879 lines
20 KiB
C
879 lines
20 KiB
C
/* $OpenBSD: aes.c,v 1.2 2020/07/22 13:54:30 tobhe Exp $ */
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/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Modified for OpenBSD by Thomas Pornin and Mike Belopuhov.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <sys/types.h>
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#include <sys/systm.h>
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#include <sys/stdint.h>
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#include "aes.h"
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static inline void
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enc32le(void *dst, uint32_t x)
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{
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unsigned char *buf = dst;
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buf[0] = (unsigned char)x;
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buf[1] = (unsigned char)(x >> 8);
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buf[2] = (unsigned char)(x >> 16);
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buf[3] = (unsigned char)(x >> 24);
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}
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static inline uint32_t
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dec32le(const void *src)
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{
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const unsigned char *buf = src;
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return (uint32_t)buf[0]
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| ((uint32_t)buf[1] << 8)
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| ((uint32_t)buf[2] << 16)
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| ((uint32_t)buf[3] << 24);
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}
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/*
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* This constant-time implementation is "bitsliced": the 128-bit state is
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* split over eight 32-bit words q* in the following way:
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*
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* -- Input block consists in 16 bytes:
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* a00 a10 a20 a30 a01 a11 a21 a31 a02 a12 a22 a32 a03 a13 a23 a33
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* In the terminology of FIPS 197, this is a 4x4 matrix which is read
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* column by column.
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*
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* -- Each byte is split into eight bits which are distributed over the
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* eight words, at the same rank. Thus, for a byte x at rank k, bit 0
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* (least significant) of x will be at rank k in q0 (if that bit is b,
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* then it contributes "b << k" to the value of q0), bit 1 of x will be
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* at rank k in q1, and so on.
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*
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* -- Ranks given to bits are in "row order" and are either all even, or
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* all odd. Two independent AES states are thus interleaved, one using
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* the even ranks, the other the odd ranks. Row order means:
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* a00 a01 a02 a03 a10 a11 a12 a13 a20 a21 a22 a23 a30 a31 a32 a33
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*
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* Converting input bytes from two AES blocks to bitslice representation
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* is done in the following way:
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* -- Decode first block into the four words q0 q2 q4 q6, in that order,
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* using little-endian convention.
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* -- Decode second block into the four words q1 q3 q5 q7, in that order,
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* using little-endian convention.
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* -- Call aes_ct_ortho().
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*
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* Converting back to bytes is done by using the reverse operations. Note
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* that aes_ct_ortho() is its own inverse.
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*/
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/*
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* The AES S-box, as a bitsliced constant-time version. The input array
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* consists in eight 32-bit words; 32 S-box instances are computed in
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* parallel. Bits 0 to 7 of each S-box input (bit 0 is least significant)
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* are spread over the words 0 to 7, at the same rank.
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*/
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static void
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aes_ct_bitslice_Sbox(uint32_t *q)
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{
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/*
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* This S-box implementation is a straightforward translation of
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* the circuit described by Boyar and Peralta in "A new
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* combinational logic minimization technique with applications
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* to cryptology" (https://eprint.iacr.org/2009/191.pdf).
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*
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* Note that variables x* (input) and s* (output) are numbered
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* in "reverse" order (x0 is the high bit, x7 is the low bit).
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*/
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uint32_t x0, x1, x2, x3, x4, x5, x6, x7;
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uint32_t y1, y2, y3, y4, y5, y6, y7, y8, y9;
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uint32_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19;
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uint32_t y20, y21;
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uint32_t z0, z1, z2, z3, z4, z5, z6, z7, z8, z9;
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uint32_t z10, z11, z12, z13, z14, z15, z16, z17;
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uint32_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9;
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uint32_t t10, t11, t12, t13, t14, t15, t16, t17, t18, t19;
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uint32_t t20, t21, t22, t23, t24, t25, t26, t27, t28, t29;
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uint32_t t30, t31, t32, t33, t34, t35, t36, t37, t38, t39;
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uint32_t t40, t41, t42, t43, t44, t45, t46, t47, t48, t49;
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uint32_t t50, t51, t52, t53, t54, t55, t56, t57, t58, t59;
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uint32_t t60, t61, t62, t63, t64, t65, t66, t67;
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uint32_t s0, s1, s2, s3, s4, s5, s6, s7;
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x0 = q[7];
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x1 = q[6];
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x2 = q[5];
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x3 = q[4];
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x4 = q[3];
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x5 = q[2];
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x6 = q[1];
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x7 = q[0];
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/*
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* Top linear transformation.
