view libtomcrypt/src/modes/xts/xts_mult_x.c @ 1705:5b701bf529aa

Fix ChaCha20 on 32-bit platforms (#99) * Fix ChaCha20 on 32-bit platforms On 32-bit platforms with old compiler STORE64H() parameter is not auto-expanded to 64-bit value, causing wrong IV data. Spotted on BCM4706 MIPS32r2 with GCC 4.2.4: Exit before auth: Integrity error (bad packet size 2065808956) * Fix Chacha20-Poly1305 and AES-GCM debug messages Functions were renamed earlier and trace messages - not.
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Fri, 29 May 2020 18:26:22 +0500
parents 6dba84798cd5
children
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */
#include "tomcrypt.h"

/**
  Source donated by Elliptic Semiconductor Inc (www.ellipticsemi.com) to the LibTom Projects
*/

#ifdef LTC_XTS_MODE

/** multiply by x
  @param I      The value to multiply by x (LFSR shift)
*/
void xts_mult_x(unsigned char *I)
{
   int x;
   unsigned char t, tt;

   for (x = t = 0; x < 16; x++) {
      tt = I[x] >> 7;
      I[x] = ((I[x] << 1) | t) & 0xFF;
      t = tt;
   }
   if (tt) {
      I[0] ^= 0x87;
   }
}

#endif

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