--- /dev/null
+/* aes_dec-asm.S */
+/*
+ This file is part of the Crypto-avr-lib/microcrypt-lib.
+ Copyright (C) 2008, 2009 Daniel Otte (daniel.otte@rub.de)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * \file aes_dec-asm.S
+ * \email daniel.otte@rub.de
+ * \author Daniel Otte
+ * \date 2009-01-10
+ * \license GPLv3 or later
+ *
+ */
+
+#include "avr-asm-macros.S"
+A = 28
+B = 29
+P = 0
+xREDUCER = 25
+gf256mul:
+ clr P
+1:
+ lsr A
+ breq 4f
+ brcc 2f
+ eor P, B
+2:
+ lsl B
+ brcc 3f
+ eor B, xREDUCER
+3:
+ rjmp 1b
+4:
+ brcc 2f
+ eor P, B
+2:
+ ret
+
+.global aes256_dec
+aes256_dec:
+ ldi r20, 14
+ rjmp aes_decrypt_core
+
+.global aes192_dec
+aes192_dec:
+ ldi r20, 12
+ rjmp aes_decrypt_core
+
+.global aes128_dec
+aes128_dec:
+ ldi r20, 10
+
+
+/*
+ void aes_decrypt_core(aes_cipher_state_t* state, const aes_genctx_t* ks, uint8_t rounds)
+*/
+T0= 2
+T1= 3
+T2= 4
+T3= 5
+T4 = 6
+T5 = 7
+ST00 = 8
+ST01 = 9
+ST02 = 10
+ST03 = 11
+ST10 = 12
+ST11 = 13
+ST12 = 14
+ST13 = 15
+ST20 = 16
+ST21 = 17
+ST22 = 18
+ST23 = 19
+ST30 = 20
+ST31 = 21
+ST32 = 22
+ST33 = 23
+CTR = 24
+/*
+ * param state: r24:r25
+ * param ks: r22:r23
+ * param rounds: r20
+ */
+.global aes_decrypt_core
+aes_decrypt_core:
+ push_range 2, 17
+ push r28
+ push r29
+ push r24
+ push r25
+ movw r26, r22
+ movw r30, r24
+ mov CTR, r20
+ inc r20
+ swap r20 /* r20*16 */
+ add r26, r20
+ adc r27, r1
+ clt
+; ldi CTR, 2
+ .irp param, ST00, ST01, ST02, ST03, ST10, ST11, ST12, ST13, ST20, ST21, ST22, ST23, ST30, ST31, ST32, ST33
+ ld \param, Z+
+ .endr
+
+ ldi xREDUCER, 0x1b /* load reducer */
+ ldi r31, hi8(aes_invsbox)
+
+
+ .irp param, ST33, ST32, ST31, ST30, ST23, ST22, ST21, ST20, ST13, ST12, ST11, ST10, ST03, ST02, ST01, ST00
+ ld r0, -X
+ eor \param, r0
+ .endr
+1:
+ dec CTR
+ brne 2f
+ set
+2:
+ /* substitute and invShift */
+ .irp param, ST00, ST10, ST20, ST30
+ mov r30, \param
+ lpm \param, Z
+ .endr
+ mov r30, ST31
+ lpm T0, Z
+ mov r30, ST21
+ lpm ST31, Z
+ mov r30, ST11
+ lpm ST21, Z
+ mov r30, ST01
+ lpm ST11, Z
+ mov ST01, T0
+
+ mov r30, ST32
+ lpm T0, Z
+ mov r30, ST22
+ lpm T1,Z
+ mov r30, ST12
+ lpm ST32, Z
+ mov r30, ST02
+ lpm ST22, Z
+ mov ST12, T0
+ mov ST02, T1
+
+ mov r30, ST03
+ lpm T0, Z
+ mov r30, ST13
+ lpm ST03, Z
+ mov r30, ST23
+ lpm ST13, Z
+ mov r30, ST33
