iss-security / hw-credit_card_crypto Goto Github PK

Hi Soumya,

After taking a look at the double_trans_cipher.rb and aes_cipher.rb, I found it difficult to DRY out the spec/crypto_spec.rb since the order of the arguments are not consistent with those in substitution_cipher.rb.

double_trans_cipher.rb

module DoubleTranspositionCipher
  def encrypt(key)
    # implementation
  end
  def Decrypt()
    # implementation
  end
end

The only way I knew to invoke encrypt and decrypt is mixin (am I correct ? ).

Btw, should decrypt in DoubleTranspositionCipher also take a key as parameter (for the PRNG).

aes_cipher.rb

require 'openssl'

module AesCipher
  def self.encrypt(key, plaintext)
    # implementation
  end
  def self.decrypt(key, aes_crypt)
    # # implementation
  end
end

This looks pretty good. However, the order of the arguments is opposite to the order in substitution_cipher.rb which is defined as:

self.encrypt(doc, key)
  # implementation
end

So, is it possible to change the method definitions?

- Cheng-Yu

Hi Professor,

In part D of the assignment, we're going to write our own test cases for the hash function.
However, something looks weird in spec/hash_spec.rb:

  it 'should produce different hashes for different information' do
    # TODO: implement this test
  end

This test case is designed to test that different hashes will be generated if different information is given, which is not necessary true.

As I know, there exists some hash collisions (although the probability is extremely small) that may cause failure on this test case.

So should we ignore the probability of collisions or delete this test case?

- Cheng-Yu