From 12473d8d4f5f568fa94a4c607a2a04961f8ea618 Mon Sep 17 00:00:00 2001 From: NIIBE Yutaka Date: Wed, 8 Jun 2022 15:22:04 +0900 Subject: [PATCH] Add an AES 256 implementation. Signed-off-by: NIIBE Yutaka --- misc/gen_rijndael_t_table.py | 137 ++++++++++++++++++++ src/Makefile | 9 +- src/aes-t-table.c.in | 66 ++++++++++ src/aes.c | 236 +++++++++++++++++++++++++++++++++++ src/aes.h | 53 ++++++++ 5 files changed, 493 insertions(+), 8 deletions(-) create mode 100644 misc/gen_rijndael_t_table.py create mode 100644 src/aes-t-table.c.in create mode 100644 src/aes.c create mode 100644 src/aes.h diff --git a/misc/gen_rijndael_t_table.py b/misc/gen_rijndael_t_table.py new file mode 100644 index 0000000..7ebc7cd --- /dev/null +++ b/misc/gen_rijndael_t_table.py @@ -0,0 +1,137 @@ +# +# gen_rijndael_t_table.py - Generate Rijndael T-Table +# +# Non-Copyright (CC0) 2020 Free Software Initiative of Japan +# Author: NIIBE Yutaka +# +# This file is made available under the Creative Commons CC0 1.0 +# Universal Public Domain Dedication. +# +# To the extent possible under law, the person who associated CC0 with +# this work has waived all copyright and related or neighboring rights +# to this work. +# + +# +# Generate Rijindael T-Table (the first one) in the format +# of Mbed TLS (originally callled PolarSSL, by Paul Bakker). +# + +# Rijndael uses GF(2^8) with a irreducible polynomial: +# +# m(x) = x^8 + x^4 + x^3 + x + 1 +# +# A point in the field is represented by 8-bit binary. + +# 0x1b represents a lower part of m(x), x^4 + x^3 + x + 1 +m_irreducible = 0x1b + +# The constant +C = 0x63 + +# Function XTIME - Multiplication by x +# +# Given a polynomial A of GF(2)[x], compute a polynomial multiplied by x, +# modulo m(x). +def xtime(a): + global m_irreducible + if a & 0x80: + return ((a & 0x7f) << 1) ^ m_irreducible + else: + return a << 1 + +# Function GMULT - Galore field multiplication +# +# Given polynomials A, B of GF(2)[x], compute a polynomial A * B, +# modulo m(x). +def gmult(a,b): + r = 0 + for i in range(8): + r = r ^ ((b & 0x01) * a) + b = b >> 1 + a = xtime(a) + return r + +# Function INV - Multiplicative inverse +# +# Given polynomials A of GF(2)[x], compute its multiplicative inverse. +# +# Extended to have defined value at A=0, returning 0. +# +# Note about the implementation: +# +# Brute force appoarch finding an inverse is more efficient. Further, +# for efficiency, using two tables of exp and log (with any good base +# like 3, 5, 6...) to compute exp(log(1) - log(a)) is much better, +# when called many times. +# +def inv(a): + r = 1 + for i in range(254): # 254 = 2^8 - 2 + r = gmult(r,a) + return r + +# Circular shift operation +def