RQC

RQC is an acronym with multiple meanings across different fields. In cryptography, RQC stands for Rank Quasi-Cyclic, a code-based public-key cryptosystem designed for post-quantum security. Rank Quasi-Cyclic cryptosystems use the rank metric over a finite extension field and employ a quasi-cyclic structure to achieve smaller key sizes relative to traditional McEliece-type schemes. A typical construction encodes messages with a rank-metric code; the public key is a generator or parity-check matrix of such a code, derived to mask the underlying structure, while the private key provides a trapdoor that allows efficient decoding. The security of RQC rests on the hardness of decoding in the rank metric (the Rank Decoding problem) and related problems. Parameter choices aim to resist known attacks, including specialized adaptations of information-set decoding in the rank metric, while keeping keys practical for real-world use. RQC has been evaluated in the context of post-quantum cryptography and has appeared in academic discussions and standardization processes as researchers compare its performance and security with other code-based schemes.

In other domains, RQC is an acronym that can refer to different organizations or concepts depending on context. No single alternative meaning is universally dominant, so readers should rely on surrounding text to identify the intended sense.