Starting with a random source that remained slightly predictable, ETH Zurich researchers generated a string of perfectly random bits. The experiment turns a cornerstone of quantum physics into a cryptographic tool.
Researchers from ETH Zurich report the first experimental implementation of a protocol known as randomness amplification. By feeding weakly random numbers into a quantum system, they manage to generate a string of perfectly random numbers. As a source of complete unpredictability, the work could help improve the security of encryption methods.
Imperfect randomness is more than a theoretical threat. It’s been implicated in real-world security failures, such as the 2024 Putty vulnerability, in which one of the world’s most widely used SSH clients had a flaw in its random-number generation for cryptographic signatures. In 2025, a bug was found in AMD processors, in which a hardware random-number instruction would generate predictable values while falsely reporting success.
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