int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, const BIGNUM *add,
const BIGNUM *rem, BN_GENCB *cb) {
BIGNUM *t;
int found = 0;
int i, j, c1 = 0;
BN_CTX *ctx;
int checks = BN_prime_checks_for_size(bits);
if (bits < 2) {
/* There are no prime numbers this small. */
OPENSSL_PUT_ERROR(BN, BN_R_BITS_TOO_SMALL);
return 0;
} else if (bits == 2 && safe) {
/* The smallest safe prime (7) is three bits. */
OPENSSL_PUT_ERROR(BN, BN_R_BITS_TOO_SMALL);
return 0;
}
ctx = BN_CTX_new();
if (ctx == NULL) {
goto err;
}
BN_CTX_start(ctx);
t = BN_CTX_get(ctx);
if (!t) {
goto err;
}
loop:
/* make a random number and set the top and bottom bits */
if (add == NULL) {
if (!probable_prime(ret, bits)) {
goto err;
}
} else {
if (safe) {
if (!probable_prime_dh_safe(ret, bits, add, rem, ctx)) {
goto err;
}
} else {
if (!probable_prime_dh(ret, bits, add, rem, ctx)) {
goto err;
}
}
}
if (!BN_GENCB_call(cb, BN_GENCB_GENERATED, c1++)) {
/* aborted */
goto err;
}
if (!safe) {
i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb);
if (i == -1) {
goto err;
} else if (i == 0) {
goto loop;
}
} else {
/* for "safe prime" generation, check that (p-1)/2 is prime. Since a prime
* is odd, We just need to divide by 2 */
if (!BN_rshift1(t, ret)) {
goto err;
}
for (i = 0; i < checks; i++) {
j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, NULL);
if (j == -1) {
goto err;
} else if (j == 0) {
goto loop;
}
j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, NULL);
if (j == -1) {
goto err;
} else if (j == 0) {
goto loop;
}
if (!BN_GENCB_call(cb, i, c1 - 1)) {
goto err;
}
/* We have a safe prime test pass */
}
}
/* we have a prime :-) */
found = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
return found;
}
BIGNUM *BN_generate_prime(BIGNUM *ret, int bits, int safe,
const BIGNUM *add, const BIGNUM *rem,
void (*callback)(int,int,void *), void *cb_arg)
{
BIGNUM *rnd=NULL;
BIGNUM t;
int found=0;
int i,j,c1=0;
BN_CTX *ctx;
int checks = BN_prime_checks_for_size(bits);
ctx=BN_CTX_new();
if (ctx == NULL) goto err;
if (ret == NULL)
{
if ((rnd=BN_new()) == NULL) goto err;
}
else
rnd=ret;
BN_init(&t);
loop:
/* make a random number and set the top and bottom bits */
if (add == NULL)
{
if (!probable_prime(rnd,bits)) goto err;
}
else
{
if (safe)
{
if (!probable_prime_dh_safe(rnd,bits,add,rem,ctx))
goto err;
}
else
{
if (!probable_prime_dh(rnd,bits,add,rem,ctx))
goto err;
}
}
/* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */
if (callback != NULL) callback(0,c1++,cb_arg);
if (!safe)
{
i=BN_is_prime_fasttest(rnd,checks,callback,ctx,cb_arg,0);
if (i == -1) goto err;
if (i == 0) goto loop;
}
else
{
/* for "safe prime" generation,
* check that (p-1)/2 is prime.
* Since a prime is odd, We just
* need to divide by 2 */
if (!BN_rshift1(&t,rnd)) goto err;
for (i=0; i<checks; i++)
{
j=BN_is_prime_fasttest(rnd,1,callback,ctx,cb_arg,0);
if (j == -1) goto err;
if (j == 0) goto loop;
j=BN_is_prime_fasttest(&t,1,callback,ctx,cb_arg,0);
if (j == -1) goto err;
if (j == 0) goto loop;
if (callback != NULL) callback(2,c1-1,cb_arg);
/* We have a safe prime test pass */
}
}
/* we have a prime :-) */
found = 1;
err:
if (!found && (ret == NULL) && (rnd != NULL)) BN_free(rnd);
BN_free(&t);
if (ctx != NULL) BN_CTX_free(ctx);
return(found ? rnd : NULL);
}
int
BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, const BIGNUM *add,
const BIGNUM *rem, BN_GENCB *cb)
{
BIGNUM *t;
int found = 0;
int i, j, c1 = 0;
BN_CTX *ctx;
int checks = BN_prime_checks_for_size(bits);
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
if ((t = BN_CTX_get(ctx)) == NULL)
goto err;
loop:
/* make a random number and set the top and bottom bits */
if (add == NULL) {
if (!probable_prime(ret, bits))
goto err;
} else {
if (safe) {
if (!probable_prime_dh_safe(ret, bits, add, rem, ctx))
goto err;
} else {
if (!probable_prime_dh(ret, bits, add, rem, ctx))
goto err;
}
}
/* if (BN_mod_word(ret,(BN_ULONG)3) == 1) goto loop; */
if (!BN_GENCB_call(cb, 0, c1++))
/* aborted */
goto err;
if (!safe) {
i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb);
if (i == -1)
goto err;
if (i == 0)
goto loop;
} else {
/* for "safe prime" generation,
* check that (p-1)/2 is prime.
* Since a prime is odd, We just
* need to divide by 2 */
if (!BN_rshift1(t, ret))
goto err;
for (i = 0; i < checks; i++) {
j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, cb);
if (j == -1)
goto err;
if (j == 0)
goto loop;
j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, cb);
if (j == -1)
goto err;
if (j == 0)
goto loop;
if (!BN_GENCB_call(cb, 2, c1 - 1))
goto err;
/* We have a safe prime test pass */
}
}
/* we have a prime :-) */
found = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
bn_check_top(ret);
return found;
}
