You are to develop an original encryption/decryption system. Do not copy in whol

Question

You are to develop an original encryption/decryption system. Do not copy in whole a system from the materials above, you may use the systems explained above as guides and building points but cannot simply replicate the systems. Write an explanation of your system, how to encrypt and decrypt a message, so that others can understand and use it. Your paper must include a step by step explanation with examples. Using your explanation I should be able to encrypt and decrypt any message. You are to include an assessment of how secure your system is.

Can anyone help me out with this please. Only has to be a half a page or one page and can be simple, not asking for anything longer than a page

Explanation / Answer

Let us design a simple encryption system where the plaintext is in alphanumeric form. Let us assign numeric codes to the alphabets (0-25) for A to Z and (26-34) for digits 0-9, 35 for spaces and (36-40) for special characters , . ! ; and ?

The encryption system takes a key which is a number, then each letter of the plaintext is converted to it's numeric form. The key is added to each of the numeric forms (modulo 41) and then converted back to alphanumeric form to obtain the cipher text.

For example, let the plaintext be "hi !". The numeric representation would be 7 8 35 38.

Let the key be 5. So, adding it to the numeric representation (mod 41) = 12 13 40 2

Converting to alphanumeric, it becomes "lm?c" which is the ciphertext.

To get the plaintext convert the ciphertext to numeric form 12 13 40 2. Add 41 - key = 36 to each number to get

48 49 76 38. Now perform moduulo 41 to get 7 8 35 38

Convert it back to alphanumeric form to get "hi !" which is the plaintext

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.