+ lpm ST23, Z
+ mov ST33, T0
+
+ /* key addition */
+ .irp param, ST33, ST32, ST31, ST30, ST23, ST22, ST21, ST20, ST13, ST12, ST11, ST10, ST03, ST02, ST01, ST00
+ ld r0, -X
+ eor \param, r0
+ .endr
+ brtc 2f
+exit:
+ pop r31
+ pop r30
+ st Z+, ST00
+ st Z+, ST01
+ st Z+, ST02
+ st Z+, ST03
+ st Z+, ST10
+ st Z+, ST11
+ st Z+, ST12
+ st Z+, ST13
+ st Z+, ST20
+ st Z+, ST21
+ st Z+, ST22
+ st Z+, ST23
+ st Z+, ST30
+ st Z+, ST31
+ st Z+, ST32
+ st Z+, ST33
+ pop r29
+ pop r28
+ pop_range 2, 17
+ ret
+2:
+ /* inv column (row) mixing*/
+ /* invMixCol (Row) 1 */
+ /* preparing */
+ mov T0, ST03
+ eor T0, ST02 ; T0 = t
+ mov T1, ST00
+ eor T1, ST01 ; T1 = u
+ mov T2, T0
+ eor T2, T1
+
+ mov B, T2
+ ldi A, 0x08
+ rcall gf256mul
+ eor T2, P ; T2 = v'
+
+ mov B, ST02
+ eor B, ST00
+ ldi A, 0x04
+ rcall gf256mul
+ mov T3, P
+ eor T3, T2; T3 = w
+
+ mov B, ST03
+ eor B, ST01
+ ldi A, 0x04
+ rcall gf256mul
+ eor T2, P ; T2 = v
+
+ /* now the big move */
+ mov T4, ST00
+ eor T4, ST03
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST03, T4
+
+ mov T4, ST02
+ eor T4, ST01
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST01, T4
+
+ lsl T0
+ brcc 3f
+ eor T0, xREDUCER
+3: eor T0, T3
+ eor ST02, T0
+
+ lsl T1
+ brcc 3f
+ eor T1, xREDUCER
+3: eor T1, T3
+ eor ST00, T1
+
+ /* invMixCol (Row) 2 */
+ /* preparing */
+ mov T0, ST13
+ eor T0, ST12 ; T0 = t
+ mov T1, ST10
+ eor T1, ST11 ; T1 = u
+ mov T2, T0
+ eor T2, T1
+
+ mov B, T2
+ ldi A, 0x08
+ rcall gf256mul
+ eor T2, P ; T2 = v'
+
+ mov B, ST12
+ eor B, ST10
+ ldi A, 0x04
+ rcall gf256mul
+ mov T3, P
+ eor T3, T2; T3 = w
+
+ mov B, ST13
+ eor B, ST11
+ ldi A, 0x04
+ rcall gf256mul
+ eor T2, P ; T2 = v
+
+ /* now the big move */
+ mov T4, ST10
+ eor T4, ST13
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST13, T4
+
+ mov T4, ST12
+ eor T4, ST11
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST11, T4
+
+ lsl T0
+ brcc 3f
+ eor T0, xREDUCER
+3: eor T0, T3
+ eor ST12, T0
+
+ lsl T1
+ brcc 3f
+ eor T1, xREDUCER
+3: eor T1, T3
+ eor ST10, T1
+
+ /* invMixCol (Row) 2 */
+ /* preparing */
+ mov T0, ST23
+ eor T0, ST22 ; T0 = t
+ mov T1, ST20
+ eor T1, ST21 ; T1 = u
+ mov T2, T0
+ eor T2, T1
+
+ mov B, T2
+ ldi A, 0x08
+ rcall gf256mul
+ eor T2, P ; T2 = v'
+
+ mov B, ST22
+ eor B, ST20
+ ldi A, 0x04