rotate(a,n): + return ((a << n) & 0xff) | (a >> (8 - n)) + +def rijndael_affine_transform(v): + global C + return v ^ rotate(v,1) ^ rotate(v,2) ^ rotate(v,3) ^ rotate(v,4) ^ C + +def sbox_value(i): + return rijndael_affine_transform(inv(i)) + + +def print_t_table_value(i,x): + y = xtime(x) + z = x ^ y + punct = "" if i==255 else ", \\\n " if i % 4 == 3 else ", " + print("V(","%02X," % z,"%02X," % x,"%02X," % x,"%02X)" % y, + punct, sep='', end='') + +if __name__ == '__main__': + # + # Usage: + # $ python3 gen_rijndael_t_table.py + # + # Usage with args, replacing the irreducible and the constant: + # $ python3 gen_rijndael_t_table.py 1b 63 + # + # Usage to generate Rcon + # $ python3 gen_rijndael_t_table.py 'Rcon[10]' + # + # $ python3 gen_rijndael_t_table.py 1b 63 'Rcon[10]' + # + name_rcon = None + + import sys + if len(sys.argv) == 2: + name_rcon = sys.argv[1] + elif len(sys.argv) >= 3: + m_irreducible = int(sys.argv[1],16) + C = int(sys.argv[2],16) + if len(sys.argv) == 4: + name_rcon = sys.argv[3] + + if name_rcon: + n_rcon = int(name_rcon[name_rcon.index('[')+1:name_rcon.index(']')]) + print("static const uint32_t %s =\n{" % name_rcon) + x = 1 + print(" ", end='') + for i in range(n_rcon): + punct = "\n" if i==n_rcon-1 else ",\n " if i % 4 == 3 else ", " + print("0x%08X" % x, punct, sep='', end='') + x = xtime(x) + print("};") + exit(0) + + # Note: I just want to use list comprehension of Python, though not needed + S_box=[sbox_value(i) for i in range(256)] + + print("#define FT \\") + print(" ", end='') + for i in range(256): + x = S_box[i] + print_t_table_value(i,x) + print("") diff --git a/src/Makefile b/src/Makefile index 08f3c68..fe70631 100644 --- a/src/Makefile +++ b/src/Makefile @@ -8,6 +8,7 @@ CHOPSTX = ../chopstx CSRC = main.c \ usb_desc.c usb_ctrl.c \ usb-ccid.c openpgp.c ac.c openpgp-do.c flash.c \ + aes.c \ bn.c mod.c \ modp256k1.c jpc_p256k1.c ec_p256k1.c call-ec_p256k1.c \ mod25638.c ecc-ed25519.c ecc-mont.c sha512.c \ @@ -17,14 +18,6 @@ CSRC = main.c \ INCDIR = -CRYPTDIR = ../polarssl -CRYPTSRCDIR = $(CRYPTDIR)/library -CRYPTINCDIR = $(CRYPTDIR)/include -CRYPTSRC = $(CRYPTSRCDIR)/aes.c - -CSRC += $(CRYPTSRC) -INCDIR += $(CRYPTINCDIR) - include config.mk USE_SYS = yes diff --git a/src/aes-t-table.c.in b/src/aes-t-table.c.in new file mode 100644 index 0000000..1b54eb4 --- /dev/null +++ b/src/aes-t-table.c.in @@ -0,0 +1,66 @@ +/* Generated by ../misc/gen_rijndael_t_table.py */ +#define FT \ + V(A5,63,63,C6), V(84,7C,7C,F8), V(99,77,77,EE), V(8D,7B,7B,F6), \ + V(0D,F2,F2,FF), V(BD,6B,6B,D6), V(B1,6F,6F,DE), V(54,C5,C5,91), \ + V(50,30,30,60), V(03,01,01,02), V(A9,67,67,CE), V(7D,2B,2B,56), \ + V(19,FE,FE,E7), V(62,D7,D7,B5), V(E6,AB,AB,4D), V(9A,76,76,EC), \ + V(45,CA,CA,8F), V(9D,82,82,1F), V(40,C9,C9,89), V(87,7D,7D,FA), \ + V(15,FA,FA,EF), V(EB,59,59,B2), V(C9,47,47,8E), V(0B,F0,F0,FB), \ + V(EC,AD,AD,41), V(67,D4,D4,B3), V(FD,A2,A2,5F), V(EA,AF,AF,45), \ + V(BF,9C,9C,23), V(F7,A4,A4,53), V(96,72,72,E4), V(5B,C0,C0,9B), \ + V(C2,B7,B7,75), V(1C,FD,FD,E1), V(AE,93,93,3D), V(6A,26,26,4C), \ + V(5A,36,36,6C), V(41,3F,3F,7E), V(02,F7,F7,F5), V(4F,CC,CC,83), \ + V(5C,34,34,68), V(F4,A5,A5,51), V(34,E5,E5,D1), V(08,F1,F1,F9), \ + V(93,71,71,E2), V(73,D8,D8,AB), V(53,31,31,62), V(3F,15,15,2A), \ + V(0C,04,04,08), V(52,C7,C7,95), V(65,23,23,46), V(5E,C3,C3,9D), \ + V(28,18,18,30), V(A1,96,96,37), V(0F,05,05,0A), V(B5,9A,9A,2F), \ + V(09,07,07,0E), V(36,12,12,24), V(9B,80,80,1B), V(3D,E2,E2,DF), \ + V(26,EB,EB,CD), V(69,27,27,4E), V(CD,B2,B2,7F), V(9F,75,75,EA), \ + V(1B,09,09,12), V(9E,83,83,1D), V(74,2C,2C,58), V(2E,1A,1A,34), \ + V(2D,1B,1B,36), V(B2,6E,6E,DC), V(EE,5A,5A,B4), V(FB,A0,A0,5B), \ + V(F6,52,52,A4), V(4D,3B,3B,76), V(61,D6,D6,B7), V(CE,B3,B3,7D), \ + V(7B,29,29,52), V(3E,E3,E3,DD), V(71,2F,2F,5E), V(97,84,84,13), \ + V(F5,53,53,A6), V(68,D1,D1,B9), V(00,00,00,00), V(2C,ED,ED,C1), \ + V(60,20,20,40), V(1F,FC,FC,E3), V(C8,B1,B1,79), V(ED,5B,5B,B6), \ + V(BE,6A,6A,D4), V(46,CB,CB,8D), V(D9,BE,BE,67), V(4B,39,39,72), \ + V(DE,4A,4A,94), V(D4,4C,4C,98), V(E8,58,58,B0), V(4A,CF,CF,85), \ + V(6B,D0,D0,BB), V(2A,EF,EF,C5), V(E5,AA,AA,4F), V(16,FB,FB,ED), \ + V(C5,43,43,86), V(D7,4D,4D,9A), V(55,33,33,66), V(94,85,85,11), \ + V(CF,45,45,8A), V(10,F9,F9,E9), V(06,02,02,04), V(81,7F,7F,FE), \ + V(F0,50,50,A0), V(44,3C,3C,78), V(BA,9F,9F,25), V(E3,A8,A8,4B), \ + V(F3,51,51,A2), V(FE,A3,A3,5D), V(C0,40,40,80), V(8A,8F,8F,05), \ + V(AD,92,92,3F), V(BC,9D,9D,21), V(48,38,38,70), V(04,F5,F5,F1), \ + V(DF,BC,BC,63), V(C1,B6,B6,77), V(75,DA,DA,AF), V(63,21,21,42), \ + V(30,10,10,20), V(1A,FF,FF,E5), V(0E,F3,F3,FD), V(6D,D2,D2,BF), \ + V(4C,CD,CD,81), V(14,0C,0C,18), V(35,13,13,26), V(2F,EC,EC,C3), \ + V(E1,5F,5F,BE), V(A2,97,97,35), V(CC,44,44,88), V(39,17,17,2E), \ + V(57,C4,C4,93), V(F2,A7,A7,55), V(82,7E,7E,FC), V(47,3D,3D,7A), \ + V(AC,64,64,C8), V(E7,5D,5D,BA), V(2B,19,19,32), V(95,73,73,E6), \ + V(A0,60,60,C0), V(98,81,81,19), V(D1,4F,4F,9E), V(7F,DC,DC,A3), \ + V(66,22,22,44), V(7E,2A,2A,54), V(AB,90,90,3B), V(83,88,88,0B), \ + V(CA,46,46,8C), V(29,EE,EE,C7), V(D3,B8,B8,6B), V(3C,14,14,28), \ + V(79,DE,DE,A7), V(E2,5E,5E,BC), V(1D,0B,0B,16), V(76,DB,DB,AD), \ + V(3B,E0,E0,DB), V(56,32,32,64), V(4E,3A,3A,74), V(1E,0A,0A,14), \ + V(DB,49,49,92), V(0A,06,06,0C), V(6C,24,24,48), V(E4,5C,5C,B8), \ + V(5D,C2,C2,9F), V(6E,D3,D3,BD), V(EF,AC,AC,43), V(A6,62,62,C4), \ + V(A8,91,91,39), V(A4,95,95,31), V(37,E4,E4,D3), V(8B,79,79,F2), \ + V(32,E7,E7,D5), V(43,C8,C8,8B), V(59,37,37,6E), V(B7,6D,6D,DA), \ + V(8C,8D,8D,01), V(64,D5,D5,B1), V(D2,4E,4E,9C), V(E0,A9,A9,49), \ + V(B4,6C,6C,D8), V(FA,56,56,AC), V(07,F4,F4,F3), V(25,EA,EA,CF), \ + V(AF,65,65,CA), V(8E,7A,7A,F4), V(E9,AE,AE,47), V(18,08,08,10), \ + V(D5,BA,BA,6F), V(88,78,78,F0), V(6F,25,25,4A), V(72,2E,2E,5C), \ + V(24,1C,1C,38), V(F1,A6,A6,57), V(C7,B4,B4,73), V(51,C6,C6,97), \ + V(23,E8,E8,CB), V(7C,DD,DD,A1), V(9C,74,74,E8), V(21,1F,1F,3E), \ + V(DD,4B,4B,96), V(DC,BD,BD,61), V(86,8B,8B,0D), V(85,8A,8A,0F), \ + V(90,70,70,E0), V(42,3E,3E,7C), V(C4,B5,B5,71), V(AA,66,66,CC), \ + V(D8,48,48,90), V(05,03,03,06), V(01,F6,F6,F7), V(12,0E,0E,1C), \ + V(A3,61,61,C2), V(5F,35,35,6A), V(F9,57,57,AE), V(D0,B9,B9,69), \ + V(91,86,86,17), V(58,C1,C1,99), V(27,1D,1D,3A), V(B9,9E,9E,27), \ + V(38,E1,E1,D9), V(13,F8,F8,EB), V(B3,98,98,2B), V(33,11,11,22), \ + V(BB,69,69,D2), V(70,D9,D9,A9), V(89,8E,8E,07), V(A7,94,94,33), \ + V(B6,9B,9B,2D), V(22,1E,1E,3C), V(92,87,87,15), V(20,E9,E9,C9), \ + V(49,CE,CE,87), V(FF,55,55,AA), V(78,28,28,50), V(7A,DF,DF,A5), \ + V(8F,8C,8C,03), V(F8,A1,A1,59), V(80,89,89,09), V(17,0D,0D,1A), \ + V(DA,BF,BF,65), V(31,E6,E6,D7), V(C6,42,42,84), V(B8,68,68,D0), \ + V(C3,41,41,82), V(B0,99,99,29), V(77,2D,2D,5A), V(11,0F,0F,1E), \ + V(CB,B0,B0,7B), V(FC,54,54,A8), V(D6,BB,BB,6D), V(3A,16,16,2C) diff --git a/src/aes.c b/src/aes.c new file mode 100644 index 0000000..849f41a --- /dev/null +++ b/src/aes.c @@ -0,0 +1,236 @@ +/* + * aes.c - AES256 for Gnuk + * + * Copyright (C) 2020 Free Software Initiative of Japan + * Author: NIIBE Yutaka + * + * This file is a part of Gnuk, a GnuPG USB Token implementation. + * + * Gnuk 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. + * + * Gnuk 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 . + * + * + * This is an implementation using four T tables (little endian), + * keysize fixed for AES-256. + * + */ + +/* + * For AES-256: + * + * Block size in bit = 128, Nb = 4 (= 128 / 32) (in 32-bit word) + * Key size in bit = 256, Nk = 8 (= 256 / 32) (in 32-bit word) + * Number of round Nr = 14 + * + * Contextsize = Nb * (Nr + 1) = 60 (in 32-bit word) + */ +#define Nr 14 +#define Nk (AES_KEY_SIZE/4) + +#include +#include "aes.h" + +static uint32_t +get_uint32_le (const unsigned char *b, unsigned int i) +{ + return ( ((uint32_t)b[i ] ) + | ((uint32_t)b[i + 1] << 8) + | ((uint32_t)b[i + 2] << 16) + | ((uint32_t)b[i + 3] << 24)); +} + +static void +put_uint32_le (unsigned char *b, unsigned int i, uint32_t n) +{ + b[i ] = (unsigned char) ((n) ); + b[i + 1] = (unsigned char) ((n) >> 8); + b[i + 2] = (unsigned char) ((n) >> 16); + b[i + 3] = (unsigned char) ((n) >> 24); +} + + +/* Forward table */ +#include "aes-t-table.c.in" + +#define V(a,b,c,d) 0x##a##b##c##d +/* Note that We expose FT0 table. */ +const uint32_t FT0[256] = { FT }; +#undef V + +#define V(a,b,c,d) 0x##b##c##d##a +static const uint32_t FT1[256] = { FT }; +#undef V + +#define V(a,b,c,d) 0x##c##d##a##b +static const uint32_t FT2[256] = { FT }; +#undef V + +#define V(a,b,c,d) 0x##d##a##b##c +static const uint32_t FT3[256] = { FT }; +#undef V + +#undef FT + +/* Round constants */ +/* + * Note: For AES-256, since (AES_CONTEXT_SIZE / Nk) = 7, we have no + * carry-over in xtime computation for round constants, thus, the + * irreducible polynomial doesn't matter at all. + */ +#define Rcon(i) (1 << i) + + +static void +key_expansion_step_0 (uint32_t *RK, unsigned int i) +{ + RK[8] = RK[0] ^ (FT3[( RK[7] >> 8 ) & 0xff] & 0x000000ff) + ^ (FT0[( RK[7] >> 16 ) & 0Xff] & 0x0000ff00) + ^ (FT1[( RK[7] >> 24 ) & 0Xff] & 0x00ff0000) + ^ (FT2[( RK[7] ) & 0xff] & 0xff000000) + ^ Rcon(i); + RK[9] = RK[1] ^ RK[8]; + RK[10] = RK[2] ^ RK[9]; + RK[11] = RK[3] ^ RK[10]; +} + +static void +key_expansion_step_1 (uint32_t *RK) +{ + RK[12] = RK[4] ^ (FT3[( RK[11] ) & 0xff] & 0x000000ff) + ^ (FT0[( RK[11] >> 8 ) & 0xff] & 0x0000ff00) + ^ (FT1[( RK[11] >> 16 ) & 0xff] & 0x00ff0000) + ^ (FT2[( RK[11] >> 24 ) & 0xff] & 0xff000000); + RK[13] = RK[5] ^ RK[12]; + RK[14] = RK[6] ^ RK[13]; + RK[15] = RK[7] ^ RK[14]; +} + +/* + * AES key setup + */ +void +aes_set_key (aes_context *ctx, const unsigned char key[AES_KEY_SIZE]) +{ + unsigned int i; + uint32_t *RK = ctx->rk; + + /* Nk times */ + RK[0] = get_uint32_le (key, 0); + RK[1] = get_uint32_le (key, 4); + RK[2] = get_uint32_le (key, 8); + RK[3] = get_uint32_le (key, 12); + RK[4] = get_uint32_le (key, 16); + RK[5] = get_uint32_le (key, 20); + RK[6] = get_uint32_le (key, 24); + RK[7] = get_uint32_le (key, 28); + + for (i = 0; i < (AES_CONTEXT_SIZE / Nk) - 1; i++) + { + key_expansion_step_0 (RK, i); + key_expansion_step_1 (RK); + RK += Nk; + } + + key_expansion_step_0 (RK, i); +} + + +static uint32_t +round_calc_step (uint32_t y0, uint32_t y1, uint32_t y2, uint32_t y3) +{ + uint32_t x; + + x = FT0[( y0 ) & 0xff] + ^ FT1[( y1 >> 8 ) & 0xff] + ^ FT2[( y2 >> 16 ) & 0xff] + ^ FT3[( y3 >> 24 ) & 0xff]; + return x; +} + +#define ROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \ + X0 = round_calc_step (Y0, Y1, Y2, Y3) ^ *RK++; \ + X1 = round_calc_step (Y1, Y2, Y3, Y0) ^ *RK++; \ + X2 = round_calc_step (Y2, Y3, Y0, Y1) ^ *RK++; \ + X3 = round_calc_step (Y3, Y0, Y1, Y2) ^ *RK++ + +static uint32_t +last_round_calc_step (uint32_t y0, uint32_t y1, uint32_t