Correction du mode ΘCB3 quand sizeof(size_t)<8

Bug introduit par 3bb63d9.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/ref/lilliput-i.c b/src/ref/lilliput-i.c
index 3ba7ea2..11fdc45 100644
--- a/src/ref/lilliput-i.c
+++ b/src/ref/lilliput-i.c
@@ -42,7 +42,7 @@ static void _fill_msg_tweak(
     /* With an s-bit block index, the t-bit tweak is filled as follows:
      *
      * - bits [      1, t-|N|-4]: block index
-     *        [      1,       s]: actual 64-bit block index
+     *        [      1,       s]: actual block index
      *        [    s+1, t-|N|-4]: 0-padding
      * - bits [t-|N|-4,     t-4]: nonce
      * - bits [    t-3,       t]: 4-bit prefix
@@ -50,11 +50,12 @@ static void _fill_msg_tweak(
 
     copy_block_index(block_index, tweak);
 
-    tweak[sizeof(block_index)] = lower_nibble(N[0]) << 4;
+    size_t N_start = TWEAK_BYTES - NONCE_BYTES - 1;
+    tweak[N_start] = lower_nibble(N[0]) << 4;
 
     for (size_t i=1; i<NONCE_BYTES; i++)
     {
-        tweak[sizeof(block_index)+i] = lower_nibble(N[i]) << 4 ^ upper_nibble(N[i-1]);
+        tweak[N_start+i] = lower_nibble(N[i]) << 4 ^ upper_nibble(N[i-1]);
     }
 
     tweak[TWEAK_BYTES-1] = prefix << 4 ^ upper_nibble(N[NONCE_BYTES-1]);