mirror of https://gerrit.osmocom.org/osmo-tetra
195 lines
11 KiB
C
195 lines
11 KiB
C
/* TETRA HURDLE block cipher implementation */
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/*
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* Copyright (C) 2023 Midnight Blue B.V.
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*
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* Author: Wouter Bokslag <w.bokslag [ ] midnightblue [ ] nl>
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*
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* SPDX-License-Identifier: AGPL-3.0+
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* See the COPYING file in the main directory for details.
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*/
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#include <stdio.h>
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#include <inttypes.h>
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#include <stdlib.h>
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#include "hurdle.h"
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const uint8_t g_abHurdleSbox[256] = {
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0xF4, 0x65, 0x01, 0x00, 0xBA, 0x7A, 0xA7, 0x47, 0x98, 0xDD, 0x9D, 0xAD, 0x96, 0x5D, 0xAA, 0x3D,
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0x58, 0xC0, 0x72, 0xD8, 0x66, 0x4C, 0x3E, 0xE0, 0x80, 0x55, 0xDE, 0x90, 0x2A, 0x4B, 0x83, 0xA0,
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0x51, 0x39, 0xED, 0x6C, 0x8A, 0x2C, 0x56, 0x60, 0x4A, 0x1F, 0xD0, 0x70, 0x6E, 0x33, 0x8B, 0x26,
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0x2E, 0x6F, 0x89, 0x48, 0x5E, 0x40, 0xC3, 0xA4, 0xA9, 0xCF, 0x22, 0x50, 0xE1, 0x15, 0x0C, 0xAB,
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0xD5, 0xF8, 0x5F, 0x36, 0x04, 0xA6, 0x4E, 0x92, 0x1E, 0x2B, 0x88, 0x30, 0x93, 0x45, 0x67, 0x16,
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0x8C, 0x68, 0x23, 0x38, 0x61, 0x25, 0x1A, 0x81, 0x63, 0xCB, 0xC1, 0x13, 0x41, 0x37, 0x0E, 0x97,
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0x5B, 0xCA, 0x57, 0x24, 0x4D, 0x17, 0xC4, 0xB9, 0xB3, 0xEF, 0x8D, 0x52, 0x32, 0x2F, 0xEC, 0x20,
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0xD9, 0x11, 0xD1, 0x28, 0x79, 0xDA, 0xFB, 0xE9, 0xBB, 0x06, 0x77, 0xDB, 0xFC, 0xFE, 0xCD, 0x84,
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0x1D, 0xA1, 0x54, 0x1B, 0xB0, 0xE4, 0xCC, 0x7C, 0x2D, 0x27, 0x31, 0x49, 0xF5, 0x02, 0x69, 0x53,
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0x4F, 0x44, 0xDF, 0x18, 0x5C, 0x0F, 0xBC, 0x9B, 0x94, 0xBD, 0xDC, 0x0B, 0xA2, 0xC7, 0x09, 0xAC,
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0xC6, 0x9F, 0x82, 0x1C, 0x05, 0x46, 0xC2, 0x34, 0x3C, 0x0D, 0x3B, 0xCE, 0xB7, 0xBE, 0x08, 0x9C,
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0x6B, 0xEE, 0xE5, 0x87, 0xAF, 0xBF, 0xF2, 0xEB, 0x7B, 0x07, 0x64, 0xC5, 0xB6, 0xAE, 0x9A, 0x95,
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0x35, 0xA5, 0x59, 0x12, 0x9E, 0xA3, 0xB8, 0x8E, 0x5A, 0xF7, 0x62, 0xD2, 0x3A, 0xA8, 0x7D, 0x85,
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0xF6, 0xC8, 0x71, 0x29, 0xD6, 0xD7, 0x43, 0xF9, 0x78, 0x76, 0x73, 0x10, 0x91, 0x19, 0x0A, 0x99,
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0xF0, 0xE6, 0x3F, 0x14, 0xF1, 0xE2, 0xB1, 0x86, 0xB4, 0xF3, 0x74, 0xFA, 0x6A, 0xB2, 0x21, 0x6D,
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0xEA, 0xB5, 0xE7, 0xE3, 0xC9, 0xD3, 0x8F, 0x03, 0x75, 0xE8, 0xD4, 0x42, 0xFD, 0x7E, 0xFF, 0x7F};
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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static const uint32_t g_adwReorder[16] = {
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0x00000000, 0x80000000, 0x00800000, 0x80800000,
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0x00008000, 0x80008000, 0x00808000, 0x80808000,
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0x00000080, 0x80000080, 0x00800080, 0x80800080,
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0x00008080, 0x80008080, 0x00808080, 0x80808080
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};
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#else
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static const uint32_t g_adwReorder[16] = {
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0x00000000, 0x00000080, 0x00008000, 0x00008080,
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0x00800000, 0x00800080, 0x00808000, 0x00808080,
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0x80000000, 0x80000080, 0x80008000, 0x80008080,
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0x80800000, 0x80800080, 0x80808000, 0x80808080
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};
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#endif
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void hurdle_set_key(uint8_t *k, struct hurdle_ctx *lpContextOut)
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{
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/* Simplified key schedule by precomputing rotates and xor constants */
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uint8_t abKeyBytes[256] = {
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k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15],
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k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4],
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k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9],
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k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14],