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*/
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y14 = x3 ^ x5;
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y13 = x0 ^ x6;
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y9 = x0 ^ x3;
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y8 = x0 ^ x5;
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t0 = x1 ^ x2;
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y1 = t0 ^ x7;
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y4 = y1 ^ x3;
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y12 = y13 ^ y14;
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y2 = y1 ^ x0;
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y5 = y1 ^ x6;
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y3 = y5 ^ y8;
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t1 = x4 ^ y12;
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y15 = t1 ^ x5;
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y20 = t1 ^ x1;
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y6 = y15 ^ x7;
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y10 = y15 ^ t0;
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y11 = y20 ^ y9;
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y7 = x7 ^ y11;
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y17 = y10 ^ y11;
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y19 = y10 ^ y8;
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y16 = t0 ^ y11;
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y21 = y13 ^ y16;
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y18 = x0 ^ y16;
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/*
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* Non-linear section.
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*/
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t2 = y12 & y15;
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t3 = y3 & y6;
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t4 = t3 ^ t2;
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t5 = y4 & x7;
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t6 = t5 ^ t2;
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t7 = y13 & y16;
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t8 = y5 & y1;
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t9 = t8 ^ t7;
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t10 = y2 & y7;
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t11 = t10 ^ t7;
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t12 = y9 & y11;
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t13 = y14 & y17;
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t14 = t13 ^ t12;
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t15 = y8 & y10;
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t16 = t15 ^ t12;
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t17 = t4 ^ t14;
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t18 = t6 ^ t16;
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t19 = t9 ^ t14;
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t20 = t11 ^ t16;
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t21 = t17 ^ y20;
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t22 = t18 ^ y19;
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t23 = t19 ^ y21;
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t24 = t20 ^ y18;
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t25 = t21 ^ t22;
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t26 = t21 & t23;
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t27 = t24 ^ t26;
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t28 = t25 & t27;
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t29 = t28 ^ t22;
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t30 = t23 ^ t24;
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t31 = t22 ^ t26;
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t32 = t31 & t30;
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t33 = t32 ^ t24;
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t34 = t23 ^ t33;
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t35 = t27 ^ t33;
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t36 = t24 & t35;
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t37 = t36 ^ t34;
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t38 = t27 ^ t36;
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t39 = t29 & t38;
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t40 = t25 ^ t39;
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t41 = t40 ^ t37;
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t42 = t29 ^ t33;
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t43 = t29 ^ t40;
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t44 = t33 ^ t37;
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t45 = t42 ^ t41;
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z0 = t44 & y15;
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z1 = t37 & y6;
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z2 = t33 & x7;
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z3 = t43 & y16;
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z4 = t40 & y1;
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z5 = t29 & y7;
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z6 = t42 & y11;
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z7 = t45 & y17;
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z8 = t41 & y10;
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z9 = t44 & y12;
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z10 = t37 & y3;
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z11 = t33 & y4;
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z12 = t43 & y13;
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z13 = t40 & y5;
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z14 = t29 & y2;
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z15 = t42 & y9;
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z16 = t45 & y14;
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z17 = t41 & y8;
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/*
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* Bottom linear transformation.
