if(chacha_poly1305_encrypt_iv96(ctx, seqbuf, config->buf, config->len, buf, &len)) {
success = fwrite(seqbuf, sizeof(seqbuf), 1, f) == 1 && fwrite(buf, len, 1, f) == 1;
if(chacha_poly1305_encrypt_iv96(ctx, seqbuf, config->buf, config->len, buf, &len)) {
success = fwrite(seqbuf, sizeof(seqbuf), 1, f) == 1 && fwrite(buf, len, 1, f) == 1;