Hardcoded Cryptographic Keys and Weak IV Generation in linqi

The linqi application contains hardcoded cryptographic keys. Additionally, the application uses a weak algorithm with a limited ASCII charset to dynamically generate Initialization Vectors (IVs) for AES/CBC encryption, making known-plaintext attacks feasible. An attacker with local access can leverage these vulnerabilities to decrypt sensitive obfuscated strings, including ConnectionString values containing database credentials from appsettings.json.