Switch from encyrption to decryption in loop

Signed-off-by: Tom Kaitchuck <tom.kaitchuck@emc.com>

src/aes_hash.rs

@@ -81,15 +81,15 @@ impl AHasher {
 
     #[inline(always)]
     fn hash_in(&mut self, new_value: u128) {
-        self.enc = aesenc(self.enc, new_value);
+        self.enc = aesdec(self.enc, new_value);
         self.sum = shuffle_and_add(self.sum, new_value);
     }
 
     #[inline(always)]
     fn hash_in_2(&mut self, v1: u128, v2: u128) {
-        self.enc = aesenc(self.enc, v1);
+        self.enc = aesdec(self.enc, v1);
         self.sum = shuffle_and_add(self.sum, v1);
-        self.enc = aesenc(self.enc, v2);
+        self.enc = aesdec(self.enc, v2);
         self.sum = shuffle_and_add(self.sum, v2);
     }
 
@@ -174,10 +174,10 @@ impl Hasher for AHasher {
                     sum[1] = shuffle_and_add(sum[1], tail[3]);
                     while data.len() > 64 {
                         let (blocks, rest) = data.read_u128x4();
-                        current[0] = aesenc(current[0], blocks[0]);
-                        current[1] = aesenc(current[1], blocks[1]);
-                        current[2] = aesenc(current[2], blocks[2]);
-                        current[3] = aesenc(current[3], blocks[3]);
+                        current[0] = aesdec(current[0], blocks[0]);
+                        current[1] = aesdec(current[1], blocks[1]);
+                        current[2] = aesdec(current[2], blocks[2]);
+                        current[3] = aesdec(current[3], blocks[3]);
                         sum[0] = shuffle_and_add(sum[0], blocks[0]);
                         sum[1] = shuffle_and_add(sum[1], blocks[1]);
                         sum[0] = shuffle_and_add(sum[0], blocks[2]);