THE QUANTUM INTELLIGENCER

High Memory Masked Convolutional Codes: A Scalable and Secure Post-Quantum Cryptosystem In Plain English: This paper tackles the problem of creating secure digital communication that can resist attacks from future quantum computers. The authors designed a new encryption method that scrambles messages more thoroughly than older systems by using complex patterns and adding extra randomness, making it extremely hard for attackers to crack. They also made it efficient enough to work well on real devices by allowing fast, parallel decoding. This matters because as quantum computers advance, we need new kinds of encryption to protect everything from online banking to private messages, and this system could offer both stronger security and better performance for long messages. Summary: The paper proposes a novel post-quantum cryptosystem based on high-memory masked convolutional codes, offering improvements over traditional block-code-based systems like McEliece. By leveraging convolutional codes with extended memory and masking techniques, the scheme supports arbitrary-length plaintexts with linear-time decryption and uniform computational cost per bit, enabling efficient scalability. Security is enhanced through a higher rate of random error injection compared to block-code approaches and additional noise introduced via polynomial division, which obscures the underlying code structure. Semi-invertible transformations are used to generate dense, random-like generator matrices that hide algebraic properties and resist structural cryptanalysis. The resulting system achieves a cryptanalytic security margin exceeding that of the classic McEliece cryptosystem by a factor greater than 2^100. Decryption is efficiently implemented using an array of parallel Viterbi decoders, supporting high-performance hardware and software deployment, making the scheme a promising candidate for practical quantum-resistant public-key cryptography. Key Points: - The cryptosystem is based on high-memory masked convolutional codes rather than traditional block codes. It supports variable-length messages with linear-time decryption and consistent per-bit computational cost. Security is strengthened by injecting more random errors than in block-code systems and adding noise via polynomial division. Semi-invertible transformations create random-like generator matrices that resist structural attacks. The scheme's security exceeds that of the McEliece system by a factor greater than 2^100. Decryption uses parallel Viterbi decoders for efficiency in both hardware and software. The design enables seamless scalability and practical deployment in post-quantum environments. Notable Quotes: - "Our construction offers both stronger cryptographic security and greater flexibility." — Describing the core advantage of the proposed system. - "Security is reinforced through a higher-rate injection of random errors than in block-code approaches, along with additional noise introduced via polynomial division..." — Highlighting dual-layer security mechanisms. - "Consequently, the scheme achieves cryptanalytic security margins exceeding those of the classic McEliece system by factors greater than 2^100." — Emphasizing the dramatic security improvement. - "Decryption at the recipient employs an array of parallel Viterbi decoders, enabling efficient hardware and software implementation..." — Stating the practical implementation benefits. Data Points: - Security margin exceeds that of the McEliece cryptosystem by a factor greater than 2^100. The system supports arbitrary plaintext lengths. Decryption operates in linear time with uniform per-bit computational cost. Implementation uses parallel Viterbi decoders for efficient decoding. The scheme is based on high-memory masked convolutional codes with polynomial division for added noise. Controversial Claims: - The claim that the cryptanalytic security margin exceeds that of the McEliece system by a factor greater than 2^100 is highly significant and may be considered speculative or in need of independent verification, as such a margin implies an unprecedented level of resistance to known attacks. Additionally, the assertion that semi-invertible transformations fully conceal algebraic properties and resist all known structural attacks has not yet been validated by the broader cryptographic community, making it a strong claim subject to future scrutiny. Technical Terms: - Post-quantum cryptography (PQC), convolutional codes, high-memory codes, masked codes, block codes, error-correction capability, generator matrix, semi-invertible transformations, structural attacks, cryptanalytic security margin, McEliece cryptosystem, random error injection, polynomial division, Viterbi decoder, linear-time decryption, quantum-resistant public-key cryptosystems. —Ada H. Pemberley Dispatch from The Prepared E0