From b77076b0aac8bc913d1e8c69165e0b7ee3e50edc Mon Sep 17 00:00:00 2001 From: Govind Gupta <202152312@iiitvadodara.ac.in> Date: Tue, 2 Jan 2024 22:14:36 +0530 Subject: [PATCH 1/5] Added Playfair Cipher --- .../thealgorithms/ciphers/PlayfairCipher.java | 151 ++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java diff --git a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java new file mode 100644 index 000000000000..1a1896397bb5 --- /dev/null +++ b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java @@ -0,0 +1,151 @@ +import java.util.Scanner; + +public class PlayfairCipher { + + private char[][] matrix; + private String key; + + public PlayfairCipher(String key) { + this.key = key; + generateMatrix(); + } + + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + + System.out.print("\nEnter the key: "); + String key = sc.nextLine(); + + System.out.print("\nEnter the plaintext: "); + String plaintext = sc.nextLine(); + + PlayfairCipher cipher = new PlayfairCipher(key); + cipher.printMatrix(); + + // Encryption + String encryptedText = cipher.encrypt(plaintext); + System.out.println("\nPlaintext: " + plaintext); + System.out.println("\nEncrypted Text: " + encryptedText); + + // Decryption + String decryptedText = cipher.decrypt(encryptedText); + System.out.println("\nDecrypted Text: " + decryptedText); + } + + private void generateMatrix() { + String keyWithoutDuplicates = removeDuplicateChars(key + "ABCDEFGHIKLMNOPQRSTUVWXYZ"); + matrix = new char[5][5]; + int index = 0; + for (int i = 0; i < 5; i++) { + for (int j = 0; j < 5; j++) { + matrix[i][j] = keyWithoutDuplicates.charAt(index); + index++; + } + } + } + + private String removeDuplicateChars(String str) { + StringBuilder result = new StringBuilder(); + for (int i = 0; i < str.length(); i++) { + if (result.indexOf(String.valueOf(str.charAt(i))) == -1) { + result.append(str.charAt(i)); + } + } + return result.toString(); + } + + public String encrypt(String plaintext) { + plaintext = prepareText(plaintext.replace("J", "I")); + StringBuilder ciphertext = new StringBuilder(); + for (int i = 0; i < plaintext.length(); i += 2) { + char char1 = plaintext.charAt(i); + char char2 = plaintext.charAt(i + 1); + int[] pos1 = findPosition(char1); + int[] pos2 = findPosition(char2); + int row1 = pos1[0]; + int col1 = pos1[1]; + int row2 = pos2[0]; + int col2 = pos2[1]; + if (row1 == row2) { + ciphertext.append(matrix[row1][(col1 + 1) % 5]); + ciphertext.append(matrix[row2][(col2 + 1) % 5]); + } else if (col1 == col2) { + ciphertext.append(matrix[(row1 + 1) % 5][col1]); + ciphertext.append(matrix[(row2 + 1) % 5][col2]); + } else { + ciphertext.append(matrix[row1][col2]); + ciphertext.append(matrix[row2][col1]); + } + } + return ciphertext.toString(); + } + + public String decrypt(String ciphertext) { + StringBuilder plaintext = new StringBuilder(); + for (int i = 0; i < ciphertext.length(); i += 2) { + char char1 = ciphertext.charAt(i); + char char2 = ciphertext.charAt(i + 1); + int[] pos1 = findPosition(char1); + int[] pos2 = findPosition(char2); + int row1 = pos1[0]; + int col1 = pos1[1]; + int row2 = pos2[0]; + int col2 = pos2[1]; + if (row1 == row2) { + plaintext.append(matrix[row1][(col1 + 4) % 5]); + plaintext.append(matrix[row2][(col2 + 4) % 5]); + } else if (col1 == col2) { + plaintext.append(matrix[(row1 + 4) % 5][col1]); + plaintext.append(matrix[(row2 + 4) % 5][col2]); + } else { + plaintext.append(matrix[row1][col2]); + plaintext.append(matrix[row2][col1]); + } + } + return plaintext.toString(); + } + + private String prepareText(String text) { + text = text.toUpperCase().replaceAll("[^A-Z]", ""); + StringBuilder preparedText = new StringBuilder(); + char prevChar = '\0'; + for (char c : text.toCharArray()) { + if (c != prevChar) { + preparedText.append(c); + prevChar = c; + } else { + preparedText.append('X').append(c); + prevChar = '\0'; + } + } + if (preparedText.length() % 2 != 0) { + preparedText.append('X'); + } + System.out.println("\nPrepared Text : " + preparedText.toString()); + return preparedText.toString(); + } + + private int[] findPosition(char c) { + int[] pos = new int[2]; + for (int i = 0; i < 5; i++) { + for (int j = 0; j < 5; j++) { + if (matrix[i][j] == c) { + pos[0] = i; + pos[1] = j; + return pos; + } + } + } + return pos; + } + + public void