• Hill Cipher program is implemented using OOP, there are two crypter classes, one for text and one for audio. They inherit from the parent class hill_cipher.

• Key matrix is generated automatically at the moment of creating crypter object, or you can pass certain key as a parameter. You can update the key any time you want.

• Text crypter only works for Georgian text and audio crypter only for .wav files.

• Methods of audio crypter updates files on its own, but text crypter just returns the modified text.

• The program just uses inverse matrix to decrypt data, it doesn't solve the linear system.

For more detailed information see the comments in code!

• Text crypter is fully accurate, it decrypts the text including punctuation marks and result is exactly the same text as original one since it uses maximal certain modular range.
• Audio crypter is not fully accurate, since it uses only specific modular range, while some numeric data of audio can be out of this modular range, so it is not possible to recover data completely with this implementation.

The Program performance is not the best, however it is fast enough to use in some certain cases, since generating the key matrix is the most inefficient task in my code, but it generates only once during the process and uses same matrix for the data at default. It is important that the time is linearly dependent on data size, because number of blocks are linearly dependent on data size and each block is multiplied by the same key only once. Thus, it needs asymptotically the same amount of time for bigger data as smaller one.

The storage efficiency of the code is reasonable, and the memory requirements are generally influenced by the key size and the length of the input text. Efficiency for key is O(size^2) and for text it is O(length). Same happens for audio, because it needs linear storage efficiency for audio file, and it uses the matrix generated using the same method as for text

Pros:

• Customizable alphabet mapping
• High accuracy of Key generation and validation
• Well-structured and readable using OOP and commenting

Cons:

• Alphabet Mapping Limitation, only predefined characters
• Decrypted audio is not fully the same as original
• Limited Error Handling

In the real world, only hill cipher is not generally used. There are more advanced cryptographic techniques to encrypt data, However, generally, this code can be applied to many cases:

• Safe communication in chats for text and voice messages by not letting unauthorised user to read this data.
• Exam paper encryption can be a useful way to prevent leaking of the information about it.
• Military communication involves also confidentiality. Transmitted messages must remain secure by encrypting.