+ rcall gf256mul
+ mov T3, P
+ eor T3, T2; T3 = w
+
+ mov B, ST23
+ eor B, ST21
+ ldi A, 0x04
+ rcall gf256mul
+ eor T2, P ; T2 = v
+
+ /* now the big move */
+ mov T4, ST20
+ eor T4, ST23
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST23, T4
+
+ mov T4, ST22
+ eor T4, ST21
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST21, T4
+
+ lsl T0
+ brcc 3f
+ eor T0, xREDUCER
+3: eor T0, T3
+ eor ST22, T0
+
+ lsl T1
+ brcc 3f
+ eor T1, xREDUCER
+3: eor T1, T3
+ eor ST20, T1
+
+ /* invMixCol (Row) 3 */
+ /* preparing */
+ mov T0, ST33
+ eor T0, ST32 ; T0 = t
+ mov T1, ST30
+ eor T1, ST31 ; T1 = u
+ mov T2, T0
+ eor T2, T1
+
+ mov B, T2
+ ldi A, 0x08
+ rcall gf256mul
+ eor T2, P ; T2 = v'
+
+ mov B, ST32
+ eor B, ST30
+ ldi A, 0x04
+ rcall gf256mul
+ mov T3, P
+ eor T3, T2; T3 = w
+
+ mov B, ST33
+ eor B, ST31
+ ldi A, 0x04
+ rcall gf256mul
+ eor T2, P ; T2 = v
+
+ /* now the big move */
+ mov T4, ST30
+ eor T4, ST33
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST33, T4
+
+ mov T4, ST32
+ eor T4, ST31
+ lsl T4
+ brcc 3f
+ eor T4, xREDUCER
+3: eor T4, T2
+ eor ST31, T4
+
+ lsl T0
+ brcc 3f
+ eor T0, xREDUCER
+3: eor T0, T3
+ eor ST32, T0
+
+ lsl T1
+ brcc 3f
+ eor T1, xREDUCER
+3: eor T1, T3
+ eor ST30, T1
+
+ rjmp 1b
+
+
+
void aes_dec_round(aes_cipher_state_t* state, const aes_roundkey_t* k){
uint8_t tmp[16];
uint8_t i;
+ uint8_t t,u,v,w;
/* keyAdd */
for(i=0; i<16; ++i){
tmp[i] = state->s[i] ^ k->ks[i];
}
/* mixColums */
for(i=0; i<4; ++i){
+ t = tmp[4*i+3] ^ tmp[4*i+2];
+ u = tmp[4*i+1] ^ tmp[4*i+0];
+ v = t ^ u;
+ v ^= gf256mul(0x08, v, 0x1b);
+ w = v ^ gf256mul(0x04, tmp[4*i+2] ^ tmp[4*i+0], 0x1b);
+ v = v ^ gf256mul(0x04, tmp[4*i+3] ^ tmp[4*i+1], 0x1b);
+ state->s[4*i+3] = tmp[4*i+3] ^ v ^ gf256mul(0x02, tmp[4*i+0] ^ tmp[4*i+3], 0x1b);
+ state->s[4*i+2] = tmp[4*i+2] ^ w ^ gf256mul(0x02, t, 0x1b);
+ state->s[4*i+1] = tmp[4*i+1] ^ v ^ gf256mul(0x02, tmp[4*i+2] ^ tmp[4*i+1], 0x1b);
+ state->s[4*i+0] = tmp[4*i+0] ^ w ^ gf256mul(0x02, u, 0x1b);
+
+ /*
state->s[4*i+0] =
gf256mul(0xe, tmp[4*i+0], 0x1b)
^ gf256mul(0xb, tmp[4*i+1], 0x1b)
^ gf256mul(0xd, tmp[4*i+1], 0x1b)
^ gf256mul(0x9, tmp[4*i+2], 0x1b)
^ gf256mul(0xe, tmp[4*i+3], 0x1b);
+ */
}
/* shiftRows */
aes_invshiftcol(state->s+1, 1);
projects / avr-crypto-lib.git / commitdiff