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 der_length_utf8_string.c
  ASN.1 DER, get length of UTF8 STRING, Tom St Denis
*/

#ifdef LTC_DER

/** Return the size in bytes of a UTF-8 character
  @param c   The UTF-8 character to measure
  @return    The size in bytes
*/
unsigned long der_utf8_charsize(const wchar_t c)
{
   if (c <= 0x7F) {
      return 1;
   } else if (c <= 0x7FF) {
      return 2;
#if LTC_WCHAR_MAX == 0xFFFF
   } else {
      return 3;
   }
#else
   } else if (c <= 0xFFFF) {
      return 3;
   } else {
      return 4;
   }
#endif
}

/**
  Test whether the given code point is valid character
  @param c   The UTF-8 character to test
  @return    1 - valid, 0 - invalid
*/
int der_utf8_valid_char(const wchar_t c)
{
   LTC_UNUSED_PARAM(c);
#if !defined(LTC_WCHAR_MAX) || LTC_WCHAR_MAX > 0xFFFF
   if (c > 0x10FFFF) return 0;
#endif
#if LTC_WCHAR_MAX != 0xFFFF && LTC_WCHAR_MAX != 0xFFFFFFFF
   if (c < 0) return 0;
#endif
   return 1;
}

/**
  Gets length of DER encoding of UTF8 STRING
  @param in       The characters to measure the length of
  @param noctets  The number of octets in the string to encode
  @param outlen   [out] The length of the DER encoding for the given string
  @return CRYPT_OK if successful
*/
int der_length_utf8_string(const wchar_t *in, unsigned long noctets, unsigned long *outlen)
{
   unsigned long x, len;

   LTC_ARGCHK(in     != NULL);
   LTC_ARGCHK(outlen != NULL);

   len = 0;
   for (x = 0; x < noctets; x++) {
      if (!der_utf8_valid_char(in[x])) return CRYPT_INVALID_ARG;
      len += der_utf8_charsize(in[x]);
   }

   if (len < 128) {
      /* 0C LL DD DD DD ... */
      *outlen = 2 + len;
   } else if (len < 256) {
      /* 0C 81 LL DD DD DD ... */
      *outlen = 3 + len;
   } else if (len < 65536UL) {
      /* 0C 82 LL LL DD DD DD ... */
      *outlen = 4 + len;
   } else if (len < 16777216UL) {
      /* 0C 83 LL LL LL DD DD DD ... */
      *outlen = 5 + len;
   } else {
      return CRYPT_INVALID_ARG;
   }

   return CRYPT_OK;
}

#endif


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