Design and implement 5 different string-based encryption methods with comparative analysis: 1) A polyalphabetic substitution cipher 2) A format-preserving encryption for alphanumeric strings 3) A homomorphic encryption approach allowing operations on encrypted strings 4) A string obfuscation technique using encoding and decoy characters 5) A quantum-resistant string encryption method. For each method, include: algorithm specification, implementation, security analysis, performance benchmarks, key management approach, and example use cases. Discuss trade-offs between security, performance, and usability.