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*/
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t46 = z15 ^ z16;
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t47 = z10 ^ z11;
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t48 = z5 ^ z13;
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t49 = z9 ^ z10;
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t50 = z2 ^ z12;
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t51 = z2 ^ z5;
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t52 = z7 ^ z8;
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t53 = z0 ^ z3;
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t54 = z6 ^ z7;
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t55 = z16 ^ z17;
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t56 = z12 ^ t48;
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t57 = t50 ^ t53;
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t58 = z4 ^ t46;
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t59 = z3 ^ t54;
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t60 = t46 ^ t57;
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t61 = z14 ^ t57;
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t62 = t52 ^ t58;
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t63 = t49 ^ t58;
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t64 = z4 ^ t59;
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t65 = t61 ^ t62;
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t66 = z1 ^ t63;
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s0 = t59 ^ t63;
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s6 = t56 ^ ~t62;
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s7 = t48 ^ ~t60;
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t67 = t64 ^ t65;
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s3 = t53 ^ t66;
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s4 = t51 ^ t66;
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s5 = t47 ^ t65;
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s1 = t64 ^ ~s3;
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s2 = t55 ^ ~t67;
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q[7] = s0;
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q[6] = s1;
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q[5] = s2;
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q[4] = s3;
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q[3] = s4;
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q[2] = s5;
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q[1] = s6;
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q[0] = s7;
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}
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/*
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* Perform bytewise orthogonalization of eight 32-bit words. Bytes
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* of q0..q7 are spread over all words: for a byte x that occurs
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* at rank i in q[j] (byte x uses bits 8*i to 8*i+7 in q[j]), the bit
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* of rank k in x (0 <= k <= 7) goes to q[k] at rank 8*i+j.
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*
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* This operation is an involution.
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*/
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static void
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aes_ct_ortho(uint32_t *q)
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{
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#define SWAPN(cl, ch, s, x, y) do { \
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uint32_t a, b; \
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a = (x); \
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b = (y); \
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(x) = (a & (uint32_t)cl) | ((b & (uint32_t)cl) << (s)); \
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(y) = ((a & (uint32_t)ch) >> (s)) | (b & (uint32_t)ch); \
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} while (0)
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#define SWAP2(x, y) SWAPN(0x55555555, 0xAAAAAAAA, 1, x, y)
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#define SWAP4(x, y) SWAPN(0x33333333, 0xCCCCCCCC, 2, x, y)
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#define SWAP8(x, y) SWAPN(0x0F0F0F0F, 0xF0F0F0F0, 4, x, y)
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SWAP2(q[0], q[1]);
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SWAP2(q[2], q[3]);
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SWAP2(q[4], q[5]);
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SWAP2(q[6], q[7]);
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SWAP4(q[0], q[2]);
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SWAP4(q[1], q[3]);
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SWAP4(q[4], q[6]);
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SWAP4(q[5], q[7]);
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SWAP8(q[0], q[4]);
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SWAP8(q[1], q[5]);
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SWAP8(q[2], q[6]);
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SWAP8(q[3], q[7]);
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}
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static inline uint32_t
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sub_word(uint32_t x)
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{
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uint32_t q[8];
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int i;
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for (i = 0; i < 8; i ++) {
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q[i] = x;
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}
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aes_ct_ortho(q);
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aes_ct_bitslice_Sbox(q);
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aes_ct_ortho(q);
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return q[0];
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}
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static const unsigned char Rcon[] = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36
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};
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/*
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* Base key schedule code. The function sub_word() must be defined
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* below. Subkeys are produced in little-endian convention (but not
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* bitsliced). Key length is expressed in bytes.
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*/
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static unsigned
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aes_keysched_base(uint32_t *skey, const void *key, size_t key_len)
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{
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unsigned num_rounds;
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int i, j, k, nk, nkf;
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uint32_t tmp;
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switch (key_len) {
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case 16:
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num_rounds = 10;
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break;
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case 24:
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num_rounds = 12;
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break;
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case 32:
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num_rounds = 14;
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break;
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default:
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return 0;
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}
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nk = (int)(key_len >> 2);
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nkf = (int)((num_rounds + 1) << 2);
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for (i = 0; i < nk; i ++) {
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tmp = dec32le((const unsigned char *)key + (i << 2));
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skey[i] = tmp;
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}
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tmp = skey[(key_len >> 2) - 1];
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for (i = nk, j = 0, k = 0; i < nkf; i ++) {
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if (j == 0) {
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tmp = (tmp << 24) | (tmp >> 8);
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tmp = sub_word(tmp) ^ Rcon[k];
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} else if (nk > 6 && j == 4) {
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tmp = sub_word(tmp);
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}
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tmp ^= skey[i - nk];
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skey[i] = tmp;
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if (++ j == nk) {
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j = 0;
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k ++;
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}
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}
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return num_rounds;
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}
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/*
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* AES key schedule, constant-time version. skey[] is filled with n+1
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* 128-bit subkeys, where n is the number of rounds (10 to 14, depending
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* on key size). The number of rounds is returned. If the key size is
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* invalid (not 16, 24 or 32), then 0 is returned.
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*/
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unsigned
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aes_ct_keysched(uint32_t *comp_skey, const void *key, size_t key_len)
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{
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uint32_t skey[60];
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unsigned u, num_rounds;
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num_rounds = aes_keysched_base(skey, key, key_len);
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for (u = 0; u <= num_rounds; u ++) {
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uint32_t q[8];
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q[0] = q[1] = skey[(u << 2) + 0];
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q[2] = q[3] = skey[(u << 2) + 1];
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q[4] = q[5] = skey[(u << 2) + 2];
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q[6] = q[7] = skey[(u << 2) + 3];
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aes_ct_ortho(q);
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comp_skey[(u << 2) + 0] =
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(q[0] & 0x55555555) | (q[1] & 0xAAAAAAAA);
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comp_skey[(u << 2) + 1] =
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(q[2] & 0x55555555) | (q[3] & 0xAAAAAAAA);
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comp_skey[(u << 2) + 2] =
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(q[4] & 0x55555555) | (q[5] & 0xAAAAAAAA);
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comp_skey[(u << 2) + 3] =
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(q[6] & 0x55555555) | (q[7] & 0xAAAAAAAA);
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}
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return num_rounds;
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}
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/*
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* Expand AES subkeys as produced by aes_ct_keysched(), into
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* a larger array suitable for aes_ct_bitslice_encrypt() and
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* aes_ct_bitslice_decrypt().
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*/
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void
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aes_ct_skey_expand(uint32_t *skey,
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unsigned num_rounds, const uint32_t *comp_skey)
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{
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unsigned u, v, n;
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n = (num_rounds + 1) << 2;
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for (u = 0, v = 0; u < n; u ++, v += 2) {
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uint32_t x, y;
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x = y = comp_skey[u];
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x &= 0x55555555;
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skey[v + 0] = x | (x << 1);
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y &= 0xAAAAAAAA;
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skey[v + 1] = y | (y >> 1);
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}
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}
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static inline void
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add_round_key(uint32_t *q, const uint32_t *sk)
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{
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q[0] ^= sk[0];
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q[1] ^= sk[1];
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q[2] ^= sk[2];
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q[3] ^= sk[3];
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q[4] ^= sk[4];
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q[5] ^= sk[5];
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q[6] ^= sk[6];
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q[7] ^= sk[7];
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}
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static inline void
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shift_rows(uint32_t *q)
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{
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int i;
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for (i = 0; i < 8; i ++) {
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uint32_t x;
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x = q[i];
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q[i] = (x & 0x000000FF)
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| ((x & 0x0000FC00) >> 2) | ((x & 0x00000300) << 6)
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| ((x & 0x00F00000) >> 4) | ((x & 0x000F0000) << 4)
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| ((x & 0xC0000000) >> 6) | ((x & 0x3F000000) << 2);
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}
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}
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static inline uint32_t
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rotr16(uint32_t x)
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{
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return (x << 16) | (x >> 16);
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}
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|
|
|
static inline void
|
|
mix_columns(uint32_t *q)
|
|
{
|
|
uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
|
|
uint32_t r0, r1, r2, r3, r4, r5, r6, r7;
|
|
|
|
q0 = q[0];
|
|
q1 = q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = q[5];
|
|
q6 = q[6];
|
|
q7 = q[7];
|
|
r0 = (q0 >> 8) | (q0 << 24);
|
|
r1 = (q1 >> 8) | (q1 << 24);
|
|
r2 = (q2 >> 8) | (q2 << 24);
|
|
r3 = (q3 >> 8) | (q3 << 24);
|
|
r4 = (q4 >> 8) | (q4 << 24);
|
|
r5 = (q5 >> 8) | (q5 << 24);
|
|
r6 = (q6 >> 8) | (q6 << 24);
|
|
r7 = (q7 >> 8) | (q7 << 24);
|
|
|
|
q[0] = q7 ^ r7 ^ r0 ^ rotr16(q0 ^ r0);
|
|
q[1] = q0 ^ r0 ^ q7 ^ r7 ^ r1 ^ rotr16(q1 ^ r1);
|
|
q[2] = q1 ^ r1 ^ r2 ^ rotr16(q2 ^ r2);
|
|
q[3] = q2 ^ r2 ^ q7 ^ r7 ^ r3 ^ rotr16(q3 ^ r3);
|
|
q[4] = q3 ^ r3 ^ q7 ^ r7 ^ r4 ^ rotr16(q4 ^ r4);
|
|
q[5] = q4 ^ r4 ^ r5 ^ rotr16(q5 ^ r5);
|
|
q[6] = q5 ^ r5 ^ r6 ^ rotr16(q6 ^ r6);
|
|
q[7] = q6 ^ r6 ^ r7 ^ rotr16(q7 ^ r7);
|
|
}
|
|
|
|
/*
|
|
* Compute AES encryption on bitsliced data. Since input is stored on
|
|
* eight 32-bit words, two block encryptions are actually performed
|
|
* in parallel.
