/*
* call-seq:
* bn.prime_fasttest? => true | false
* bn.prime_fasttest?(checks) => true | false
* bn.prime_fasttest?(checks, trial_div) => true | false
*
* === Parameters
* * +checks+ - integer
* * +trial_div+ - boolean
*/
static VALUE
ossl_bn_is_prime_fasttest(int argc, VALUE *argv, VALUE self)
{
BIGNUM *bn;
VALUE vchecks, vtrivdiv;
int checks = BN_prime_checks, do_trial_division = 1;
rb_scan_args(argc, argv, "02", &vchecks, &vtrivdiv);
if (!NIL_P(vchecks)) {
checks = NUM2INT(vchecks);
}
GetBN(self, bn);
/* handle true/false */
if (vtrivdiv == Qfalse) {
do_trial_division = 0;
}
switch (BN_is_prime_fasttest(bn, checks, NULL, ossl_bn_ctx, NULL, do_trial_division)) {
case 1:
return Qtrue;
case 0:
return Qfalse;
default:
ossl_raise(eBNError, NULL);
}
/* not reachable */
return Qnil;
}
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_is_prime(const BIGNUM *a, int checks, void (*callback)(int,int,void *),
BN_CTX *ctx_passed, void *cb_arg)
{
return BN_is_prime_fasttest(a, checks, callback, ctx_passed, cb_arg, 0);
}
DSA *DSA_generate_parameters(int bits,
unsigned char *seed_in, int seed_len,
int *counter_ret, unsigned long *h_ret,
void (*callback)(int, int, void *),
void *cb_arg)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int k,n=0,i,b,m=0;
int counter=0;
int r=0;
BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL;
unsigned int h=2;
DSA *ret=NULL;
if (bits < 512) bits=512;
bits=(bits+63)/64*64;
if (seed_len < 20)
seed_in = NULL; /* seed buffer too small -- ignore */
if (seed_len > 20)
seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits*/
if ((seed_in != NULL) && (seed_len == 20))
memcpy(seed,seed_in,seed_len);
if ((ctx=BN_CTX_new()) == NULL) goto err;
if ((ctx2=BN_CTX_new()) == NULL) goto err;
if ((ctx3=BN_CTX_new()) == NULL) goto err;
if ((ret=DSA_new()) == NULL) goto err;
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
BN_CTX_start(ctx2);
r0 = BN_CTX_get(ctx2);
g = BN_CTX_get(ctx2);
W = BN_CTX_get(ctx2);
q = BN_CTX_get(ctx2);
X = BN_CTX_get(ctx2);
c = BN_CTX_get(ctx2);
p = BN_CTX_get(ctx2);
test = BN_CTX_get(ctx2);
if (test == NULL) goto err;
if (!BN_lshift(test,BN_value_one(),bits-1)) goto err;
for (;;)
{
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
if (callback != NULL) callback(0,m++,cb_arg);
if (!seed_len)
{
RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
seed_is_random = 1;
}
else
{
seed_is_random = 0;
seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
}
memcpy(buf,seed,SHA_DIGEST_LENGTH);
memcpy(buf2,seed,SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
/* step 2 */
EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
/* step 4 */
r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, cb_arg, seed_is_random);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if (callback != NULL) callback(2,0,cb_arg);
if (callback != NULL) callback(3,0,cb_arg);
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;)
{
if (callback != NULL && counter != 0)
callback(0,counter,cb_arg);
/* step 7 */
if (!BN_zero(W)) goto err;
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
goto err;
if (!BN_lshift(r0,r0,160*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,bits-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, cb_arg, 1);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if (callback != NULL) callback(2,1,cb_arg);
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if (callback != NULL) callback(3,1,cb_arg);
ok=1;
err:
if (!ok)
{
if (ret != NULL) DSA_free(ret);
}
else
{
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=0;
goto err;
}
if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if (ctx != NULL) BN_CTX_free(ctx);
if (ctx2 != NULL)
{
BN_CTX_end(ctx2);
BN_CTX_free(ctx2);
}
if (ctx3 != NULL) BN_CTX_free(ctx3);
if (mont != NULL) BN_MONT_CTX_free(mont);
return(ok?ret:NULL);
}
