Menu-Driven Interface:
BrownBear offers a straightforward menu-driven interface, making it accessible to users of all technical backgrounds. Users are presented with a range of options, including encryption, decryption, key management, and program exit.

Substitution Cipher:
The program employs a substitution cipher to obfuscate the input text before encryption. This classical cryptographic technique substitutes each character in the plaintext with another character based on a predefined key. By doing so, it adds an additional layer of security to the encryption process.

AES Encryption:
BrownBear utilizes Advanced Encryption Standard (AES), a widely recognized and trusted encryption algorithm, to encrypt the substituted text. AES is known for its robust security and efficiency, making it suitable for protecting sensitive data.

Base64 Encoding:
To ensure compatibility and safe transmission of encrypted data, BrownBear employs Base64 encoding. This encoding scheme converts binary data into a printable ASCII string, facilitating its exchange across different systems without data loss or corruption.

Key and IV Generation:
The program features functionalities for generating random AES keys and Initialization Vectors (IVs) when needed. These cryptographic components are crucial for securing the encryption process and enhancing the confidentiality of the encrypted data.

Error Handling:
BrownBear incorporates robust error handling mechanisms to gracefully manage exceptions and unexpected scenarios. By providing informative error messages, it assists users in troubleshooting issues and ensuring smooth operation.