|
|
*/
|
|
void
|
|
aes_ct_bitslice_encrypt(unsigned num_rounds,
|
|
const uint32_t *skey, uint32_t *q)
|
|
{
|
|
unsigned u;
|
|
|
|
add_round_key(q, skey);
|
|
for (u = 1; u < num_rounds; u ++) {
|
|
aes_ct_bitslice_Sbox(q);
|
|
shift_rows(q);
|
|
mix_columns(q);
|
|
add_round_key(q, skey + (u << 3));
|
|
}
|
|
aes_ct_bitslice_Sbox(q);
|
|
shift_rows(q);
|
|
add_round_key(q, skey + (num_rounds << 3));
|
|
}
|
|
|
|
/*
|
|
* Like aes_ct_bitslice_Sbox(), but for the inverse S-box.
|
|
*/
|
|
void
|
|
aes_ct_bitslice_invSbox(uint32_t *q)
|
|
{
|
|
/*
|
|
* AES S-box is:
|
|
* S(x) = A(I(x)) ^ 0x63
|
|
* where I() is inversion in GF(256), and A() is a linear
|
|
* transform (0 is formally defined to be its own inverse).
|
|
* Since inversion is an involution, the inverse S-box can be
|
|
* computed from the S-box as:
|
|
* iS(x) = B(S(B(x ^ 0x63)) ^ 0x63)
|
|
* where B() is the inverse of A(). Indeed, for any y in GF(256):
|
|
* iS(S(y)) = B(A(I(B(A(I(y)) ^ 0x63 ^ 0x63))) ^ 0x63 ^ 0x63) = y
|
|
*
|
|
* Note: we reuse the implementation of the forward S-box,
|
|
* instead of duplicating it here, so that total code size is
|
|
* lower. By merging the B() transforms into the S-box circuit
|
|
* we could make faster CBC decryption, but CBC decryption is
|
|
* already quite faster than CBC encryption because we can
|
|
* process two blocks in parallel.
