/*
* TEE_BigIntMulMod
*/
void TEE_BigIntMulMod(TEE_BigInt *dest, const TEE_BigInt *op1,
const TEE_BigInt *op2, const TEE_BigInt *n)
{
mpanum mpa_dest = (mpa_num_base *)dest;
mpanum mpa_op1 = (mpa_num_base *)op1;
mpanum mpa_op2 = (mpa_num_base *)op2;
mpanum mpa_n = (mpa_num_base *)n;
mpanum tmp_dest;
if (TEE_BigIntCmpS32(n, 2) < 0)
TEE_BigInt_Panic("Modulus is too short");
/*
* From the spec, mpa_dest must be of magnitude "mpa_n"
* But internal computations in mpa do not have such assumptions
* (as __mpa_div_q_r, where "r" must be of magnitude "op1",
* whereas GP provides a magnitude of "op2")
* This is a tempory variable is used, before storing the
* final result.
*/
mpa_alloc_static_temp_var(&tmp_dest, mempool);
mpa_mul_mod(tmp_dest, mpa_op1, mpa_op2, mpa_n, mempool);
if (mpa_cmp_short(tmp_dest, 0) < 0)
mpa_add(tmp_dest, tmp_dest, mpa_n, mempool);
mpa_copy(mpa_dest, tmp_dest);
mpa_free_static_temp_var(&tmp_dest, mempool);
}
/* add */
static int add(void *a, void *b, void *c)
{
LTC_ARGCHK(a != NULL);
LTC_ARGCHK(b != NULL);
LTC_ARGCHK(c != NULL);
mpa_add((mpanum) c, (const mpanum) a, (const mpanum) b, external_mem_pool);
return CRYPT_OK;
}
/*
* TEE_BigIntAdd
*/
void TEE_BigIntAdd(TEE_BigInt *dest, const TEE_BigInt *op1,
const TEE_BigInt *op2)
{
mpanum mpa_dest = (mpa_num_base *)dest;
mpanum mpa_op1 = (mpa_num_base *)op1;
mpanum mpa_op2 = (mpa_num_base *)op2;
mpa_add(mpa_dest, mpa_op1, mpa_op2, mempool);
}
static int mod(void *a, void *b, void *c)
{
LTC_ARGCHK(a != NULL);
LTC_ARGCHK(b != NULL);
LTC_ARGCHK(c != NULL);
mpa_mod((mpanum) c, (const mpanum) a, (const mpanum) b, external_mem_pool);
if (mpa_cmp_short(c, 0) < 0) {
mpa_add(c, c, b, external_mem_pool);
}
return CRYPT_OK;
}
/*------------------------------------------------------------
*
* mpa_add_mod
*
*/
void mpa_add_mod(mpanum dest,
const mpanum op1,
const mpanum op2, const mpanum n, mpa_scratch_mem pool)
{
mpanum tmp_dest;
mpa_alloc_static_temp_var(&tmp_dest, pool);
mpa_add(tmp_dest, op1, op2, pool);
mpa_div(NULL, dest, tmp_dest, n, pool);
mpa_free_static_temp_var(&tmp_dest, pool);
}
/*
* TEE_BigIntSubMod
*/
void TEE_BigIntSubMod(TEE_BigInt *dest, const TEE_BigInt *op1,
const TEE_BigInt *op2, const TEE_BigInt *n)
{
mpanum mpa_dest = (mpa_num_base *)dest;
mpanum mpa_op1 = (mpa_num_base *)op1;
mpanum mpa_op2 = (mpa_num_base *)op2;
mpanum mpa_n = (mpa_num_base *)n;
if (TEE_BigIntCmpS32(n, 2) < 0)
TEE_BigInt_Panic("Modulus is too short");
mpa_sub_mod(mpa_dest, mpa_op1, mpa_op2, mpa_n, mempool);
if (mpa_cmp_short(mpa_dest, 0) < 0)
mpa_add(mpa_dest, mpa_dest, mpa_n, mempool);
}
/*------------------------------------------------------------
*
* mpa_inv_mod
*
*/
int mpa_inv_mod(mpanum dest,
const mpanum op, const mpanum n, mpa_scratch_mem pool)
{
mpanum gcd;
mpanum tmp_dest;
int mem_marker;
int res;
if (mpa_cmp_short(op, 1) == 0) {
mpa_set_S32(dest, 1);
return 0;
}
mem_marker = (dest == op);
if (mem_marker)
mpa_alloc_static_temp_var(&tmp_dest, pool);
else
tmp_dest = dest;
mpa_alloc_static_temp_var(&gcd, pool);
/* The function mpa_extended_gcd behaves badly if tmp_dest = op */
mpa_extended_gcd(gcd, tmp_dest, NULL, op, n, pool);
res = mpa_cmp_short(gcd, 1);
if (mem_marker) {
mpa_copy(dest, tmp_dest);
mpa_free_static_temp_var(&tmp_dest, pool);
}
mpa_free_static_temp_var(&gcd, pool);
if (res == 0) {
while (mpa_cmp_short(dest, 0) < 0)
mpa_add(dest, dest, n, pool);
return 0;
} else {
return -1;
}
}
