; Copyright 2015 Egor Tensin ; This file is licensed under the terms of the MIT License. ; See LICENSE.txt for details. .586 .xmm .model flat .data align 10h key_schedule oword 11 dup(0) align 10h inverted_key_schedule oword 11 dup(0) .code @raw_aes128ecb_encrypt@32 proc call expand_keys128 pxor xmm0, [key_schedule] aesenc xmm0, [key_schedule + 10h] aesenc xmm0, [key_schedule + 20h] aesenc xmm0, [key_schedule + 30h] aesenc xmm0, [key_schedule + 40h] aesenc xmm0, [key_schedule + 50h] aesenc xmm0, [key_schedule + 60h] aesenc xmm0, [key_schedule + 70h] aesenc xmm0, [key_schedule + 80h] aesenc xmm0, [key_schedule + 90h] aesenclast xmm0, [key_schedule + 0A0h] ret @raw_aes128ecb_encrypt@32 endp @raw_aes128cbc_encrypt@36 proc pxor xmm0, [ecx] jmp @raw_aes128ecb_encrypt@32 @raw_aes128cbc_encrypt@36 endp @raw_aes128ecb_decrypt@32 proc call expand_keys128 pxor xmm0, [inverted_key_schedule] aesdec xmm0, [inverted_key_schedule + 10h] aesdec xmm0, [inverted_key_schedule + 20h] aesdec xmm0, [inverted_key_schedule + 30h] aesdec xmm0, [inverted_key_schedule + 40h] aesdec xmm0, [inverted_key_schedule + 50h] aesdec xmm0, [inverted_key_schedule + 60h] aesdec xmm0, [inverted_key_schedule + 70h] aesdec xmm0, [inverted_key_schedule + 80h] aesdec xmm0, [inverted_key_schedule + 90h] aesdeclast xmm0, [inverted_key_schedule + 0A0h] ret @raw_aes128ecb_decrypt@32 endp @raw_aes128cbc_decrypt@36 proc push ecx call @raw_aes128ecb_decrypt@32 pop ecx pxor xmm0, [ecx] ret @raw_aes128cbc_decrypt@36 endp expand_keys128 proc ; A "word" (in terms of the FIPS 187 standard) is a 32-bit block. ; Words are denoted by `w[N]`. ; ; A key schedule is composed of 10 "regular" keys and a dumb key for ; the "whitening" step. ; It's stored in `key_schedule`. ; ; A key schedule is thus composed of 44 "words". ; The FIPS standard includes an algorithm to calculate these words via ; a simple loop: ; ; i = 4 ; while i < 44: ; temp = w[i - 1] ; if i % 4 == 0: ; temp = SubWord(RotWord(temp))^Rcon ; w[i] = w[i - 4]^temp ; i = i + 1 ; ; The loop above may be unrolled like this: ; ; w[4] = SubWord(RotWord(w[3]))^Rcon^w[0] ; w[5] = w[4]^w[1] ; = SubWord(RotWord(w[3]))^Rcon^w[1]^w[0] ; w[6] = w[5]^w[2] ; = SubWord(RotWord(w[3]))^Rcon^w[2]^w[1]^w[0] ; w[7] = w[6]^w[3] ; = SubWord(RotWord(w[3]))^Rcon^w[3]^w[2]^w[1]^w[0] ; w[8] = SubWord(RotWord(w[7]))^Rcon^w[4] ; w[9] = w[8]^w[5] ; = SubWord(RotWord(w[7]))^Rcon^w[5]^w[4] ; w[10] = w[9]^w[6] ; = SubWord(RotWord(w[7]))^Rcon^w[6]^w[5]^w[4] ; w[11] = w[10]^w[7] ; = SubWord(RotWord(w[7]))^Rcon^w[7]^w[6]^w[5]^w[4] ; ; ... and so on. ; ; The Intel AES-NI instruction set facilitates calculating SubWord ; and RotWord using `aeskeygenassist`, which is used in this routine. ; ; Preconditions: ; * xmm1[127:96] == w[3], ; * xmm1[95:64] == w[2], ; * xmm1[63:32] == w[1], ; * xmm1[31:0] == w[0]. movdqa [key_schedule], xmm1 ; sets w[0], w[1], w[2], w[3] lea ecx, [key_schedule + 10h] ; ecx = &w[4] aeskeygenassist xmm7, xmm1, 01h ; xmm7[127:96] = RotWord(SubWord(w[3]))^Rcon call gen_round_key ; sets w[4], w[5], w[6], w[7] aeskeygenassist xmm7, xmm1, 02h ; xmm7[127:96] = RotWord(SubWord(w[7]))^Rcon call gen_round_key ; sets w[8], w[9], w[10], w[11] aeskeygenassist xmm7, xmm1, 04h ; xmm7[127:96] = RotWord(SubWord(w[11]))^Rcon call gen_round_key ; sets w[12], w[13], w[14], w[15] aeskeygenassist xmm7, xmm1, 08h ; xmm7[127:96] = RotWord(SubWord(w[15]))^Rcon call gen_round_key ; sets w[16], w[17], w[18], w[19] aeskeygenassist xmm7, xmm1, 10h ; xmm7[127:96] = RotWord(SubWord(w[19]))^Rcon call gen_round_key ; sets w[20], w[21], w[22], w[23] aeskeygenassist xmm7, xmm1, 20h ; xmm7[127:96] = RotWord(SubWord(w[23]))^Rcon call gen_round_key ; sets w[24], w[25], w[26], w[27] aeskeygenassist xmm7, xmm1, 40h ; xmm7[127:96] = RotWord(SubWord(w[27]))^Rcon call gen_round_key ; sets w[28], w[29], w[30], w[31] aeskeygenassist xmm7, xmm1, 80h ; xmm7[127:96] = RotWord(SubWord(w[31]))^Rcon call gen_round_key ; sets w[32], w[33], w[34], w[35] aeskeygenassist xmm7, xmm1, 1Bh ; xmm7[127:96] = RotWord(SubWord(w[35]))^Rcon call gen_round_key ; sets w[36], w[37], w[38], w[39] aeskeygenassist xmm7, xmm1, 36h ; xmm7[127:96] = RotWord(SubWord(w[39]))^Rcon call gen_round_key ; sets w[40], w[41], w[42], w[43] call invert_key_schedule ret gen_round_key: ; Preconditions: ; * xmm1[127:96] == w[i+3], ; * xmm1[95:64] == w[i+2], ; * xmm1[63:32] == w[i+1], ; * xmm1[31:0] == w[i], ; * xmm7[127:96] == RotWord(SubWord(w[i+3]))^Rcon, ; * ecx == &w[i+4]. ; ; Postconditions: ; * xmm1[127:96] == w[i+7] == RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i], ; * xmm1[95:64] == w[i+6] == RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i], ; * xmm1[63:32] == w[i+5] == RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i], ; * xmm1[31:0] == w[i+4] == RotWord(SubWord(w[i+3]))^Rcon^w[i], ; * ecx == &w[i+8], ; * the value in xmm6 is also modified. ; Calculate ; w[i+3]^w[i+2]^w[i+1]^w[i], ; w[i+2]^w[i+1]^w[i], ; w[i+1]^w[i] and ; w[i]. movdqa xmm6, xmm1 ; xmm6 = xmm1 pslldq xmm6, 4 ; xmm6 <<= 32 pxor xmm1, xmm6 ; xmm1 ^= xmm6 pslldq xmm6, 4 ; xmm6 <<= 32 pxor xmm1, xmm6 ; xmm1 ^= xmm6 pslldq xmm6, 4 ; xmm6 <<= 32 pxor xmm1, xmm6 ; xmm1 ^= xmm6 ; xmm1[127:96] == w[i+3]^w[i+2]^w[i+1]^w[i] ; xmm1[95:64] == w[i+2]^w[i+1]^w[i] ; xmm1[63:32] == w[i+1]^w[i] ; xmm1[31:0] == w[i] ; Calculate ; w[i+7] == RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i], ; w[i+6] == RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i], ; w[i+5] == RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i] and ; w[i+4] == RotWord(SubWord(w[i+3]))^Rcon^w[i]. pshufd xmm6, xmm7, 0FFh ; xmm6[127:96] = xmm6[95:64] = xmm6[63:32] = xmm6[31:0] = xmm7[127:96] pxor xmm1, xmm6 ; xmm1 ^= xmm6 ; xmm1[127:96] == w[i+7] == RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i] ; xmm1[95:64] == w[i+6] == RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i] ; xmm1[63:32] == w[i+5] == RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i] ; xmm1[31:0] == w[i+4] == RotWord(SubWord(w[i+3]))^Rcon^w[i] ; Set w[i+4], w[i+5], w[i+6] and w[i+7]. movdqa [ecx], xmm1 ; w[i+7] = RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i] ; w[i+6] = RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i] ; w[i+5] = RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i] ; w[i+4] = RotWord(SubWord(w[i+3]))^Rcon^w[i] add ecx, 10h ; ecx = &w[i+8] ret invert_key_schedule: movdqa xmm7, [key_schedule] movdqa xmm6, [key_schedule + 0A0h] movdqa [inverted_key_schedule], xmm6 movdqa [inverted_key_schedule + 0A0h], xmm7 aesimc xmm7, [key_schedule + 10h] aesimc xmm6, [key_schedule + 90h] movdqa [inverted_key_schedule + 10h], xmm6 movdqa [inverted_key_schedule + 90h], xmm7 aesimc xmm7, [key_schedule + 20h] aesimc xmm6, [key_schedule + 80h] movdqa [inverted_key_schedule + 20h], xmm6 movdqa [inverted_key_schedule + 80h], xmm7 aesimc xmm7, [key_schedule + 30h] aesimc xmm6, [key_schedule + 70h] movdqa [inverted_key_schedule + 30h], xmm6 movdqa [inverted_key_schedule + 70h], xmm7 aesimc xmm7, [key_schedule + 40h] aesimc xmm6, [key_schedule + 60h] movdqa [inverted_key_schedule + 40h], xmm6 movdqa [inverted_key_schedule + 60h], xmm7 aesimc xmm7, [key_schedule + 50h] movdqa [inverted_key_schedule + 50h], xmm7 ret expand_keys128 endp end