A quantum random number generator (QRNG) as a genuine source of randomness is essential in many applications, such as number simulation and cryptography. Recently, a source-independent quantum random number generator (SI-QRNG), which can generate secure random numbers with untrusted sources, has been realized. However, the measurement loopholes of the trusted but imperfect devices used in SI-QRNGs have not yet been fully explored, which will cause security problems, especially in high-speed systems. Here, we point out and evaluate the security loopholes of practical imperfect measurement devices in SI-QRNGs. We also provide corresponding countermeasures to prevent these information leakages by recalculating the conditional minimum entropy and adding a monitor. Furthermore, by taking into account the finite-size effect, we show that the influence of the afterpulse can exceed that of the finite-size effect with the large number of sampled rounds. Our protocol is simple and effective, and it promotes the security of SI-QRNG in practice as well as the compatibility with high-speed measurement devices, thus paving the way for constructing ultrafast and security-certified commercial SI-QRNG systems.

量子随机数发生器（QRNG）作为真正的随机性源在许多应用中至关重要，例如数字仿真和密码学。近来，已经实现了一种与源无关的量子随机数发生器（SI-QRNG），该发生器可以生成不受信任的源的安全随机数。但是，尚未充分探索SI-QRNG中使用的受信任但不完善的设备的测量漏洞，这会引起安全问题，尤其是在高速系统中。在此，我们指出并评估了SI-QRNG中实际不完美测量设备的安全漏洞。我们还通过重新计算条件最小熵并添加监视器来提供相应的对策，以防止这些信息泄漏。此外，考虑到有限尺寸效应，我们表明，在大量采样回合中，后脉冲的影响可以超过有限大小效应的影响。我们的协议简单有效，它在实践中提高了SI-QRNG的安全性以及与高速测量设备的兼容性，从而为构建超快速且经过安全认证的商业SI-QRNG系统铺平了道路。