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

/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * SPDX-License-Identifier: Unlicense
 */

/* super class file for PK algos */

/* default ... include all MPI */
#define LTM_ALL

/* RSA only (does not support DH/DSA/ECC) */
/* #define SC_RSA_1 */

/* For reference.... On an Athlon64 optimizing for speed...

   LTM's mpi.o with all functions [striped] is 142KiB in size.

*/

/* Works for RSA only, mpi.o is 68KiB */
#ifdef SC_RSA_1
#   define BN_MP_SHRINK_C
#   define BN_MP_LCM_C
#   define BN_MP_PRIME_RANDOM_EX_C
#   define BN_MP_INVMOD_C
#   define BN_MP_GCD_C
#   define BN_MP_MOD_C
#   define BN_MP_MULMOD_C
#   define BN_MP_ADDMOD_C
#   define BN_MP_EXPTMOD_C
#   define BN_MP_SET_INT_C
#   define BN_MP_INIT_MULTI_C
#   define BN_MP_CLEAR_MULTI_C
#   define BN_MP_UNSIGNED_BIN_SIZE_C
#   define BN_MP_TO_UNSIGNED_BIN_C
#   define BN_MP_MOD_D_C
#   define BN_MP_PRIME_RABIN_MILLER_TRIALS_C
#   define BN_REVERSE_C
#   define BN_PRIME_TAB_C

/* other modifiers */
#   define BN_MP_DIV_SMALL                    /* Slower division, not critical */

/* here we are on the last pass so we turn things off.  The functions classes are still there
 * but we remove them specifically from the build.  This also invokes tweaks in functions
 * like removing support for even moduli, etc...
 */
#   ifdef LTM_LAST
#      undef BN_MP_TOOM_MUL_C
#      undef BN_MP_TOOM_SQR_C
#      undef BN_MP_KARATSUBA_MUL_C
#      undef BN_MP_KARATSUBA_SQR_C
#      undef BN_MP_REDUCE_C
#      undef BN_MP_REDUCE_SETUP_C
#      undef BN_MP_DR_IS_MODULUS_C
#      undef BN_MP_DR_SETUP_C
#      undef BN_MP_DR_REDUCE_C
#      undef BN_MP_REDUCE_IS_2K_C
#      undef BN_MP_REDUCE_2K_SETUP_C
#      undef BN_MP_REDUCE_2K_C
#      undef BN_S_MP_EXPTMOD_C
#      undef BN_MP_DIV_3_C
#      undef BN_S_MP_MUL_HIGH_DIGS_C
#      undef BN_FAST_S_MP_MUL_HIGH_DIGS_C
#      undef BN_FAST_MP_INVMOD_C

/* To safely undefine these you have to make sure your RSA key won't exceed the Comba threshold
 * which is roughly 255 digits [7140 bits for 32-bit machines, 15300 bits for 64-bit machines]
 * which means roughly speaking you can handle upto 2536-bit RSA keys with these defined without
 * trouble.
 */
#      undef BN_S_MP_MUL_DIGS_C
#      undef BN_S_MP_SQR_C
#      undef BN_MP_MONTGOMERY_REDUCE_C
#   endif

#endif

/* ref:         HEAD -> master, tag: v1.1.0 */
/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */