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type Chaocipher:Mode
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enum
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int ENCRYPT, DECRYPT
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end
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type Chaocipher
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text L_ALPHABET ← "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
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text R_ALPHABET ← "PTLNBQDEOYSFAVZKGJRIHWXUMC"
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fun exec ← text by text value, Chaocipher:Mode mode, logic showSteps
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^|since texts are mutable, we can operate directly on them without the need of Lists|^
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text left ← *L_ALPHABET # by using the valueOf operator we are sure that the string is copied
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text right ← *R_ALPHABET
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text eText ← text(" ", value.length)
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text temp ← text(" ", 26)
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for int i ← 0; i < value.length; ++i
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if showSteps do writeLine(left + " " + right) end
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int index ← 0
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if mode æ Chaocipher:Mode.ENCRYPT
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index ← right.find(value[i])
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eText[i] ← left[index]
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else
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index ← left.find(value[i])
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eText[i] ← right[index]
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end
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if i æ value.length - 1 do break end
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# permute left
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for int j ← index; j < 26; ++j do temp[j - index] ← left[j] end
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for int j ← 0; j < index; ++j do temp[26 - index + j] ← left[j] end
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var store ← temp[1]
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for int j ← 2; j < 14; ++j do temp[j - 1] ← temp[j] end
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temp[13] ← store
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left ← *temp
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# permute right
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for int j ← index; j < 26; ++j do temp[j - index] ← right[j] end
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for int j ← 0; j < index; ++j do temp[26 - index + j] ← right[j] end
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store ← temp[0]
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for int j ← 1; j < 26; ++j do temp[j - 1] ← temp[j] end
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temp[25] ← store
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store ← temp[2]
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for int j ← 3; j < 14; ++j do temp[j - 1] ← temp[j] end
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temp[13] ← store
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right ← *temp
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end
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return eText
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end
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var plainText ← "WELLDONEISBETTERTHANWELLSAID"
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writeLine("The original plaintext is : ", plainText)
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writeLine(EOL, "The left and right alphabets after each permutation during encryption are :", EOL)
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var cipherText ← exec(plainText, Chaocipher:Mode.ENCRYPT, true)
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writeLine(EOL, "The ciphertext is : ", cipherText)
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var plainText2 ← exec(cipherText, Chaocipher:Mode.DECRYPT, false)
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writeLine(EOL, "The recovered plaintext is : ", plainText2)
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