PEM_read_PrivateKey
pktmp = PEM_read_PrivateKey(fp, NULL, cb, u);
pktmp = PEM_read_PrivateKey(fp, NULL, cb, u);
pktmp = PEM_read_PrivateKey(fp, NULL, cb, u);
pkey = PEM_read_PrivateKey(fp, NULL, NULL, NULL);
key = PEM_read_PrivateKey(keyfp, NULL, NULL, NULL);