1 files changed, 104 insertions, 0 deletions
diff --git a/poly1305-ref.c b/poly1305-ref.c
new file mode 100644
index 0000000..288d2fa
--- /dev/null
+++ b/poly1305-ref.c
@@ -0,0 +1,104 @@
+/*
+20080912
+D. J. Bernstein
+Public domain.
+*/
+
+
+
+static void add(unsigned int h[17],const unsigned int c[17])
+{
+  unsigned int j;
+  unsigned int u;
+  u = 0;
+  for (j = 0;j < 17;++j) { u += h[j] + c[j]; h[j] = u & 255; u >>= 8; }
+}
+
+static void squeeze(unsigned int h[17])
+{
+  unsigned int j;
+  unsigned int u;
+  u = 0;
+  for (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 (j = 0;j < 16;++j) { u += h[j]; h[j] = u & 255; u >>= 8; }
+  u += h[16]; h[16] = u;
+}
+
+static const unsigned int minusp[17] = {
+  5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 252
+} ;
+
+static void freeze(unsigned int h[17])
+{
+  unsigned int horig[17];
+  unsigned int j;
+  unsigned int negative;
+  for (j = 0;j < 17;++j) horig[j] = h[j];
+  add(h,minusp);
+  negative = -(h[16] >> 7);
+  for (j = 0;j < 17;++j) h[j] ^= negative & (horig[j] ^ h[j]);
+}
+
+static void mulmod(unsigned int h[17],const unsigned int r[17])
+{
+  unsigned int hr[17];
+  unsigned int i;
+  unsigned int j;
+  unsigned int u;
+
+  for (i = 0;i < 17;++i) {
+    u = 0;
+    for (j = 0;j <= i;++j) u += h[j] * r[i - j];
+    for (j = i + 1;j < 17;++j) u += 320 * h[j] * r[i + 17 - j];
+    hr[i] = u;
+  }
+  for (i = 0;i < 17;++i) h[i] = hr[i];
+  squeeze(h);
+}
+
+int poly1305_ref(unsigned char *out,const unsigned char *in,unsigned long long inlen,const unsigned char *k)
+{
+  unsigned int j;
+  unsigned int r[17];
+  unsigned int h[17];
+  unsigned int c[17];
+
+  r[0] = k[0];
+  r[1] = k[1];
+  r[2] = k[2];
+  r[3] = k[3] & 15;
+  r[4] = k[4] & 252;
+  r[5] = k[5];
+  r[6] = k[6];
+  r[7] = k[7] & 15;
+  r[8] = k[8] & 252;
+  r[9] = k[9];
+  r[10] = k[10];
+  r[11] = k[11] & 15;
+  r[12] = k[12] & 252;
+  r[13] = k[13];
+  r[14] = k[14];
+  r[15] = k[15] & 15;
+  r[16] = 0;
+
+  for (j = 0;j < 17;++j) h[j] = 0;
+
+  while (inlen > 0) {
+    for (j = 0;j < 17;++j) c[j] = 0;
+    for (j = 0;(j < 16) && (j < inlen);++j) c[j] = in[j];
+    c[j] = 1;
+    in += j; inlen -= j;
+    add(h,c);
+    mulmod(h,r);
+  }
+
+  freeze(h);
+
+  for (j = 0;j < 16;++j) c[j] = k[j + 16];
+  c[16] = 0;
+  add(h,c);
+  for (j = 0;j < 16;++j) out[j] = h[j];
+  return 0;
+}