r0= &(ctx->bn[0]); r1= &(ctx->bn[1]); r2= &(ctx->bn[2]); r3= &(ctx->bn[3]); ctx->tos+=4;
BN_CTX_start(ctx); r0 = BN_CTX_get(ctx); r1 = BN_CTX_get(ctx); r2 = BN_CTX_get(ctx); r3 = BN_CTX_get(ctx); if (r3 == NULL) goto err;
RSA *RSA_generate_key(int bits, unsigned long e_value,	     void (*callback)(int,int,void *), void *cb_arg)	{	RSA *rsa=NULL;	BIGNUM *r0=NULL,*r1=NULL,*r2=NULL,*r3=NULL,*tmp;	int bitsp,bitsq,ok= -1,n=0,i;	BN_CTX *ctx=NULL,*ctx2=NULL;	ctx=BN_CTX_new();	if (ctx == NULL) goto err;	ctx2=BN_CTX_new();	if (ctx2 == NULL) goto err;	r0= &(ctx->bn[0]);	r1= &(ctx->bn[1]);	r2= &(ctx->bn[2]);	r3= &(ctx->bn[3]);	ctx->tos+=4;	bitsp=(bits+1)/2;	bitsq=bits-bitsp;	rsa=RSA_new();	if (rsa == NULL) goto err;	/* set e */ 	rsa->e=BN_new();	if (rsa->e == NULL) goto err;#if 1	/* The problem is when building with 8, 16, or 32 BN_ULONG,	 * unsigned long can be larger */	for (i=0; i<sizeof(unsigned long)*8; i++)		{		if (e_value & (1<<i))			BN_set_bit(rsa->e,i);		}#else	if (!BN_set_word(rsa->e,e_value)) goto err;#endif	/* generate p and q */	for (;;)		{		rsa->p=BN_generate_prime(NULL,bitsp,0,NULL,NULL,callback,cb_arg);		if (rsa->p == NULL) goto err;		if (!BN_sub(r2,rsa->p,BN_value_one())) goto err;		if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;		if (BN_is_one(r1)) break;		if (callback != NULL) callback(2,n++,cb_arg);		BN_free(rsa->p);		}	if (callback != NULL) callback(3,0,cb_arg);	for (;;)		{		rsa->q=BN_generate_prime(NULL,bitsq,0,NULL,NULL,callback,cb_arg);		if (rsa->q == NULL) goto err;		if (!BN_sub(r2,rsa->q,BN_value_one())) goto err;		if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;		if (BN_is_one(r1) && (BN_cmp(rsa->p,rsa->q) != 0))			break;		if (callback != NULL) callback(2,n++,cb_arg);		BN_free(rsa->q);		}	if (callback != NULL) callback(3,1,cb_arg);	if (BN_cmp(rsa->p,rsa->q) < 0)		{		tmp=rsa->p;		rsa->p=rsa->q;		rsa->q=tmp;		}	/* calculate n */	rsa->n=BN_new();	if (rsa->n == NULL) goto err;	if (!BN_mul(rsa->n,rsa->p,rsa->q,ctx)) goto err;	/* calculate d */	if (!BN_sub(r1,rsa->p,BN_value_one())) goto err;	/* p-1 */	if (!BN_sub(r2,rsa->q,BN_value_one())) goto err;	/* q-1 */	if (!BN_mul(r0,r1,r2,ctx)) goto err;	/* (p-1)(q-1) *//* should not be needed, since gcd(p-1,e) == 1 and gcd(q-1,e) == 1 *//*	for (;;)		{		if (!BN_gcd(r3,r0,rsa->e,ctx)) goto err;		if (BN_is_one(r3)) break;		if (1)			{			if (!BN_add_word(rsa->e,2L)) goto err;			continue;			}		RSAerr(RSA_F_RSA_GENERATE_KEY,RSA_R_BAD_E_VALUE);		goto err;		}*/	rsa->d=BN_mod_inverse(NULL,rsa->e,r0,ctx2);	/* d */	if (rsa->d == NULL) goto err;	/* calculate d mod (p-1) */	rsa->dmp1=BN_new();	if (rsa->dmp1 == NULL) goto err;	if (!BN_mod(rsa->dmp1,rsa->d,r1,ctx)) goto err;	/* calculate d mod (q-1) */	rsa->dmq1=BN_new();	if (rsa->dmq1 == NULL) goto err;	if (!BN_mod(rsa->dmq1,rsa->d,r2,ctx)) goto err;	/* calculate inverse of q mod p */	rsa->iqmp=BN_mod_inverse(NULL,rsa->q,rsa->p,ctx2);	if (rsa->iqmp == NULL) goto err;	ok=1;err:	if (ok == -1)		{		RSAerr(RSA_F_RSA_GENERATE_KEY,ERR_LIB_BN);		ok=0;		}	BN_CTX_free(ctx);	BN_CTX_free(ctx2);		if (!ok)		{		if (rsa != NULL) RSA_free(rsa);		return(NULL);		}	else		return(rsa);	}