|
|
*/
|
|
uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
|
|
|
|
q0 = ~q[0];
|
|
q1 = ~q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = ~q[5];
|
|
q6 = ~q[6];
|
|
q7 = q[7];
|
|
q[7] = q1 ^ q4 ^ q6;
|
|
q[6] = q0 ^ q3 ^ q5;
|
|
q[5] = q7 ^ q2 ^ q4;
|
|
q[4] = q6 ^ q1 ^ q3;
|
|
q[3] = q5 ^ q0 ^ q2;
|
|
q[2] = q4 ^ q7 ^ q1;
|
|
q[1] = q3 ^ q6 ^ q0;
|
|
q[0] = q2 ^ q5 ^ q7;
|
|
|
|
aes_ct_bitslice_Sbox(q);
|
|
|
|
q0 = ~q[0];
|
|
q1 = ~q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = ~q[5];
|
|
q6 = ~q[6];
|
|
q7 = q[7];
|
|
q[7] = q1 ^ q4 ^ q6;
|
|
q[6] = q0 ^ q3 ^ q5;
|
|
q[5] = q7 ^ q2 ^ q4;
|
|
q[4] = q6 ^ q1 ^ q3;
|
|
q[3] = q5 ^ q0 ^ q2;
|
|
q[2] = q4 ^ q7 ^ q1;
|
|
q[1] = q3 ^ q6 ^ q0;
|
|
q[0] = q2 ^ q5 ^ q7;
|
|
}
|
|
|
|
static inline void
|
|
inv_shift_rows(uint32_t *q)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i ++) {
|
|
uint32_t x;
|
|
|
|
x = q[i];
|
|
q[i] = (x & 0x000000FF)
|
|
| ((x & 0x00003F00) << 2) | ((x & 0x0000C000) >> 6)
|
|
| ((x & 0x000F0000) << 4) | ((x & 0x00F00000) >> 4)
|
|
| ((x & 0x03000000) << 6) | ((x & 0xFC000000) >> 2);
|
|
}
|
|
}
|
|
|
|
static void
|
|
inv_mix_columns(uint32_t *q)
|
|
{
|
|
uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
|
|
uint32_t r0, r1, r2, r3, r4, r5, r6, r7;
|
|
|
|
q0 = q[0];
|
|
q1 = q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = q[5];
|
|
q6 = q[6];
|
|
q7 = q[7];
|
|
r0 = (q0 >> 8) | (q0 << 24);
|
|
r1 = (q1 >> 8) | (q1 << 24);
|
|
r2 = (q2 >> 8) | (q2 << 24);
|
|
r3 = (q3 >> 8) | (q3 << 24);
|
|
r4 = (q4 >> 8) | (q4 << 24);
|
|
r5 = (q5 >> 8) | (q5 << 24);
|
|
r6 = (q6 >> 8) | (q6 << 24);
|
|
r7 = (q7 >> 8) | (q7 << 24);
|
|
|
|
q[0] = q5 ^ q6 ^ q7 ^ r0 ^ r5 ^ r7 ^ rotr16(q0 ^ q5 ^ q6 ^ r0 ^ r5);
|
|
q[1] = q0 ^ q5 ^ r0 ^ r1 ^ r5 ^ r6 ^ r7 ^ rotr16(q1 ^ q5 ^ q7 ^ r1 ^ r5 ^ r6);
|
|
q[2] = q0 ^ q1 ^ q6 ^ r1 ^ r2 ^ r6 ^ r7 ^ rotr16(q0 ^ q2 ^ q6 ^ r2 ^ r6 ^ r7);
|
|
q[3] = q0 ^ q1 ^ q2 ^ q5 ^ q6 ^ r0 ^ r2 ^ r3 ^ r5 ^ rotr16(q0 ^ q1 ^ q3 ^ q5 ^ q6 ^ q7 ^ r0 ^ r3 ^ r5 ^ r7);
|
|
q[4] = q1 ^ q2 ^ q3 ^ q5 ^ r1 ^ r3 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr16(q1 ^ q2 ^ q4 ^ q5 ^ q7 ^ r1 ^ r4 ^ r5 ^ r6);
|
|
q[5] = q2 ^ q3 ^ q4 ^ q6 ^ r2 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr16(q2 ^ q3 ^ q5 ^ q6 ^ r2 ^ r5 ^ r6 ^ r7);
|
|
q[6] = q3 ^ q4 ^ q5 ^ q7 ^ r3 ^ r5 ^ r6 ^ r7 ^ rotr16(q3 ^ q4 ^ q6 ^ q7 ^ r3 ^ r6 ^ r7);
|
|
q[7] = q4 ^ q5 ^ q6 ^ r4 ^ r6 ^ r7 ^ rotr16(q4 ^ q5 ^ q7 ^ r4 ^ r7);
|
|
}
|
|
|
|
/*
|
|
* Compute AES decryption on bitsliced data. Since input is stored on
|
|
* eight 32-bit words, two block decryptions are actually performed
|
|
* in parallel.
