Des (#4172)
* Update directory
* Add DES Encryption algorithm
* Update directory
---------
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
This commit is contained in:
Aditya Pal
GitHub
parent
db9c78a598
commit
19bd2408ff
18
DIRECTORY.md
18
DIRECTORY.md
@ -30,6 +30,7 @@
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* [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
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* [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
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* [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
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* [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java)
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* [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java)
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* [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
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* [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
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@ -151,14 +152,15 @@
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* [AVLSimple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java)
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* [AVLTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java)
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* [BinaryTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java)
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* [BSTFromSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java)
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* [BSTIterative](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTIterative.java)
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* [BSTRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java)
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* [BSTRecursiveGeneric](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java)
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* [CeilInBinarySearchTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java)
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* [CheckBinaryTreeIsValidBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java)
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* [CheckIfBinaryTreeBalanced](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java)
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* [CheckTreeIsSymmetric](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java)
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* [CreateBinaryTreeFromInorderPreorder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java)
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* [CreateBSTFromSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CreateBSTFromSortedArray.java)
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* [FenwickTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java)
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* [GenericTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java)
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* [InorderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java)
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@ -166,7 +168,6 @@
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* [LazySegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java)
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* [LCA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LCA.java)
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* [LevelOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java)
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* [LevelOrderTraversalHelper](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversalHelper.java)
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* [nearestRightKey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java)
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* [PostOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java)
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* [PreOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java)
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@ -175,9 +176,7 @@
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* [SameTreesCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
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* [SegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
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* [TreeRandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
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* [TreeTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeTraversal.java)
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* [TrieImp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java)
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* [ValidBSTOrNot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/ValidBSTOrNot.java)
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* [VerticalOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
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* [ZigzagTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java)
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* devutils
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@ -202,6 +201,7 @@
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* [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
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* [BruteForceKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java)
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* [CatalanNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java)
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* [ClimbingStairs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java)
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* [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java)
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* [CountFriendsPairing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java)
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* [DiceThrow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java)
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@ -382,6 +382,7 @@
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* [KochSnowflake](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/KochSnowflake.java)
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* [Krishnamurthy](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Krishnamurthy.java)
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* [LinearCongruentialGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java)
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* [LineSweep](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LineSweep.java)
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* [LowestBasePalindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
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* [Luhn](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Luhn.java)
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* [Mandelbrot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Mandelbrot.java)
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@ -403,7 +404,6 @@
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* [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StackPostfixNotation.java)
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* [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
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* [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
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* [ThreeSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ThreeSum.java)
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* [TopKWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TopKWords.java)
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* [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
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* [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
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@ -526,6 +526,7 @@
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* [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
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* [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
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* [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
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* [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
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* [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
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* [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
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* [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
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@ -575,7 +576,10 @@
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* [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
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* trees
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* [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
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* [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
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* [BSTIterativeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
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* [CeilInBinarySearchTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTreeTest.java)
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* [CheckBinaryTreeIsValidBSTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java)
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* [CheckTreeIsSymmetricTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetricTest.java)
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* [InorderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/InorderTraversalTest.java)
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* [KDTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java)
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@ -585,7 +589,6 @@
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* [PreOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
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* [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
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* [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
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* [ValidBSTOrNotTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ValidBSTOrNotTest.java)
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* [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
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* [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
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* divideandconquer
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@ -593,6 +596,7 @@
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* [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
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* dynamicprogramming
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* [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
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* [climbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java)
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* [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
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* [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
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* [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
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@ -674,6 +678,7 @@
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* [CRCAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
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* [FirstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
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* [KadaneAlogrithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java)
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* [LineSweepTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LineSweepTest.java)
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* [LinkListSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LinkListSortTest.java)
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* [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
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* [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
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@ -731,6 +736,7 @@
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* [CheckAnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java)
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* [CheckVowelsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
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* [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
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* [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
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* [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
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* [LetterCombinationsOfPhoneNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
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* [longestNonRepeativeSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/longestNonRepeativeSubstringTest.java)
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344
src/main/java/com/thealgorithms/ciphers/DES.java
Normal file
344
src/main/java/com/thealgorithms/ciphers/DES.java
Normal file
@ -0,0 +1,344 @@
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package com.thealgorithms.ciphers;
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/**
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* This class is build to demonstrate the application of the DES-algorithm on a
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* plain English message. The supplied key must be in form of a 64 bit binary String.
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*/
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public class DES {
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private String key;
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private String subKeys[];
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private void sanitize(String key) {
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int length = key.length();
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if (length != 64) {
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throw new IllegalArgumentException("DES key must be supplied as a 64 character binary string");
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}
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}
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DES(String key) {
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sanitize(key);
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this.key = key;
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subKeys = getSubkeys(key);
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}
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public String getKey() {
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return this.key;
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}
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public void setKey(String key) {
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sanitize(key);
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this.key = key;
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}
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//Permutation table to convert initial 64 bit key to 56 bit key
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private static int[] PC1 =
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{
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57, 49, 41, 33, 25, 17, 9,
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1, 58, 50, 42, 34, 26, 18,
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10, 2, 59, 51, 43, 35, 27,
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19, 11, 3, 60, 52, 44, 36,
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63, 55, 47, 39, 31, 23, 15,
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7, 62, 54, 46, 38, 30, 22,
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14, 6, 61, 53, 45, 37, 29,
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21, 13, 5, 28, 20, 12, 4
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};
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//Lookup table used to shift the initial key, in order to generate the subkeys
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private static int[] KEY_SHIFTS =
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{
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1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
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};
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//Table to convert the 56 bit subkeys to 48 bit subkeys
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private static int[] PC2 =
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{
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14, 17, 11, 24, 1, 5,
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3, 28, 15, 6, 21, 10,
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23, 19, 12, 4, 26, 8,
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16, 7, 27, 20, 13, 2,
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41, 52, 31, 37, 47, 55,
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30, 40, 51, 45, 33, 48,
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44, 49, 39, 56, 34, 53,
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46, 42, 50, 36, 29, 32
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};
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//Initial permutatation of each 64 but message block
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private static int[] IP =
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{
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58, 50, 42, 34, 26, 18, 10 , 2,
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60, 52, 44, 36, 28, 20, 12, 4,
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62, 54, 46, 38, 30, 22, 14, 6,
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64, 56, 48, 40, 32, 24, 16, 8,
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57, 49, 41, 33, 25, 17, 9, 1,
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59, 51, 43, 35, 27, 19, 11, 3,
