(struct aes_table): New subtable idx_shift.

Updated tables in aes_encrypt.c and aes_decrypt.c.

Rev: src/nettle/aes-decrypt.c:1.2
Rev: src/nettle/aes-encrypt.c:1.2
Rev: src/nettle/aes-internal.h:1.6

aes-decrypt.c

@@ -68,6 +68,10 @@ _aes_decrypt_table =
       { 3, 0, 1, 2 },
       { 2, 3, 0, 1 },
       { 1, 2, 3, 0 } },
+    { /* idx_shift */
+      { 3 * IDX_FACTOR, 0 * IDX_FACTOR, 1 * IDX_FACTOR, 2 * IDX_FACTOR },
+      { 2 * IDX_FACTOR, 3 * IDX_FACTOR, 0 * IDX_FACTOR, 1 * IDX_FACTOR },
+      { 1 * IDX_FACTOR, 2 * IDX_FACTOR, 3 * IDX_FACTOR, 0 * IDX_FACTOR } },
     { /* itable */
       { 
 	0x50a7f451,0x5365417e,0xc3a4171a,0x965e273a,

aes-encrypt.c

@@ -79,6 +79,10 @@ _aes_encrypt_table =
       { 1, 2, 3, 0 },
       { 2, 3, 0, 1 },
       { 3, 0, 1, 2 } },
+    { /* idx_shift */
+      { 1 * IDX_FACTOR, 2 * IDX_FACTOR, 3 * IDX_FACTOR, 0 * IDX_FACTOR },
+      { 2 * IDX_FACTOR, 3 * IDX_FACTOR, 0 * IDX_FACTOR, 1 * IDX_FACTOR },
+      { 3 * IDX_FACTOR, 0 * IDX_FACTOR, 1 * IDX_FACTOR, 2 * IDX_FACTOR } },
     { /* dtable */
       { 
 	0xa56363c6,0x847c7cf8,0x997777ee,0x8d7b7bf6,

aes-internal.h

@@ -39,10 +39,15 @@
 # define AES_TABLE_SIZE 4
 #endif
 
+#define IDX_FACTOR 4
 struct aes_table
 {
   uint8_t sbox[0x100];
   unsigned idx[3][4];
+
+  /* Preshifted indices, multiplied by IDX_FACTOR */
+  unsigned idx_shift[3][4];
+
   uint32_t table[AES_TABLE_SIZE][0x100];
 };