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k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3],
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k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6],
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k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13],
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k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2],
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k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7],
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k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12],
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k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1],
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k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8],
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k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11],
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k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0],
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k[6], k[7], k[8], k[9], k[10], k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5],
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k[11], k[12], k[13], k[14], k[15], k[0], k[1], k[2], k[3], k[4], k[5], k[6], k[7], k[8], k[9], k[10]};
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static const uint8_t abKeyXorConsts[256] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x3C, 0xA7, 0xEC, 0x25, 0x79, 0x57, 0xDF, 0xC0, 0x38, 0x0A, 0x33, 0x1E, 0xF3, 0x8C, 0xF4, 0xF7,
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0x6B, 0x78, 0x2C, 0x1D, 0x73, 0x64, 0xC1, 0x33, 0xB4, 0xFE, 0xC4, 0x22, 0x54, 0x60, 0xD1, 0x8E,
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0x58, 0x66, 0xDF, 0x91, 0x87, 0x93, 0xFD, 0x94, 0x58, 0xDB, 0xBD, 0x75, 0x8B, 0xA0, 0xE9, 0x84,
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0xAF, 0x5A, 0x78, 0x7D, 0xA2, 0xEA, 0xAA, 0x4B, 0x98, 0xE3, 0xB7, 0x46, 0x95, 0x53, 0x65, 0x70,
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0x41, 0x05, 0x06, 0x8F, 0x32, 0xCF, 0x3C, 0x77, 0x7E, 0x9F, 0x60, 0x7B, 0x83, 0x23, 0xAE, 0x8F,
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0x4B, 0xD9, 0x73, 0x45, 0x02, 0xD4, 0xFC, 0x6E, 0xB7, 0x4B, 0x36, 0x18, 0x7C, 0xBE, 0x3B, 0xCB,
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0xE8, 0x5B, 0x82, 0x92, 0x32, 0x61, 0xC7, 0xBC, 0x86, 0x31, 0xF8, 0x55, 0x2A, 0xFF, 0xB1, 0xF5,
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0x5D, 0x60, 0x50, 0xA3, 0x48, 0xAF, 0x8A, 0xEA, 0xC7, 0xBB, 0xC6, 0xF6, 0xA8, 0x0E, 0x66, 0xC5,
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0x93, 0x2D, 0x06, 0xE2, 0xC2, 0x91, 0x29, 0x68, 0x36, 0x6C, 0xF6, 0x43, 0x93, 0xDC, 0x57, 0xBF,
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0xAD, 0x8E, 0x84, 0x13, 0x15, 0xA1, 0x9C, 0x53, 0xE4, 0x5D, 0x8C, 0x8D, 0xDE, 0x8A, 0x16, 0x35,
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0x6F, 0x43, 0xB1, 0xA9, 0xF4, 0x89, 0x55, 0xD6, 0x0D, 0xA7, 0xBD, 0x9A, 0xE0, 0x99, 0x55, 0x6B,
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0x95, 0x53, 0x65, 0x70, 0xAF, 0x5A, 0x78, 0x7D, 0xA2, 0xEA, 0xAA, 0x4B, 0x98, 0xE3, 0xB7, 0x46,
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0x66, 0xDF, 0x91, 0x87, 0x93, 0xFD, 0x94, 0x58, 0xDB, 0xBD, 0x75, 0x8B, 0xA0, 0xE9, 0x84, 0x58,
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0xC1, 0x33, 0xB4, 0xFE, 0xC4, 0x22, 0x54, 0x60, 0xD1, 0x8E, 0x6B, 0x78, 0x2C, 0x1D, 0x73, 0x64,
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0x1E, 0xF3, 0x8C, 0xF4, 0xF7, 0x3C, 0xA7, 0xEC, 0x25, 0x79, 0x57, 0xDF, 0xC0, 0x38, 0x0A, 0x33};
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/* Xor original key byte with round- and offset-specific xor byte */
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for (int i = 0; i < 256; i++)
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lpContextOut->abRoundKeys[i] = abKeyBytes[i] ^ abKeyXorConsts[i];
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}
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void HURDLE_f(uint8_t abOutput[4], const uint8_t abRhs[4], const uint8_t *lpRoundKey)
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{
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#define PUSH_OUTPUT_NIBBLE(x) do { \
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dwOutputBits >>= 1; \
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dwOutputBits |= g_adwReorder[(x) & 0xf]; \
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} while (0)
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uint32_t dwOutputBits = 0;
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uint8_t bSboxState = 0;
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bSboxState = g_abHurdleSbox[(abRhs[3] + lpRoundKey[15]) & 0xff];
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bSboxState = g_abHurdleSbox[((abRhs[2] + lpRoundKey[14]) ^ bSboxState) & 0xff];
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bSboxState = g_abHurdleSbox[((abRhs[1] + lpRoundKey[13]) ^ bSboxState) & 0xff];
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bSboxState = g_abHurdleSbox[((abRhs[0] + lpRoundKey[12]) ^ bSboxState) & 0xff];
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bSboxState = g_abHurdleSbox[((abRhs[3] + lpRoundKey[11]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[1] + lpRoundKey[10]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[2] + lpRoundKey[9]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[0] + lpRoundKey[8]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[1] + lpRoundKey[7]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[3] + lpRoundKey[6]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[0] + lpRoundKey[5]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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bSboxState = g_abHurdleSbox[((abRhs[2] + lpRoundKey[4]) ^ bSboxState) & 0xff]; PUSH_OUTPUT_NIBBLE(bSboxState);