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61, 53, 45, 37, 29, 21, 13, 5,
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63, 55, 47, 39, 31, 23, 15, 7
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};
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//Expansion table to convert right half of message blocks from 32 bits to 48 bits
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private static int[] expansion =
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{
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32, 1, 2, 3, 4, 5,
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4, 5, 6, 7, 8, 9,
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8, 9, 10, 11, 12, 13,
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12, 13, 14, 15, 16, 17,
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16, 17, 18, 19, 20, 21,
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20, 21, 22, 23, 24, 25,
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24, 25, 26, 27, 28, 29,
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28, 29, 30, 31, 32, 1
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};
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//The eight substitution boxes are defined below
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private static int[][] s1 = {
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{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
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{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
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{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
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{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}
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};
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private static int[][] s2 = {
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{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
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{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
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{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
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{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}
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};
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private static int[][] s3 = {
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{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
|
||||
{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
|
||||
{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
|
||||
{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}
|
||||
};
|
||||
|
||||
private static int[][] s4 = {
|
||||
{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
|
||||
{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
|
||||
{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
|
||||
{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}
|
||||
};
|
||||
|
||||
private static int[][] s5 = {
|
||||
{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
|
||||
{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
|
||||
{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
|
||||
{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}
|
||||
};
|
||||
|
||||
private static int[][] s6 = {
|
||||
{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
|
||||
{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
|
||||
{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
|
||||
{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}
|
||||
};
|
||||
|
||||
private static int[][] s7 = {
|
||||
{4, 11, 2, 14, 15, 0, 8, 13 , 3, 12, 9 , 7, 5, 10, 6, 1},
|
||||
{13 , 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
|
||||
{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
|
||||
{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}
|
||||
};
|
||||
|
||||
private static int[][] s8 = {
|
||||
{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
|
||||
{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6 ,11, 0, 14, 9, 2},
|
||||
{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10 ,13, 15, 3, 5, 8},
|
||||
{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6 ,11}
|
||||
};
|
||||
|
||||
private static int[][][] s = {s1, s2, s3, s4, s5, s6, s7, s8};
|
||||
|
||||
//Permutation table, used in the feistel function post s-box usage
|
||||
static int[] permutation =
|
||||
{
|
||||
16, 7, 20, 21,
|
||||
29, 12, 28, 17,
|
||||
1, 15, 23, 26,
|
||||
5, 18, 31, 10,
|
||||
2, 8, 24, 14,
|
||||
32, 27, 3, 9,
|
||||
19, 13, 30, 6,
|
||||
22, 11, 4, 25
|
||||
};
|
||||
|
||||
//Table used for final inversion of the message box after 16 rounds of Feistel Function
|
||||
static int[] IPinverse =
|
||||
{
|
||||
40, 8, 48, 16, 56, 24, 64, 32,
|
||||
39, 7, 47, 15, 55, 23, 63, 31,
|
||||
38, 6, 46, 14, 54, 22, 62, 30,
|
||||
37, 5, 45, 13, 53, 21, 61, 29,
|
||||
36, 4, 44, 12, 52, 20, 60, 28,
|
||||
35, 3, 43 ,11, 51, 19, 59, 27,
|
||||
34, 2, 42, 10, 50, 18, 58, 26,
|
||||
33, 1, 41, 9, 49, 17, 57, 25
|
||||
};
|
||||
|
||||
private String[] getSubkeys(String originalKey) {
|
||||
StringBuilder permutedKey = new StringBuilder(); //Initial permutation of keys via PC1
|
||||
int i, j;
|
||||
for (i = 0; i < 56; i++) {
|
||||
permutedKey.append(originalKey.charAt(PC1[i] - 1));
|
||||
}
|
||||
String subKeys[] = new String[16];
|
||||
String initialPermutedKey = permutedKey.toString();
|
||||
String C0 = initialPermutedKey.substring(0, 28), D0 = initialPermutedKey.substring(28);
|
||||
|
||||
//We will now operate on the left and right halves of the permutedKey
|
||||
for (i = 0; i < 16; i++) {
|
||||
String Cn = C0.substring(KEY_SHIFTS[i]) + C0.substring(0, KEY_SHIFTS[i]);
|
||||
String Dn = D0.substring(KEY_SHIFTS[i]) + D0.substring(0, KEY_SHIFTS[i]);
|
||||
subKeys[i] = Cn + Dn;
|
||||
C0 = Cn; //Re-assign the values to create running permutation
|
||||
D0 = Dn;
|
||||
}
|
||||
|
||||
//Let us shrink the keys to 48 bits (well, characters here) using PC2
|
||||
for (i = 0; i < 16; i++) {
|
||||
String key = subKeys[i];
|
||||
permutedKey.setLength(0);
|
||||
for (j = 0; j < 48; j++) {
|
||||
permutedKey.append(key.charAt(PC2[j] - 1));
|
||||
}
|
||||
subKeys[i] = permutedKey.toString();
|
||||
}
|
||||
|
||||
return subKeys;
|
||||
}
|
||||
|
||||
private String XOR(String a, String b) {
|
||||
int i, l = a.length();
|
||||
StringBuilder xor = new StringBuilder();
|
||||
for (i = 0; i < l; i++) {
|
||||
int firstBit = a.charAt(i) - 48; // 48 is '0' in ascii
|
||||
int secondBit = b.charAt(i) - 48;
|
||||
xor.append((firstBit ^ secondBit));
|
||||
}
|
||||
return xor.toString();
|
||||
}
|
||||
|
||||
private String createPaddedString(String s, int desiredLength, char pad) {
|
||||
int i, l = s.length();
|
||||
StringBuilder paddedString = new StringBuilder();
|
||||
int diff = desiredLength - l;
|
||||
for (i = 0; i < diff; i++) {
|
||||
paddedString.append(pad);
|
||||
}
|
||||
return paddedString.toString();
|
||||
}
|
||||
|
||||
private String pad(String s, int desiredLength) {
|
||||
return createPaddedString(s, desiredLength, '0') + s;
|
||||
}
|
||||
|
||||
private String padLast(String s, int desiredLength) {
|
||||
return s + createPaddedString(s, desiredLength, '\u0000');
|
||||
}
|
||||
|
||||
private String feistel(String messageBlock, String key) {
|
||||
int i;
|
||||
StringBuilder expandedKey = new StringBuilder();
|
||||
for (i = 0; i < 48; i++) {
|
||||
expandedKey.append(messageBlock.charAt(expansion[i] - 1));
|
||||
}
|
||||
String mixedKey = XOR(expandedKey.toString(), key);
|
||||
StringBuilder substitutedString = new StringBuilder();
|
||||
|
||||
//Let us now use the s-boxes to transform each 6 bit (length here) block to 4 bits
|
||||
for (i = 0; i < 48; i += 6) {
|
||||
String block = mixedKey.substring(i, i + 6);
|
||||
int row = (block.charAt(0) - 48) * 2 + (block.charAt(5) - 48);
|
||||
int col = (block.charAt(1) - 48) * 8 + (block.charAt(2) - 48) * 4 + (block.charAt(3) - 48) * 2 + (block.charAt(4) - 48);
|
||||
String substitutedBlock = pad(Integer.toBinaryString(s[i / 6][row][col]), 4);
|
||||
substitutedString.append(substitutedBlock);
|
||||
}
|
||||
|
||||
StringBuilder permutedString = new StringBuilder();
|
||||
for (i = 0; i < 32; i++) {
|
||||
permutedString.append(substitutedString.charAt(permutation[i] - 1));
|
||||
}
|
||||
|
||||
return permutedString.toString();
|
||||
}
|
||||
|
||||
private String encryptBlock(String message, String keys[]) {
|
||||
StringBuilder permutedMessage = new StringBuilder();
|
||||
int i;
|
||||
for (i = 0; i < 64; i++) {
|
||||
permutedMessage.append(message.charAt(IP[i] - 1));
|
||||
}
|
||||
String L0 = permutedMessage.substring(0, 32), R0 = permutedMessage.substring(32);
|
||||
|
||||
//Iterate 16 times
|
||||
for (i = 0; i < 16; i++) {
|
||||
String Ln = R0; // Previous Right block
|
||||
String Rn = XOR(L0, feistel(R0, keys[i]));
|
||||
L0 = Ln;
|
||||
R0 = Rn;
|
||||
}
|
||||
|
||||
String combinedBlock = R0 + L0; //Reverse the 16th block
|
||||
permutedMessage.setLength(0);
|
||||
for (i = 0; i < 64; i++) {
|
||||
permutedMessage.append(combinedBlock.charAt(IPinverse[i] - 1));
