We are seeking a specialist with a strong background in designing and analyzing symmetric block ciphers to collaborate on a research-oriented project focused on developing a new encryption structure. This project requires a full, functional implementation of the cipher in Python only, delivered within a short timeframe. This is not a theoretical consultation; the work must result in a complete and testable software implementation. Candidates must demonstrate the ability to understand mathematical models of modern cipher design and translate them into precise, verifiable code. Required Tasks • Design the full structural architecture of the proposed block cipher. • Implement all algorithmic components exclusively in Python. • Develop test vectors and validation scripts to ensure functional correctness. • Deliver a fully working, ready-to-run implementation. • Complete the project within a short delivery window. Expected Deliverables • A complete Python file (or module) containing the full cipher implementation. • Official test vectors and unit tests validating correctness. • A concise technical guide explaining the structure and how to use the implementation. ⸻ Required Qualifications • Demonstrated experience in designing or analyzing symmetric-key encryption algorithms. • Strong theoretical understanding of SPN and Feistel constructions. • Practical or theoretical knowledge of differential and linear cryptanalysis. • Ability to produce clean, well-documented, testable Python code. • Ability to work efficiently under tight time constraints. ⸻ Screening Questions (Must be answered in the proposal) 1. Do you have prior experience in designing or analyzing block ciphers, not just implementing existing algorithms such as AES? 2. Have you ever performed differential or linear cryptanalysis on a cipher? 3. Are you theoretically familiar with SPN and Feistel structures? 4. Have you contributed to or co-authored any academic publication in security or cryptography? 5. Can you formally define IND-CPA security and explain how it can be tested experimentally?