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*(uint32_t *)abOutput = dwOutputBits;
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}
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void HURDLE_encrypt(uint8_t abOutput[8], const uint8_t abInput[8], struct hurdle_ctx *lpKey, uint8_t eEncryptMode)
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{
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uint32_t dwLhs, dwRhs, dwTemp;
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int i;
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/* start at first/last round key depending on encrypt/decrypt mode */
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uint8_t *lpRoundKey = (eEncryptMode == HURDLE_DECRYPT) ? &lpKey->abRoundKeys[240] : lpKey->abRoundKeys;
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/* copy state */
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dwLhs = *(uint32_t *)&abInput[0];
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dwRhs = *(uint32_t *)&abInput[4];
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for (i = 0; i < 16; i++) {
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/* Round function */
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HURDLE_f((uint8_t *)&dwTemp, (uint8_t *)&dwRhs, lpRoundKey);
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/* perform a left-right switcharoo */
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dwTemp ^= dwLhs;
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dwLhs = dwRhs;
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dwRhs = dwTemp;
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/* move to next/previous round key depending on encrypt/decrypt mode */
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lpRoundKey += (eEncryptMode == HURDLE_DECRYPT) ? -16 : 16;
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}
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*(uint32_t *)&abOutput[0] = dwRhs;
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*(uint32_t *)&abOutput[4] = dwLhs;
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}
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void HURDLE_enc_cbc(uint8_t abCiphertext[16], const uint8_t abPlaintext[16], uint8_t abKey[16])
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{
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uint8_t abIntermediate[8];
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struct hurdle_ctx stCipher;
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hurdle_set_key(abKey, &stCipher);
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HURDLE_encrypt(abCiphertext, abPlaintext, &stCipher, HURDLE_ENCRYPT);
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*(uint32_t *)&abIntermediate[0] = *(uint32_t *)&abCiphertext[0] ^ *(uint32_t *)&abPlaintext[8];
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*(uint32_t *)&abIntermediate[4] = *(uint32_t *)&abCiphertext[4] ^ *(uint32_t *)&abPlaintext[12];
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HURDLE_encrypt(&abCiphertext[8], abIntermediate, &stCipher, HURDLE_ENCRYPT);
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}
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void HURDLE_dec_cts(uint8_t abPlaintext[15], const uint8_t abCiphertext[15], uint8_t abKey[16])
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{
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uint8_t abIntermediate[16];
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struct hurdle_ctx stCipher;
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hurdle_set_key(abKey, &stCipher);
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HURDLE_encrypt(&abIntermediate[8], &abCiphertext[7], &stCipher, HURDLE_DECRYPT);
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*(uint32_t *)&abIntermediate[0] = *(uint32_t *)&abCiphertext[0];
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*(uint32_t *)&abIntermediate[4] = *(uint32_t *)&abCiphertext[4];
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abIntermediate[7] = abIntermediate[15];
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HURDLE_encrypt(&abIntermediate[0], &abIntermediate[0], &stCipher, HURDLE_DECRYPT);
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*(uint32_t *)&abIntermediate[8] ^= *(uint32_t *)&abCiphertext[0];
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*(uint16_t *)&abIntermediate[12] ^= *(uint16_t *)&abCiphertext[4];
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*(uint8_t *)&abIntermediate[14] ^= *(uint8_t *)&abCiphertext[6];
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*(uint32_t *)&abPlaintext[0] = *(uint32_t *)&abIntermediate[0];
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*(uint32_t *)&abPlaintext[4] = *(uint32_t *)&abIntermediate[4];
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*(uint32_t *)&abPlaintext[8] = *(uint32_t *)&abIntermediate[8];
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*(uint16_t *)&abPlaintext[12] = *(uint16_t *)&abIntermediate[12];
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*(uint8_t *)&abPlaintext[14] = *(uint8_t *)&abIntermediate[14];
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}
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