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<HTML> |
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<HEAD> |
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<TITLE>Stage One of Encryption</TITLE> |
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<SCRIPT LANGUAGE = "Javascript"> |
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var W, i, S; |
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function Begin() |
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{ var i, A,B,S, T, Number, Length, M, First, Second, Third, Fourth; |
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W = document.EncryptForm.Phrase.value; |
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Length = W.length; |
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S = "It has " + Length + " characters."; |
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Append = "That is an odd number. I will append an X to the end and proceed with the encryption." |
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if (W.length % 2 == 1) |
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{ S = S + Append; |
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W = W + "X"; |
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Length = Length + 1 } |
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var Originals = new Array(Length/2); |
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document.EncryptForm.Comment.value = S; |
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T = "Its original numerical representation is "; |
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document.EncryptForm.Digits.value = T; |
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for (i = 0; i < Length ; i = i + 2) |
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{ A = W.charCodeAt(i) ; |
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B = W.charCodeAt(i+1) ; |
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Number = 100*A + B; |
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Originals[i/2] = Number; |
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} |
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document.EncryptForm.plain.value = Originals.join(" ");; |
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var Scrambleds = new Array (Length/2); |
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var Digits = new Array(4) |
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function power(k) |
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{ var i, N; |
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N = 1; |
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for (i = 1; i <= k; i = i+ 1) N = N * 10; |
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return N; |
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} |
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for (i = 0; i < Length/2; i = i + 1) |
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{ |
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M = Originals[i]; |
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for (j = 0; j <= 3; j = j+ 1) |
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{ Digits[j] = Math.floor(M/power(j)); |
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Digits[j] = ( Digits[j] + 7) % 10; } |
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M = 0; |
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for (j = 0; j <= 3; j = j+ 1) |
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M = M + Digits[j] * power(3-j); |
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Scrambleds[i] = M |
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} |
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document.EncryptForm.Scrambled.value = Scrambleds.join(" "); |
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} |
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</SCRIPT> |
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</HEAD> |
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<BODY BGCOLOR = "white"> |
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<FORM NAME = "EncryptForm"> |
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Enter a word or phrase <INPUT NAME = "Phrase" SIZE = 80 TYPE = "text"> |
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<BR> |
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<INPUT TYPE = "button" VALUE = "Click to Encrypt" SIZE = "20" |
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ONCLICK = "Begin()" > |
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<BR> |
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<TEXTAREA NAME = "Comment" ROWS =4 COLS = 50 TYPE = "text"> </TEXTAREA> |
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<BR> |
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<INPUT NAME = "Digits" SIZE = 50 TYPE = "text"> |
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<BR> |
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<TEXTAREA NAME = "plain" ROWS = 5 COLS = 50 TYPE = "text"> </TEXTAREA> |
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<BR> |
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<H2>The encrypted message is: |
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<BR> |
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<TEXTAREA NAME = "Scrambled" ROWS = 5 COLS = 50 TYPE = "text"> |
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</TEXTAREA> |
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</FORM> |
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</BODY> |
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</HTML> |