|
|
*/
|
|
void
|
|
aes_ct_bitslice_decrypt(unsigned num_rounds,
|
|
const uint32_t *skey, uint32_t *q)
|
|
{
|
|
unsigned u;
|
|
|
|
add_round_key(q, skey + (num_rounds << 3));
|
|
for (u = num_rounds - 1; u > 0; u --) {
|
|
inv_shift_rows(q);
|
|
aes_ct_bitslice_invSbox(q);
|
|
add_round_key(q, skey + (u << 3));
|
|
inv_mix_columns(q);
|
|
}
|
|
inv_shift_rows(q);
|
|
aes_ct_bitslice_invSbox(q);
|
|
add_round_key(q, skey);
|
|
}
|
|
|
|
|
|
int
|
|
AES_Setkey(AES_CTX *ctx, const uint8_t *key, int len)
|
|
{
|
|
ctx->num_rounds = aes_ct_keysched(ctx->sk, key, len);
|
|
if (ctx->num_rounds == 0)
|
|
return -1;
|
|
aes_ct_skey_expand(ctx->sk_exp, ctx->num_rounds, ctx->sk);
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
AES_Encrypt_ECB(AES_CTX *ctx, const uint8_t *src,
|
|
uint8_t *dst, size_t num_blocks)
|
|
{
|
|
while (num_blocks > 0) {
|
|
uint32_t q[8];
|
|
|
|
q[0] = dec32le(src);
|
|
q[2] = dec32le(src + 4);
|
|
q[4] = dec32le(src + 8);
|
|
q[6] = dec32le(src + 12);
|
|
if (num_blocks > 1) {
|
|
q[1] = dec32le(src + 16);
|
|
q[3] = dec32le(src + 20);
|
|
q[5] = dec32le(src + 24);
|
|
q[7] = dec32le(src + 28);
|
|
} else {
|
|
q[1] = 0;
|
|
q[3] = 0;
|
|
q[5] = 0;
|
|
q[7] = 0;
|
|
}
|
|
aes_ct_ortho(q);
|
|
aes_ct_bitslice_encrypt(ctx->num_rounds, ctx->sk_exp, q);
|
|
aes_ct_ortho(q);
|
|
enc32le(dst, q[0]);
|
|
enc32le(dst + 4, q[2]);
|
|
enc32le(dst + 8, q[4]);
|
|
enc32le(dst + 12, q[6]);
|
|
if (num_blocks > 1) {
|
|
enc32le(dst + 16, q[1]);
|
|
enc32le(dst + 20, q[3]);
|
|
enc32le(dst + 24, q[5]);
|
|
enc32le(dst + 28, q[7]);
|
|
src += 32;
|
|
dst += 32;
|
|
num_blocks -= 2;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
AES_Decrypt_ECB(AES_CTX *ctx, const uint8_t *src,
|
|
uint8_t *dst, size_t num_blocks)
|
|
{
|
|
while (num_blocks > 0) {
|
|
uint32_t q[8];
|
|
|
|
q[0] = dec32le(src);
|
|
q[2] = dec32le(src + 4);
|
|
q[4] = dec32le(src + 8);
|
|
q[6] = dec32le(src + 12);
|
|
if (num_blocks > 1) {
|
|
q[1] = dec32le(src + 16);
|
|
q[3] = dec32le(src + 20);
|
|
q[5] = dec32le(src + 24);
|
|
q[7] = dec32le(src + 28);
|
|
} else {
|
|
q[1] = 0;
|
|
q[3] = 0;
|
|
q[5] = 0;
|
|
q[7] = 0;
|
|
}
|
|
aes_ct_ortho(q);
|
|
aes_ct_bitslice_decrypt(ctx->num_rounds, ctx->sk_exp, q);
|
|
aes_ct_ortho(q);
|
|
enc32le(dst, q[0]);
|
|
enc32le(dst + 4, q[2]);
|
|
enc32le(dst + 8, q[4]);
|
|
enc32le(dst + 12, q[6]);
|
|
if (num_blocks > 1) {
|
|
enc32le(dst + 16, q[1]);
|
|
enc32le(dst + 20, q[3]);
|
|
enc32le(dst + 24, q[5]);
|
|
enc32le(dst + 28, q[7]);
|
|
src += 32;
|
|
dst += 32;
|
|
num_blocks -= 2;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
AES_Encrypt(AES_CTX *ctx, const uint8_t *src, uint8_t *dst)
|
|
{
|
|
AES_Encrypt_ECB(ctx, src, dst, 1);
|
|
}
|
|
|
|
void
|
|
AES_Decrypt(AES_CTX *ctx, const uint8_t *src, uint8_t *dst)
|
|
{
|
|
AES_Decrypt_ECB(ctx, src, dst, 1);
|
|
}
|
|
|
|
int
|
|
AES_KeySetup_Encrypt(uint32_t *skey, const uint8_t *key, int len)
|
|
{
|
|
unsigned r, u;
|
|
uint32_t tkey[60];
|
|
|
|
r = aes_keysched_base(tkey, key, len);
|
|
if (r == 0) {
|
|
return 0;
|
|
}
|
|
for (u = 0; u < ((r + 1) << 2); u ++) {
|
|
uint32_t w;
|
|
|
|
w = tkey[u];
|
|
skey[u] = (w << 24)
|
|
| ((w & 0x0000FF00) << 8)
|
|
| ((w & 0x00FF0000) >> 8)
|
|
| (w >> 24);
|
|
}
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Reduce value x modulo polynomial x^8+x^4+x^3+x+1. This works as
|
|
* long as x fits on 12 bits at most.
