Playfair cipher: Issues in current implementation

[kobby-pentangeli]

1. Input Validation Attacks:

• Since the implementation does not validate the characters in the keyword string (other than deduplicating and removing characters not in the alphabet), it might be susceptible to attacks where an invalid keyword is used to create a matrix that doesn't function correctly.

2. Panic Conditions:

• If there are conditions under which the program could panic (like array index out of bounds), an attacker might be able to craft inputs that cause the program to crash, creating a Denial-of-Service (DoS) condition. Thus, we need to ensure that the program does not panic under any circumstances to prevent such potential DoS attacks. One such solution is a robust error handling.