y2, uint32_t y3) +{ + uint32_t x; + + x = (FT3[( y0 ) & 0xff] & 0x000000ff) + ^ (FT0[( y1 >> 8 ) & 0xff] & 0x0000ff00) + ^ (FT1[( y2 >> 16 ) & 0xff] & 0x00ff0000) + ^ (FT2[( y3 >> 24 ) & 0xff] & 0xff000000); + return x; +} + +#define LAST_ROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \ + X0 = last_round_calc_step (Y0, Y1, Y2, Y3) ^ *RK++; \ + X1 = last_round_calc_step (Y1, Y2, Y3, Y0) ^ *RK++; \ + X2 = last_round_calc_step (Y2, Y3, Y0, Y1) ^ *RK++; \ + X3 = last_round_calc_step (Y3, Y0, Y1, Y2) ^ *RK++ + +/* + * AES block encryption + */ +void +aes_encrypt (const aes_context *ctx, + unsigned char output[AES_BLOCK_SIZE], + const unsigned char input[AES_BLOCK_SIZE]) +{ + uint32_t X0, X1, X2, X3, Y0, Y1, Y2, Y3; + const uint32_t *RK = ctx->rk; + + /* Nb times */ + X0 = get_uint32_le (input, 0) ^ *RK++; + X1 = get_uint32_le (input, 4) ^ *RK++; + X2 = get_uint32_le (input, 8) ^ *RK++; + X3 = get_uint32_le (input, 12) ^ *RK++; + + /* Nr-1 times */ + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + ROUND (Y0, Y1, Y2, Y3, X0, X1, X2, X3); + + /* And, then */ + LAST_ROUND (X0, X1, X2, X3, Y0, Y1, Y2, Y3); + + /* Nb times */ + put_uint32_le (output, 0, X0); + put_uint32_le (output, 4, X1); + put_uint32_le (output, 8, X2); + put_uint32_le (output, 12, X3); +} + + +/* + * AES key teardown + */ +void +aes_clear_key (aes_context *ctx) +{ + memset (ctx->rk, 0, sizeof ctx->rk); + /* to compiler: no removal of memset above, please */ + asm ("" : : "m" (ctx->rk) : "memory"); +} diff --git a/src/aes.h b/src/aes.h new file mode 100644 index 0000000..dea1dba --- /dev/null +++ b/src/aes.h @@ -0,0 +1,53 @@ +#include + +#define AES_BLOCK_SIZE 16 /* in byte */ + +/* + * For AES-256: + * + * Block size in bit = 128, Nb = 4 (= 128 / 32) (in 32-bit word) + * Key size in bit = 256, Nk = 8 (= 256 / 32) (in 32-bit word) + * Number of round Nr = 14 + * + * Contextsize = Nb * (Nr + 1) = 60 (in 32-bit word) + */ +#define AES_KEY_SIZE 32 /* in byte */ +#define AES_CONTEXT_SIZE 60 /* in word */ + +/** + * AES context structure + * + */ +typedef struct +{ + uint32_t rk[AES_CONTEXT_SIZE]; /*!< AES round keys (60-words) */ +} aes_context; + +/** + * AES key setup + * + * @param ctx AES context + * @param key key + * + */ +void aes_set_key (aes_context *ctx, const unsigned char key[AES_KEY_SIZE]); + +/** + * AES block encryption + * + * @param ctx AES context + * @param output output block + * @param input input block + * + */ +void aes_encrypt (const aes_context *ctx, + unsigned char output[AES_BLOCK_SIZE], + const unsigned char input[AES_BLOCK_SIZE]); + +/** + * AES key teardown + * + * @param ctx AES context + * + */ +void aes_clear_key (aes_context *ctx);