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.
 */

/* The implementation is based on:
 * Public Domain poly1305 from Andrew Moon
 * https://github.com/floodyberry/poly1305-donna
 */

#include "tomcrypt.h"

#ifdef LTC_POLY1305

int poly1305_test(void)
{
#ifndef LTC_TEST
   return CRYPT_NOP;
#else
   /* https://tools.ietf.org/html/rfc7539#section-2.5.2 */
   unsigned char k[]   = { 0x85, 0xd6, 0xbe, 0x78, 0x57, 0x55, 0x6d, 0x33, 0x7f, 0x44, 0x52, 0xfe, 0x42, 0xd5, 0x06, 0xa8, 0x01, 0x03, 0x80, 0x8a, 0xfb, 0x0d, 0xb2, 0xfd, 0x4a, 0xbf, 0xf6, 0xaf, 0x41, 0x49, 0xf5, 0x1b };
   unsigned char tag[] = { 0xA8, 0x06, 0x1D, 0xC1, 0x30, 0x51, 0x36, 0xC6, 0xC2, 0x2B, 0x8B, 0xAF, 0x0C, 0x01, 0x27, 0xA9 };
   char m[] = "Cryptographic Forum Research Group";
   unsigned long len = 16, mlen = strlen(m);
   unsigned char out[1000];
   poly1305_state st;
   int err;

   /* process piece by piece */
   if ((err = poly1305_init(&st, k, 32)) != CRYPT_OK)                                return err;
   if ((err = poly1305_process(&st, (unsigned char*)m,      5)) != CRYPT_OK)         return err;
   if ((err = poly1305_process(&st, (unsigned char*)m + 5,  4)) != CRYPT_OK)         return err;
   if ((err = poly1305_process(&st, (unsigned char*)m + 9,  3)) != CRYPT_OK)         return err;
   if ((err = poly1305_process(&st, (unsigned char*)m + 12, 2)) != CRYPT_OK)         return err;
   if ((err = poly1305_process(&st, (unsigned char*)m + 14, 1)) != CRYPT_OK)         return err;
   if ((err = poly1305_process(&st, (unsigned char*)m + 15, mlen - 15)) != CRYPT_OK) return err;
   if ((err = poly1305_done(&st, out, &len)) != CRYPT_OK)                            return err;
   if (compare_testvector(out, len, tag, sizeof(tag), "POLY1305-TV1", 1) != 0)       return CRYPT_FAIL_TESTVECTOR;
   /* process in one go */
   if ((err = poly1305_init(&st, k, 32)) != CRYPT_OK)                                return err;
   if ((err = poly1305_process(&st, (unsigned char*)m, mlen)) != CRYPT_OK)           return err;
   if ((err = poly1305_done(&st, out, &len)) != CRYPT_OK)                            return err;
   if (compare_testvector(out, len, tag, sizeof(tag), "POLY1305-TV2", 1) != 0)       return CRYPT_FAIL_TESTVECTOR;
   return CRYPT_OK;
#endif
}

#endif

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