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

-----BEGIN DSA PRIVATE KEY-----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-----END DSA PRIVATE KEY-----