|
||||
}
|
||||
return permutedMessage.toString();
|
||||
}
|
||||
|
||||
//To decode, we follow the same process as encoding, but with reversed keys
|
||||
private String decryptBlock(String message, String keys[]) {
|
||||
String reversedKeys[] = new String[keys.length];
|
||||
for (int i = 0; i < keys.length; i++) {
|
||||
reversedKeys[i] = keys[keys.length - i - 1];
|
||||
}
|
||||
return encryptBlock(message, reversedKeys);
|
||||
}
|
||||
|
||||
/**
|
||||
* @param message Message to be encrypted
|
||||
* @return The encrypted message, as a binary string
|
||||
*/
|
||||
public String encrypt(String message) {
|
||||
StringBuilder encryptedMessage = new StringBuilder();
|
||||
int l = message.length(), i, j;
|
||||
if (l % 8 != 0) {
|
||||
int desiredLength = (l / 8 + 1) * 8;
|
||||
l = desiredLength;
|
||||
message = padLast(message, desiredLength);
|
||||
}
|
||||
|
||||
for (i = 0; i < l; i+= 8) {
|
||||
String block = message.substring(i, i + 8);
|
||||
StringBuilder bitBlock = new StringBuilder();
|
||||
byte[] bytes = block.getBytes();
|
||||
for (j = 0; j < 8; j++) {
|
||||
bitBlock.append(pad(Integer.toBinaryString(bytes[j]), 8));
|
||||
}
|
||||
encryptedMessage.append(encryptBlock(bitBlock.toString(), subKeys));
|
||||
}
|
||||
return encryptedMessage.toString();
|
||||
}
|
||||
|
||||
/**
|
||||
* @param message The encrypted string. Expects it to be a multiple of 64 bits, in binary format
|
||||
* @return The decrypted String, in plain English
|
||||
*/
|
||||
public String decrypt(String message) {
|
||||
StringBuilder decryptedMessage = new StringBuilder();
|
||||
int l = message.length(), i, j;
|
||||
if (l % 64 != 0) {
|
||||
throw new IllegalArgumentException("Encrypted message should be a multiple of 64 characters in length");
|
||||
}
|
||||
for (i = 0; i < l; i+= 64) {
|
||||
String block = message.substring(i, i + 64);
|
||||
String result = decryptBlock(block.toString(), subKeys);
|
||||
byte res[] = new byte[8];
|
||||
for (j = 0; j < 64; j+=8) {
|
||||
res[j / 8] = (byte)Integer.parseInt(result.substring(j, j + 8), 2);
|
||||
}
|
||||
decryptedMessage.append(new String(res));
|
||||
}
|
||||
return decryptedMessage.toString().replace("\0", ""); // Get rid of the null bytes used for padding
|
||||
}
|
||||
|
||||
}
|
||||
51
src/test/java/com/thealgorithms/ciphers/DESTest.java
Normal file
51
src/test/java/com/thealgorithms/ciphers/DESTest.java
Normal file
@ -0,0 +1,51 @@
|
||||
package com.thealgorithms.ciphers;
|
||||
|
||||
import static org.junit.jupiter.api.Assertions.*;
|
||||
|
||||
import org.junit.jupiter.api.BeforeEach;
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
//Test example taken from https://page.math.tu-berlin.de/~kant/teaching/hess/krypto-ws2006/des.htm
|
||||
public class DESTest {
|
||||
|
||||
DES des;
|
||||
|
||||
@BeforeEach
|
||||
public void setUp() {
|
||||
des = new DES("0000111000110010100100100011001011101010011011010000110101110011");
|
||||
}
|
||||
|
||||
@Test
|
||||
void testEncrypt() {
|
||||
//given
|
||||
String plainText = "Your lips are smoother than vaseline\r\n";
|
||||
//This is equal to c0999fdde378d7ed727da00bca5a84ee47f269a4d6438190d9d52f78f5358499828ac9b453e0e653 in hexadecimal
|
||||
String expectedOutput = "11000000100110011001111111011101111000110111100011010111111" +
|
||||
"011010111001001111101101000000000101111001010010110101000010011101110010001111111001" +
|
||||
"001101001101001001101011001000011100000011001000011011001110101010010111101111000111" +
|
||||
"101010011010110000100100110011000001010001010110010011011010001010011111000001110011001010011";
|
||||
|
||||
//when
|
||||
String cipherText = des.encrypt(plainText);
|
||||
|
||||
//then
|
||||
assertEquals(expectedOutput, cipherText);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testDecrypt() {
|
||||
//given
|
||||
//This is equal to c0999fdde378d7ed727da00bca5a84ee47f269a4d6438190d9d52f78f5358499828ac9b453e0e653 in hexadecimal
|
||||
String cipherText = "11000000100110011001111111011101111000110111100011010111111" +
|
||||
"011010111001001111101101000000000101111001010010110101000010011101110010001111111001" +
|
||||
"001101001101001001101011001000011100000011001000011011001110101010010111101111000111" +
|
||||
"101010011010110000100100110011000001010001010110010011011010001010011111000001110011001010011";
|
||||
String expectedOutput = "Your lips are smoother than vaseline\r\n";;
|
||||
|
||||
//when
|
||||
String plainText = des.decrypt(cipherText);
|
||||
|
||||
//then
|
||||
assertEquals(expectedOutput, plainText);
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user