--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NaCl/crypto_onetimeauth/poly1305.cs	Mon Apr 15 00:43:48 2013 +0200
@@ -0,0 +1,113 @@
+using System;
+
+namespace UCIS.NaCl.crypto_onetimeauth {
+	unsafe static class poly1305 {
+		static Boolean UseNativeFunctions = false;
+		static unsafe internal Boolean EnableNativeImplementation() {
+			UseNativeFunctions = false;
+			Byte* dummy = stackalloc Byte[32];
+			try {
+				if (Native.crypto_onetimeauth_poly1305(dummy, dummy, 0, dummy) != 0) return false;
+			} catch (Exception) {
+				return false;
+			}
+			return UseNativeFunctions = true;
+		}
+
+		const int CRYPTO_BYTES = 16;
+		const int CRYPTO_KEYBYTES = 32;
+
+		//Never written to
+		static UInt32[] minusp = new UInt32[17] { 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 252 };
+
+		public static int crypto_onetimeauth_verify(Byte* h, Byte* inv, UInt64 inlen, Byte* k) {
+			Byte* correct = stackalloc Byte[16];
+			crypto_onetimeauth(correct, inv, inlen, k);
+			return crypto_verify._16.crypto_verify(h, correct);
+		}
+
+		static void add(UInt32* h, UInt32* c) { //h[17], c[17]
+			UInt32 u = 0;
+			for (int j = 0; j < 17; ++j) { u += h[j] + c[j]; h[j] = u & 255; u >>= 8; }
+		}
+
+		static void squeeze(UInt32* h) { //h[17]
+			UInt32 u = 0;
+			for (int j = 0; j < 16; ++j) { u += h[j]; h[j] = u & 255; u >>= 8; }
+			u += h[16]; h[16] = u & 3;
+			u = 5 * (u >> 2);
+			for (int j = 0; j < 16; ++j) { u += h[j]; h[j] = u & 255; u >>= 8; }
+			u += h[16]; h[16] = u;
+		}
+
+		static void freeze(UInt32* h) { //h[17]
+			UInt32* horig = stackalloc UInt32[17];
+			for (int j = 0; j < 17; ++j) horig[j] = h[j];
+			fixed (uint* minuspp = minusp) add(h, minuspp);
+			UInt32 negative = (UInt32)(-(h[16] >> 7));
+			for (int j = 0; j < 17; ++j) h[j] ^= negative & (horig[j] ^ h[j]);
+		}
+
+		static void mulmod(UInt32* h, UInt32* r) { //h[17], r[17]
+			UInt32* hr = stackalloc UInt32[17];
+			for (uint i = 0; i < 17; ++i) {
+				UInt32 u = 0;
+				for (uint j = i + 1; j < 17; ++j) u += h[j] * r[i + 17 - j];
+				u *= 320;
+				for (uint j = 0; j <= i; ++j) u += h[j] * r[i - j];
+				hr[i] = u;
+			}
+			for (int i = 0; i < 17; ++i) h[i] = hr[i];
+			squeeze(h);
+		}
+
+		public static void crypto_onetimeauth(Byte* outv, Byte* inv, UInt64 inlen, Byte* k) {
+			if (UseNativeFunctions) {
+				Native.crypto_onetimeauth_poly1305(outv, inv, inlen, k);
+				return;
+			}
+
+			UInt32* r = stackalloc UInt32[17];
+			UInt32* h = stackalloc UInt32[17];
+			UInt32* c = stackalloc UInt32[17];
+
+			r[0] = k[0];
+			r[1] = k[1];
+			r[2] = k[2];
+			r[3] = (UInt32)(k[3] & 15);
+			r[4] = (UInt32)(k[4] & 252);
+			r[5] = k[5];
+			r[6] = k[6];
+			r[7] = (UInt32)(k[7] & 15);
+			r[8] = (UInt32)(k[8] & 252);
+			r[9] = k[9];
+			r[10] = k[10];
+			r[11] = (UInt32)(k[11] & 15);
+			r[12] = (UInt32)(k[12] & 252);
+			r[13] = k[13];
+			r[14] = k[14];
+			r[15] = (UInt32)(k[15] & 15);
+			r[16] = 0;
+
+			for (int j = 0; j < 17; ++j) h[j] = 0;
+
+			while (inlen > 0) {
+				int m = (int)Math.Min(16, inlen);
+				for (int j = 0; j < m; ++j) c[j] = inv[j];
+				c[m] = 1;
+				inv += m;
+				inlen -= (ulong)m;
+				for (int j = m + 1; j < 17; ++j) c[j] = 0;
+				add(h, c);
+				mulmod(h, r);
+			}
+
+			freeze(h);
+
+			for (int j = 0; j < 16; ++j) c[j] = k[j + 16];
+			c[16] = 0;
+			add(h, c);
+			for (int j = 0; j < 16; ++j) outv[j] = (Byte)h[j];
+		}
+	}
+}
\ No newline at end of file