diff --git a/lib/nettle/int/rsa-keygen-fips186.c b/lib/nettle/int/rsa-keygen-fips186.c

index 624aa36..b064b45 100644

--- a/lib/nettle/int/rsa-keygen-fips186.c

+++ b/lib/nettle/int/rsa-keygen-fips186.c

@@ -27,7 +27,6 @@

 #include "config.h"

 #endif

-#include <assert.h>

 #include <stdlib.h>

 #include <stdio.h>

 #include <string.h>

@@ -337,10 +336,16 @@ _rsa_generate_fips186_4_keypair(struct rsa_public_key *pub,

 	mpz_mul(pub->n, key->p, key->q);

-	assert(mpz_sizeinbase(pub->n, 2) == n_size);

+	if (mpz_sizeinbase(pub->n, 2) != n_size) {

+		ret = 0;

+		goto cleanup;

+	}

 	/* c = q^{-1} (mod p) */

-	assert(mpz_invert(key->c, key->q, key->p) != 0);

+	if (mpz_invert(key->c, key->q, key->p) == 0) {

+		ret = 0;

+		goto cleanup;

+	}

 	mpz_sub_ui(p1, key->p, 1);

 	mpz_sub_ui(q1, key->q, 1);

@@ -352,6 +357,12 @@ _rsa_generate_fips186_4_keypair(struct rsa_public_key *pub,

 		goto cleanup;

 	}

+	/* check whether d > 2^(nlen/2) -- FIPS186-4 5.3.1 */

+	if (mpz_sizeinbase(key->d, 2) < n_size/2) {

+		ret = 0;

+		goto cleanup;

+	}

+

 	/* Done! Almost, we must compute the auxillary private values. */

 	/* a = d % (p-1) */

 	mpz_fdiv_r(key->a, key->d, p1);

@@ -362,7 +373,10 @@ _rsa_generate_fips186_4_keypair(struct rsa_public_key *pub,

 	/* c was computed earlier */

 	pub->size = key->size = (n_size + 7) / 8;

-	assert(pub->size >= RSA_MINIMUM_N_OCTETS);

+	if (pub->size < RSA_MINIMUM_N_OCTETS) {

+		ret = 0;

+		goto cleanup;

+	}

 	ret = 1;

  cleanup: