/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/**
@file multi2.c
Multi-2 implementation (not public domain, hence the default disable)
*/
#include "tomcrypt_private.h"
#ifdef LTC_MULTI2
static void s_pi1(ulong32 *p)
{
p[1] ^= p[0];
}
static void s_pi2(ulong32 *p, const ulong32 *k)
{
ulong32 t;
t = (p[1] + k[0]) & 0xFFFFFFFFUL;
t = (ROL(t, 1) + t - 1) & 0xFFFFFFFFUL;
t = (ROL(t, 4) ^ t) & 0xFFFFFFFFUL;
p[0] ^= t;
}
static void s_pi3(ulong32 *p, const ulong32 *k)
{
ulong32 t;
t = p[0] + k[1];
t = (ROL(t, 2) + t + 1) & 0xFFFFFFFFUL;
t = (ROL(t, 8) ^ t) & 0xFFFFFFFFUL;
t = (t + k[2]) & 0xFFFFFFFFUL;
t = (ROL(t, 1) - t) & 0xFFFFFFFFUL;
t = ROL(t, 16) ^ (p[0] | t);
p[1] ^= t;
}
static void s_pi4(ulong32 *p, const ulong32 *k)
{
ulong32 t;
t = (p[1] + k[3]) & 0xFFFFFFFFUL;
t = (ROL(t, 2) + t + 1) & 0xFFFFFFFFUL;
p[0] ^= t;
}
static void s_setup(const ulong32 *dk, const ulong32 *k, ulong32 *uk)
{
int n, t;
ulong32 p[2];
p[0] = dk[0]; p[1] = dk[1];
t = 4;
n = 0;
s_pi1(p);
s_pi2(p, k);
uk[n++] = p[0];
s_pi3(p, k);
uk[n++] = p[1];
s_pi4(p, k);
uk[n++] = p[0];
s_pi1(p);
uk[n++] = p[1];
s_pi2(p, k+t);
uk[n++] = p[0];
s_pi3(p, k+t);
uk[n++] = p[1];
s_pi4(p, k+t);
uk[n++] = p[0];
s_pi1(p);
uk[n++] = p[1];
}
static void s_encrypt(ulong32 *p, int N, const ulong32 *uk)
{
int n, t;
for (t = n = 0; ; ) {
s_pi1(p); if (++n == N) break;
s_pi2(p, uk+t); if (++n == N) break;
s_pi3(p, uk+t); if (++n == N) break;
s_pi4(p, uk+t); if (++n == N) break;
t ^= 4;
}
}
static void s_decrypt(ulong32 *p, int N, const ulong32 *uk)
{
int n, t;
for (t = 4*(((N-1)>>2)&1), n = N; ; ) {
switch (n<=4 ? n : ((n-1)%4)+1) {
case 4: s_pi4(p, uk+t); --n; /* FALLTHROUGH */
case 3: s_pi3(p, uk+t); --n; /* FALLTHROUGH */
case 2: s_pi2(p, uk+t); --n; /* FALLTHROUGH */
case 1: s_pi1(p); --n; break;
case 0: return;
}
t ^= 4;
}
}
const struct ltc_cipher_descriptor multi2_desc = {
"multi2",
22,
40, 40, 8, 128,
&multi2_setup,
&multi2_ecb_encrypt,
&multi2_ecb_decrypt,
&multi2_test,
&multi2_done,
&multi2_keysize,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};
int multi2_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
ulong32 sk[8], dk[2];
int x;
LTC_ARGCHK(key != NULL);
LTC_ARGCHK(skey != NULL);
if (keylen != 40) return CRYPT_INVALID_KEYSIZE;
if (num_rounds == 0) num_rounds = 128;
skey->multi2.N = num_rounds;
for (x = 0; x < 8; x++) {
LOAD32H(sk[x], key + x*4);
}
LOAD32H(dk[0], key + 32);
LOAD32H(dk[1], key + 36);
s_setup(dk, sk, skey->multi2.uk);
zeromem(sk, sizeof(sk));
zeromem(dk, sizeof(dk));
return CRYPT_OK;
}
/**
Encrypts a block of text with multi2
@param pt The input plaintext (8 bytes)
@param ct The output ciphertext (8 bytes)
@param skey The key as scheduled
@return CRYPT_OK if successful
*/
int multi2_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
{
ulong32 p[2];
LTC_ARGCHK(pt != NULL);
LTC_ARGCHK(ct != NULL);
LTC_ARGCHK(skey != NULL);
LOAD32H(p[0], pt);
LOAD32H(p[1], pt+4);
s_encrypt(p, skey->multi2.N, skey->multi2.uk);
STORE32H(p[0], ct);
STORE32H(p[1], ct+4);
return CRYPT_OK;
}
/**
Decrypts a block of text with multi2
@param ct The input ciphertext (8 bytes)
@param pt The output plaintext (8 bytes)
@param skey The key as scheduled
@return CRYPT_OK if successful
*/
int multi2_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
{
ulong32 p[2];
LTC_ARGCHK(pt != NULL);
LTC_ARGCHK(ct != NULL);
LTC_ARGCHK(skey != NULL);
LOAD32H(p[0], ct);
LOAD32H(p[1], ct+4);
s_decrypt(p, skey->multi2.N, skey->multi2.uk);
STORE32H(p[0], pt);
STORE32H(p[1], pt+4);
return CRYPT_OK;
}
/**
Performs a self-test of the multi2 block cipher
@return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
*/
int multi2_test(void)
{
static const struct {
unsigned char key[40];
unsigned char pt[8], ct[8];
int rounds;
} tests[] = {
{
{
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x01, 0x23, 0x45, 0x67,
0x89, 0xAB, 0xCD, 0xEF
},
{
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x01,
},
{
0xf8, 0x94, 0x40, 0x84,
0x5e, 0x11, 0xcf, 0x89
},
128,
},
{
{
0x35, 0x91, 0x9d, 0x96,
0x07, 0x02, 0xe2, 0xce,
0x8d, 0x0b, 0x58, 0x3c,
0xc9, 0xc8, 0x9d, 0x59,
0xa2, 0xae, 0x96, 0x4e,
0x87, 0x82, 0x45, 0xed,
0x3f, 0x2e, 0x62, 0xd6,
0x36, 0x35, 0xd0, 0x67,
0xb1, 0x27, 0xb9, 0x06,
0xe7, 0x56, 0x22, 0x38,
},
{
0x1f, 0xb4, 0x60, 0x60,
0xd0, 0xb3, 0x4f, 0xa5
},
{
0xca, 0x84, 0xa9, 0x34,
0x75, 0xc8, 0x60, 0xe5
},
216,
}
};
unsigned char buf[8];
symmetric_key skey;
int err, x;
for (x = 1; x < (int)(sizeof(tests)/sizeof(tests[0])); x++) {
if ((err = multi2_setup(tests[x].key, 40, tests[x].rounds, &skey)) != CRYPT_OK) {
return err;
}
if ((err = multi2_ecb_encrypt(tests[x].pt, buf, &skey)) != CRYPT_OK) {
return err;
}
if (compare_testvector(buf, 8, tests[x].ct, 8, "Multi2 Encrypt", x)) {
return CRYPT_FAIL_TESTVECTOR;
}
if ((err = multi2_ecb_decrypt(buf, buf, &skey)) != CRYPT_OK) {
return err;
}
if (compare_testvector(buf, 8, tests[x].pt, 8, "Multi2 Decrypt", x)) {
return CRYPT_FAIL_TESTVECTOR;
}
}
for (x = 128; x < 256; ++x) {
unsigned char ct[8];
if ((err = multi2_setup(tests[0].key, 40, x, &skey)) != CRYPT_OK) {
return err;
}
if ((err = multi2_ecb_encrypt(tests[0].pt, ct, &skey)) != CRYPT_OK) {
return err;
}
if ((err = multi2_ecb_decrypt(ct, buf, &skey)) != CRYPT_OK) {
return err;
}
if (compare_testvector(buf, 8, tests[0].pt, 8, "Multi2 Rounds", x)) {
return CRYPT_FAIL_TESTVECTOR;
}
}
return CRYPT_OK;
}
/** Terminate the context
@param skey The scheduled key
*/
void multi2_done(symmetric_key *skey)
{
LTC_UNUSED_PARAM(skey);
}
/**
Gets suitable key size
@param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
@return CRYPT_OK if the input key size is acceptable.
*/
int multi2_keysize(int *keysize)
{
LTC_ARGCHK(keysize != NULL);
if (*keysize >= 40) {
*keysize = 40;
} else {
return CRYPT_INVALID_KEYSIZE;
}
return CRYPT_OK;
}
#endif