https (the s stands for secure)

Cryptography – secret writing

Encryption – act of converting plain text into ciphertext (ex: hello -> khoor)

Decryption – converting back to original text (ex: khoor -> hello)

Symmetric encryption – a key for translation. same key for each person, sender and reciever

Caesar Cipher – is a substitution cipher. Substitute 1 character for another (ex: if the key is 3 -> shift the alphabet by 3 which converts a->d  b->e  c->f and so on.

All caps for a variable name indicates the value of the variable does not change.

\n = enter


  1. Post a screenshot of your code for the caesarDecrypt function.
  2. Explain the difference between a function and a procedure. Give an example of a function.
    1. A function is a procedure that returns a value (a result). An example would be the Encrypt or Decrypt procedures in the Caesar Cipher app in this lesson. The Decrypt on is shown above.
  3. Explain the difference between global and local variables. Why are local variables easier to debug than global variables?
    1. Global variables can be used in any procedure or event handler in your app. A local variable can only be used in one procedure, the one it was defined in.
    2. Local variables are easier to debug because they are defined and used only within one procedure and therefore are isolated to one piece of your code.