ShiftCode --- Computer Science --- Haas
Write a JavaScript program to impliment Caesar's cipher.
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In cryptography the shift code, or Caesar cipher, is one of the
simplest and most widely known encryption techniques.
It is a type of substitution cipher in which each letter in the
text is replaced by a letter some fixed number of positions
down the alphabet. For example, with a shift of 3, A would be
replaced by D, B would become E, and so on.
The method was used by Julius Caesar to communicate
with his generals.
The encryption step performed by a Caesar cipher is often incorporated as
part of more complex schemes today.
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Example:
Computer >>
Enter a sentence:
User>> I LIKE PIZZA
Computer>>
Enter the shift distance:
User>> 4
Computer>>
Sentence: I LIKE PIZZA
Shift distance: 4
Result: M PMOI TMDDE
Below is some code to get you started.
<HTML>
<head>
<title>Shift Code </title>
</head>
<body>
<script language = "JavaScript">
/********************************************************************
Complete the unfinished program below.
********************************************************************/
// Here are some variables you might need //
var shifted = "";
var letter;
var position;
var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var sentence = prompt("Enter sentence:","I LIKE PIZZA").toUpperCase();
var shiftBy = parseInt(prompt("Shift by ","4"));
// <<< Complete the missing code >>>
/*** The following prints out the results ***/
document.write("<br>Sentence: " + sentence);
document.write("<br>Shift distance: " + shiftBy);
document.write("<br>Result: " + shifted);
</script>
</body>
</HTML>