|
|
*/
|
|
static inline uint32_t
|
|
redgf256(uint32_t x)
|
|
{
|
|
uint32_t h;
|
|
|
|
h = x >> 8;
|
|
return (x ^ h ^ (h << 1) ^ (h << 3) ^ (h << 4)) & 0xFF;
|
|
}
|
|
|
|
/*
|
|
* Multiplication by 0x09 in GF(256).
|
|
*/
|
|
static inline uint32_t
|
|
mul9(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 3));
|
|
}
|
|
|
|
/*
|
|
* Multiplication by 0x0B in GF(256).
|
|
*/
|
|
static inline uint32_t
|
|
mulb(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 1) ^ (x << 3));
|
|
}
|
|
|
|
/*
|
|
* Multiplication by 0x0D in GF(256).
|
|
*/
|
|
static inline uint32_t
|
|
muld(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 2) ^ (x << 3));
|
|
}
|
|
|
|
/*
|
|
* Multiplication by 0x0E in GF(256).
|
|
*/
|
|
static inline uint32_t
|
|
mule(uint32_t x)
|
|
{
|
|
return redgf256((x << 1) ^ (x << 2) ^ (x << 3));
|
|
}
|
|
|
|
int
|
|
AES_KeySetup_Decrypt(uint32_t *skey, const uint8_t *key, int len)
|
|
{
|
|
unsigned r, u;
|
|
uint32_t tkey[60];
|
|
|
|
/*
|
|
* Compute encryption subkeys. We get them in big-endian
|
|
* notation.
|
|
*/
|
|
r = AES_KeySetup_Encrypt(tkey, key, len);
|
|
if (r == 0) {
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Copy the subkeys in reverse order. Also, apply InvMixColumns()
|
|
* on the subkeys (except first and last).
|
|
*/
|
|
memcpy(skey + (r << 2), tkey, 4 * sizeof(uint32_t));
|
|
memcpy(skey, tkey + (r << 2), 4 * sizeof(uint32_t));
|
|
for (u = 4; u < (r << 2); u ++) {
|
|
uint32_t sk, sk0, sk1, sk2, sk3;
|
|
uint32_t tk, tk0, tk1, tk2, tk3;
|
|
|
|
sk = tkey[u];
|
|
sk0 = sk >> 24;
|
|
sk1 = (sk >> 16) & 0xFF;
|
|
sk2 = (sk >> 8) & 0xFF;
|
|
sk3 = sk & 0xFF;
|
|
tk0 = mule(sk0) ^ mulb(sk1) ^ muld(sk2) ^ mul9(sk3);
|
|
tk1 = mul9(sk0) ^ mule(sk1) ^ mulb(sk2) ^ muld(sk3);
|
|
tk2 = muld(sk0) ^ mul9(sk1) ^ mule(sk2) ^ mulb(sk3);
|
|
tk3 = mulb(sk0) ^ muld(sk1) ^ mul9(sk2) ^ mule(sk3);
|
|
tk = (tk0 << 24) ^ (tk1 << 16) ^ (tk2 << 8) ^ tk3;
|
|
skey[((r - (u >> 2)) << 2) + (u & 3)] = tk;
|
|
}
|
|
|
|
return r;
|
|
}
|