hashsz == 16) v1 ^= 0xee;
+
+        while(buf != end)
+        {
+            msg = siphash::u8to64le(buf);
+            v3 ^= msg;
+            for(i = 0; i < siphash::crounds; ++i)
+                siphash::round(v0, v1, v2, v3);
+            
+            v0 ^= msg;
+            buf += 8;
+        }
+
+        while(left)
+        {
+            --left;
+            b |= ((uint64_t)(buf[left])) << (left  * 8);
+        }
+
+        v3 ^= b;
+
+        for(i = 0; i < siphash::crounds; ++i)
+            siphash::round(v0, v1, v2, v3);
+
+        v0 ^= b;
+
+
+        if(hashsz == 16)
+            v2 ^= 0xee;
+        else
+            v2 ^= 0xff;
+
+        for(i = 0; i  < siphash::drounds; ++i)
+            siphash::round(v0, v1, v2, v3);
+
+        b = v0 ^ v1 ^ v2 ^ v3;
+
+        siphash::u64to8le(b, h);
+
+        if(hashsz == 8) return;
+
+        v1 ^= 0xdd;
+
+        for (i = 0; i < siphash::drounds; ++i)
+            siphash::round(v0, v1, v2, v3);
+
+        b = v0 ^ v1 ^ v2 ^ v3;
+        siphash::u64to8le(b, h + 8);
+    }
+}
+}
+#endif
+
+#endif