; Copyright 2015 Egor Tensin ; This file is licensed under the terms of the MIT License. ; See LICENSE.txt for details. .586 .xmm .model flat .code @aesni_aes128_encrypt_block_@20 proc pxor xmm0, [ecx] aesenc xmm0, [ecx + 10h] aesenc xmm0, [ecx + 20h] aesenc xmm0, [ecx + 30h] aesenc xmm0, [ecx + 40h] aesenc xmm0, [ecx + 50h] aesenc xmm0, [ecx + 60h] aesenc xmm0, [ecx + 70h] aesenc xmm0, [ecx + 80h] aesenc xmm0, [ecx + 90h] aesenclast xmm0, [ecx + 0A0h] ret @aesni_aes128_encrypt_block_@20 endp @aesni_aes128_decrypt_block_@20 proc pxor xmm0, [ecx] aesdec xmm0, [ecx + 10h] aesdec xmm0, [ecx + 20h] aesdec xmm0, [ecx + 30h] aesdec xmm0, [ecx + 40h] aesdec xmm0, [ecx + 50h] aesdec xmm0, [ecx + 60h] aesdec xmm0, [ecx + 70h] aesdec xmm0, [ecx + 80h] aesdec xmm0, [ecx + 90h] aesdeclast xmm0, [ecx + 0A0h] ret @aesni_aes128_decrypt_block_@20 endp @aesni_aes128_expand_key_@20 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. ; ; 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: ; * xmm0[127:96] == w[3], ; * xmm0[95:64] == w[2], ; * xmm0[63:32] == w[1], ; * xmm0[31:0] == w[0]. movdqa [ecx], xmm0 ; sets w[0], w[1], w[2], w[3] add ecx, 10h ; ecx = &w[4] aeskeygenassist xmm5, xmm0, 01h ; xmm5[127:96] = RotWord(SubWord(w[3]))^Rcon call aes128_keygen_assist ; sets w[4], w[5], w[6], w[7] aeskeygenassist xmm5, xmm0, 02h ; xmm5[127:96] = RotWord(SubWord(w[7]))^Rcon call aes128_keygen_assist ; sets w[8], w[9], w[10], w[11] aeskeygenassist xmm5, xmm0, 04h ; xmm5[127:96] = RotWord(SubWord(w[11]))^Rcon call aes128_keygen_assist ; sets w[12], w[13], w[14], w[15] aeskeygenassist xmm5, xmm0, 08h ; xmm5[127:96] = RotWord(SubWord(w[15]))^Rcon call aes128_keygen_assist ; sets w[16], w[17], w[18], w[19] aeskeygenassist xmm5, xmm0, 10h ; xmm5[127:96] = RotWord(SubWord(w[19]))^Rcon call aes128_keygen_assist ; sets w[20], w[21], w[22], w[23] aeskeygenassist xmm5, xmm0, 20h ; xmm5[127:96] = RotWord(SubWord(w[23]))^Rcon call aes128_keygen_assist ; sets w[24], w[25], w[26], w[27] aeskeygenassist xmm5, xmm0, 40h ; xmm5[127:96] = RotWord(SubWord(w[27]))^Rcon call aes128_keygen_assist ; sets w[28], w[29], w[30], w[31] aeskeygenassist xmm5, xmm0, 80h ; xmm5[127:96] = RotWord(SubWord(w[31]))^Rcon call aes128_keygen_assist ; sets w[32], w[33], w[34], w[35] aeskeygenassist xmm5, xmm0, 1Bh ; xmm5[127:96] = RotWord(SubWord(w[35]))^Rcon call aes128_keygen_assist ; sets w[36], w[37], w[38], w[39] aeskeygenassist xmm5, xmm0, 36h ; xmm5[127:96] = RotWord(SubWord(w[39]))^Rcon call aes128_keygen_assist ; sets w[40], w[41], w[42], w[43] ret aes128_keygen_assist: ; Preconditions: ; * xmm0[127:96] == w[i+3], ; * xmm0[95:64] == w[i+2], ; * xmm0[63:32] == w[i+1], ; * xmm0[31:0] == w[i], ; * xmm5[127:96] == RotWord(SubWord(w[i+3]))^Rcon, ; * ecx == &w[i+4]. ; ; Postconditions: ; * xmm0[127:96] == w[i+7] == RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i], ; * xmm0[95:64] == w[i+6] == RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i], ; * xmm0[63:32] == w[i+5] == RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i], ; * xmm0[31:0] == w[i+4] == RotWord(SubWord(w[i+3]))^Rcon^w[i], ; * ecx == &w[i+8], ; * the value in xmm4 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 xmm4, xmm0 ; xmm4 = xmm0 pslldq xmm4, 4 ; xmm4 <<= 32 pxor xmm0, xmm4 ; xmm0 ^= xmm4 pslldq xmm4, 4 ; xmm4 <<= 32 pxor xmm0, xmm4 ; xmm0 ^= xmm4 pslldq xmm4, 4 ; xmm4 <<= 32 pxor xmm0, xmm4 ; xmm0 ^= xmm4 ; xmm0[127:96] == w[i+3]^w[i+2]^w[i+1]^w[i] ; xmm0[95:64] == w[i+2]^w[i+1]^w[i] ; xmm0[63:32] == w[i+1]^w[i] ; xmm0[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 xmm4, xmm5, 0FFh ; xmm4[127:96] = xmm4[95:64] = xmm4[63:32] = xmm4[31:0] = xmm5[127:96] pxor xmm0, xmm4 ; xmm0 ^= xmm4 ; xmm0[127:96] == w[i+7] == RotWord(SubWord(w[i+3]))^Rcon^w[i+3]^w[i+2]^w[i+1]^w[i] ; xmm0[95:64] == w[i+6] == RotWord(SubWord(w[i+3]))^Rcon^w[i+2]^w[i+1]^w[i] ; xmm0[63:32] == w[i+5] == RotWord(SubWord(w[i+3]))^Rcon^w[i+1]^w[i] ; xmm0[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], xmm0 ; 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 @aesni_aes128_expand_key_@20 endp @aesni_aes128_derive_decryption_keys_raw@8 proc movdqa xmm5, [ecx] movdqa xmm4, [ecx + 0A0h] movdqa [edx], xmm4 movdqa [edx + 0A0h], xmm5 aesimc xmm5, [ecx + 10h] aesimc xmm4, [ecx + 90h] movdqa [edx + 10h], xmm4 movdqa [edx + 90h], xmm5 aesimc xmm5, [ecx + 20h] aesimc xmm4, [ecx + 80h] movdqa [edx + 20h], xmm4 movdqa [edx + 80h], xmm5 aesimc xmm5, [ecx + 30h] aesimc xmm4, [ecx + 70h] movdqa [edx + 30h], xmm4 movdqa [edx + 70h], xmm5 aesimc xmm5, [ecx + 40h] aesimc xmm4, [ecx + 60h] movdqa [edx + 40h], xmm4 movdqa [edx + 60h], xmm5 aesimc xmm5, [ecx + 50h] movdqa [edx + 50h], xmm5 ret @aesni_aes128_derive_decryption_keys_raw@8 endp end