ecdh: Use bignum_bin2bn.

src/curve25519.c

@@ -90,7 +90,7 @@ static int ssh_curve25519_build_k(ssh_session session) {
 	  crypto_scalarmult(k, session->next_crypto->curve25519_privkey,
 			  session->next_crypto->curve25519_server_pubkey);
 
-  BN_bin2bn(k, CURVE25519_PUBKEY_SIZE, session->next_crypto->k);
+  bignum_bin2bn(k, CURVE25519_PUBKEY_SIZE, session->next_crypto->k);
 
 #ifdef DEBUG_CRYPTO
     ssh_print_hexa("Session server cookie",

src/ecdh.c

@@ -154,7 +154,7 @@ static int ecdh_build_k(ssh_session session) {
       return -1;
   }
 
-  BN_bin2bn(buffer, len, session->next_crypto->k);
+  bignum_bin2bn(buffer, len, session->next_crypto->k);
   free(buffer);
 
   EC_KEY_free(session->next_crypto->ecdh_privkey);