up:: [[Post-Quantum Cryptography (PQC)]] # Code-Based Cryptography Code-based cryptography is a type of cryptographic method that relies on error-correcting codes to secure communications. As part of [[Post-Quantum Cryptography (PQC)]], it is designed to be secure against attacks from both classical and [[Quantum Computing|quantum computers]], making it a candidate for securing cryptographic functions in a future where [[quantum computing]] is prevalent. ## How It Works Code-based cryptography typically involves constructing a scenario where decoding a randomly chosen code is computationally hard, except for parties who possess a secret decoding [[algorithm]]. The most well-known code-based algorithm is the McEliece cryptosystem, which uses a specific class of error-correcting codes known as Goppa codes. Here's a simplified explanation: - **Key Generation:** Generate a public and a [[private key]] using error-correcting codes, where the [[private key]] is a secret error-correcting code. - **[[Encryption]]:** Use the [[public key]] to introduce errors into a plaintext message, essentially encoding it. - **Decryption:** Apply the [[private key]]'s error-correcting code to decode the message and correct the errors, revealing the original plaintext. ## Key Features - **Resistance to Quantum Attacks:** Utilizes mathematical problems that are currently believed to be resistant to both classical and [[quantum computing]] attacks. - **Error-Correcting Codes:** Leverages the robustness of error-correcting codes to secure communications, which inherently provides a method to correct errors in transmissions—a useful property for cryptographic resilience. ## Advantages - **Quantum Resilience:** Offers a secure method of [[encryption]] that is not vulnerable to known [[quantum computing]] [[Algorithm|algorithms]], such as [[Shor's algorithm]]. - **High Security Level:** Provides strong security assurances based on the hardness of decoding random linear codes, which is a well-studied problem. - **Efficiency:** While key sizes are typically large, the actual encryption and decryption processes can be efficient. ## Major Tools and Software - **Open Quantum Safe (OQS):** Provides open-source libraries to prototype [[quantum-resistant]] cryptography, including implementations of code-based [[cryptographic algorithms]]. - **liboqs:** A C library that includes support for various [[Post-Quantum Cryptography (PQC)|PQC]] algorithms, including code-based schemes. - **PQClean:** A project that provides clean, portable, and easy-to-use implementations of post-quantum cryptographic algorithms, with several code-based options available. ## Related Cybersecurity Policies - **[[NIST Post-Quantum Cryptography Standardization]] Process:** NIST is actively working to standardize post-quantum [[cryptographic algorithms]], including code-based cryptography, to prepare for the era of [[quantum computing]]. - **ETSI White Paper on Quantum Safe Cryptography and Security:** Discusses the implications of [[quantum computing]] on current security protocols and the role of quantum-safe algorithms, including code-based methods. ## Current Status Code-based cryptography is one of the leading candidates in the race to develop secure systems against quantum attacks. With ongoing research and development spurred by entities like NIST, it is poised to play a crucial role in future cryptographic standards. ## Revision History - **2024-04-14:** Entry created.