Add Chacha20-Poly1305, AES128-GCM and AES256-GCM support (#93) * Add Chacha20-Poly1305 authenticated encryption * Add general AEAD approach. * Add [email protected] algo using LibTomCrypt chacha and poly1305 routines. Chacha20-Poly1305 is generally faster than AES256 on CPU w/o dedicated AES instructions, having the same key size. Compiling in will add ~5,5kB to binary size on x86-64. function old new delta chacha_crypt - 1397 +1397 _poly1305_block - 608 +608 poly1305_done - 595 +595 dropbear_chachapoly_crypt - 457 +457 .rodata 26976 27392 +416 poly1305_process - 290 +290 poly1305_init - 221 +221 chacha_setup - 218 +218 encrypt_packet 1068 1270 +202 dropbear_chachapoly_getlength - 147 +147 decrypt_packet 756 897 +141 chacha_ivctr64 - 137 +137 read_packet 543 637 +94 dropbear_chachapoly_start - 94 +94 read_kex_algos 792 880 +88 chacha_keystream - 69 +69 dropbear_mode_chachapoly - 48 +48 sshciphers 280 320 +40 dropbear_mode_none 24 48 +24 dropbear_mode_ctr 24 48 +24 dropbear_mode_cbc 24 48 +24 dropbear_chachapoly_mac - 24 +24 dropbear_chachapoly - 24 +24 gen_new_keys 848 854 +6 ------------------------------------------------------------------------------ (add/remove: 14/0 grow/shrink: 10/0 up/down: 5388/0) Total: 5388 bytes * Add AES128-GCM and AES256-GCM authenticated encryption * Add general AES-GCM mode. * Add [email protected] and [email protected] algo using LibTomCrypt gcm routines. AES-GCM is combination of AES CTR mode and GHASH, slower than AES-CTR on CPU w/o dedicated AES/GHASH instructions therefore disabled by default. Compiling in will add ~6kB to binary size on x86-64. function old new delta gcm_process - 1060 +1060 .rodata 26976 27808 +832 gcm_gf_mult - 820 +820 gcm_add_aad - 660 +660 gcm_shift_table - 512 +512 gcm_done - 471 +471 gcm_add_iv - 384 +384 gcm_init - 347 +347 dropbear_gcm_crypt - 309 +309 encrypt_packet 1068 1270 +202 decrypt_packet 756 897 +141 gcm_reset - 118 +118 read_packet 543 637 +94 read_kex_algos 792 880 +88 sshciphers 280 360 +80 gcm_mult_h - 80 +80 dropbear_gcm_start - 62 +62 dropbear_mode_gcm - 48 +48 dropbear_mode_none 24 48 +24 dropbear_mode_ctr 24 48 +24 dropbear_mode_cbc 24 48 +24 dropbear_ghash - 24 +24 dropbear_gcm_getlength - 24 +24 gen_new_keys 848 854 +6 ------------------------------------------------------------------------------ (add/remove: 14/0 grow/shrink: 10/0 up/down: 6434/0) Total: 6434 bytes

/* 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"

/**
   @file adler32.c
   Adler-32 checksum algorithm
   Written and placed in the public domain by Wei Dai
   Adapted for libtomcrypt by Steffen Jaeckel
*/
#ifdef LTC_ADLER32

static const unsigned long _adler32_base = 65521;

void adler32_init(adler32_state *ctx)
{
   LTC_ARGCHKVD(ctx != NULL);
   ctx->s[0] = 1;
   ctx->s[1] = 0;
}

void adler32_update(adler32_state *ctx, const unsigned char *input, unsigned long length)
{
   unsigned long s1, s2;

   LTC_ARGCHKVD(ctx != NULL);
   LTC_ARGCHKVD(input != NULL);
   s1 = ctx->s[0];
   s2 = ctx->s[1];

   if (length % 8 != 0) {
      do {
         s1 += *input++;
         s2 += s1;
         length--;
      } while (length % 8 != 0);

      if (s1 >= _adler32_base)
         s1 -= _adler32_base;
      s2 %= _adler32_base;
   }

   while (length > 0) {
      s1 += input[0];
      s2 += s1;
      s1 += input[1];
      s2 += s1;
      s1 += input[2];
      s2 += s1;
      s1 += input[3];
      s2 += s1;
      s1 += input[4];
      s2 += s1;
      s1 += input[5];
      s2 += s1;
      s1 += input[6];
      s2 += s1;
      s1 += input[7];
      s2 += s1;

      length -= 8;
      input += 8;

      if (s1 >= _adler32_base)
         s1 -= _adler32_base;
      s2 %= _adler32_base;
   }

   LTC_ARGCHKVD(s1 < _adler32_base);
   LTC_ARGCHKVD(s2 < _adler32_base);

   ctx->s[0] = (unsigned short)s1;
   ctx->s[1] = (unsigned short)s2;
}

void adler32_finish(adler32_state *ctx, void *hash, unsigned long size)
{
   unsigned char* h;

   LTC_ARGCHKVD(ctx != NULL);
   LTC_ARGCHKVD(hash != NULL);

   h = hash;

   switch (size) {
      default:
         h[3] = ctx->s[0] & 0x0ff;
         /* FALLTHROUGH */
      case 3:
         h[2] = (ctx->s[0] >> 8) & 0x0ff;
         /* FALLTHROUGH */
      case 2:
         h[1] = ctx->s[1] & 0x0ff;
         /* FALLTHROUGH */
      case 1:
         h[0] = (ctx->s[1] >> 8) & 0x0ff;
         /* FALLTHROUGH */
      case 0:
         ;
   }
}

int adler32_test(void)
{
#ifndef LTC_TEST
   return CRYPT_NOP;
#else
   const void* in = "libtomcrypt";
   const unsigned char adler32[] = { 0x1b, 0xe8, 0x04, 0xba };
   unsigned char out[4];
   adler32_state ctx;
   adler32_init(&ctx);
   adler32_update(&ctx, in, strlen(in));
   adler32_finish(&ctx, out, 4);
   if (compare_testvector(adler32, 4, out, 4, "adler32", 0)) {
      return CRYPT_FAIL_TESTVECTOR;
   }
   return CRYPT_OK;
#endif
}
#endif

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */