create a single function in matlab that can both encrypt and decrypt a message using an porta cipher

1. Remove any special characters, punctuation and spaces from the message to be encoded.

2. Convert all lowercase letters to uppercase and use the 26-character alphabet used to create the encryption squares.

3. Generate the encryption/decryption key.

4. Encrypt/decrypt the message and output the result.

. 5. Decrypt the given message.

cannot use find function

must use loops and branching statements