printMatrix() { + System.out.println("\nPlayfair Cipher Matrix:"); + for (int i = 0; i < 5; i++) { + for (int j = 0; j < 5; j++) { + System.out.print(matrix[i][j] + " "); + } + System.out.println(); + } + } +} From 434f3cfe05d40b5282e696582ebc70ed5b1c19dc Mon Sep 17 00:00:00 2001 From: Govind Gupta <202152312@iiitvadodara.ac.in> Date: Wed, 3 Jan 2024 00:06:05 +0530 Subject: [PATCH 2/5] Added JUnit Test --- .../thealgorithms/ciphers/PlayfairCipher.java | 2 + .../thealgorithms/ciphers/PlayfairTest.java | 37 +++++++++++++++++++ 2 files changed, 39 insertions(+) create mode 100644 src/test/java/com/thealgorithms/ciphers/PlayfairTest.java diff --git a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java index 1a1896397bb5..970030ea6770 100644 --- a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java +++ b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java @@ -1,3 +1,5 @@ +package com.thealgorithms.ciphers; + import java.util.Scanner; public class PlayfairCipher { diff --git a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java new file mode 100644 index 000000000000..2dc01f719bb9 --- /dev/null +++ b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java @@ -0,0 +1,37 @@ +package com.thealgorithms.ciphers; + +import org.junit.jupiter.api.Test; +import static org.junit.jupiter.api.Assertions.*; + +public class PlayfairTest { + + @Test + public void testEncryption() { + PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); + + String plaintext = "HELLO"; + String encryptedText = playfairCipher.encrypt(plaintext); + assertEquals("GYIZSC", encryptedText); + } + + @Test + public void testDecryption() { + PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); + + String encryptedText = "UDRIYP"; + String decryptedText = playfairCipher.decrypt(encryptedText); + assertEquals("NEBFVH", decryptedText); + } + + @Test + public void testEncryptionAndDecryption() { + PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); + + String plaintext = "PLAYFAIR"; + String encryptedText = playfairCipher.encrypt(plaintext); + String decryptedText = playfairCipher.decrypt(encryptedText); + + assertEquals(plaintext, decryptedText); + } + +} From b7b79b26f98551e6fd6a9d64909e7433c0483e76 Mon Sep 17 00:00:00 2001 From: Govind Gupta <202152312@iiitvadodara.ac.in> Date: Wed, 3 Jan 2024 00:11:14 +0530 Subject: [PATCH 3/5] Added JUnit Test --- src/test/java/com/thealgorithms/ciphers/PlayfairTest.java | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java index 2dc01f719bb9..da00d7bf03d6 100644 --- a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java +++ b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java @@ -1,8 +1,9 @@ package com.thealgorithms.ciphers; -import org.junit.jupiter.api.Test; import static org.junit.jupiter.api.Assertions.*; +import org.junit.jupiter.api.Test; + public class PlayfairTest { @Test From bcf94a70f47a877924071e0f30745821f78d856f Mon Sep 17 00:00:00 2001 From: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Date: Tue, 2 Jan 2024 18:59:59 +0000 Subject: [PATCH 4/5] Update directory --- DIRECTORY.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/DIRECTORY.md b/DIRECTORY.md index fd50b2914cff..b621216da7f1 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -27,6 +27,7 @@ * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java) * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java) * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java) + * [SetKthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java) * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java) * ciphers * a5 @@ -44,6 +45,7 @@ * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java) * [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java) * [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java) + * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java) * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java) * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java) * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java) @@ -585,6 +587,7 @@ * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java) * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java) * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java) + * [SetKthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java) * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java) * ciphers * a5 @@ -592,6 +595,7 @@ * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java) * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java) * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java) + * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java) * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java) * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java) * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java) From 34f9af6371671e1a8a4a7d669d9ead7183494fce Mon Sep 17 00:00:00 2001 From: Govind Gupta <202152312@iiitvadodara.ac.in> Date: Wed, 3 Jan 2024 10:02:36 +0530 Subject: [PATCH 5/5] modified format --- .../thealgorithms/ciphers/PlayfairCipher.java | 69 ++++++------------- .../thealgorithms/ciphers/PlayfairTest.java | 9 ++- 2 files changed, 26 insertions(+), 52 deletions(-) diff --git a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java index 970030ea6770..76ceb6dbce31 100644 --- a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java +++ b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java @@ -1,7 +1,5 @@ package com.thealgorithms.ciphers; -import java.util.Scanner; - public class PlayfairCipher { private char[][] matrix; @@ -12,50 +10,6 @@ public PlayfairCipher(String key) { generateMatrix(); } - public static void main(String[] args) { - Scanner sc = new Scanner(System.in); - - System.out.print("\nEnter the key: "); - String key = sc.nextLine(); - - System.out.print("\nEnter the plaintext: "); - String plaintext = sc.nextLine(); - - PlayfairCipher cipher = new PlayfairCipher(key); - cipher.printMatrix(); - - // Encryption - String encryptedText = cipher.encrypt(plaintext); - System.out.println("\nPlaintext: " + plaintext); - System.out.println("\nEncrypted Text: " + encryptedText); - - // Decryption - String decryptedText = cipher.decrypt(encryptedText); - System.out.println("\nDecrypted Text: " + decryptedText); - } - - private void generateMatrix() { - String keyWithoutDuplicates = removeDuplicateChars(key + "ABCDEFGHIKLMNOPQRSTUVWXYZ"); - matrix = new char[5][5]; - int index = 0; - for (int i = 0; i < 5; i++) { - for (int j = 0; j < 5; j++) { - matrix[i][j] = keyWithoutDuplicates.charAt(index); - index++; - } - } - } - - private String removeDuplicateChars(String str) { - StringBuilder result = new StringBuilder(); - for (int i = 0; i < str.length(); i++) { - if (result.indexOf(String.valueOf(str.charAt(i))) == -1) { - result.append(str.charAt(i)); - } - } - return result.toString(); - } - public String encrypt(String plaintext) { plaintext = prepareText(plaintext.replace("J", "I")); StringBuilder ciphertext = new StringBuilder(); @@ -107,6 +61,28 @@ public String decrypt(String ciphertext) { return plaintext.toString(); } + private void generateMatrix() { + String keyWithoutDuplicates = removeDuplicateChars(key + "ABCDEFGHIKLMNOPQRSTUVWXYZ"); + matrix = new char[5][5]; + int index = 0; + for (int i = 0; i < 5; i++) { + for (int j = 0; j < 5; j++) { + matrix[i][j] = keyWithoutDuplicates.charAt(index); + index++; + } + } + } + + private String removeDuplicateChars(String str) { + StringBuilder result = new StringBuilder(); + for (int i = 0; i < str.length(); i++) { + if (result.indexOf(String.valueOf(str.charAt(i))) == -1) { + result.append(str.charAt(i)); + } + } + return result.toString(); + } + private String prepareText(String text) { text = text.toUpperCase().replaceAll("[^A-Z]", ""); StringBuilder preparedText = new StringBuilder(); @@ -123,7 +99,6 @@ private String prepareText(String text) { if (preparedText.length() % 2 != 0) { preparedText.append('X'); } - System.out.println("\nPrepared Text : " + preparedText.toString()); return preparedText.toString(); } diff --git a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java index da00d7bf03d6..5562241b48db 100644 --- a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java +++ b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java @@ -9,7 +9,7 @@ public class PlayfairTest { @Test public void testEncryption() { PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); - + String plaintext = "HELLO"; String encryptedText = playfairCipher.encrypt(plaintext); assertEquals("GYIZSC", encryptedText); @@ -18,7 +18,7 @@ public void testEncryption() { @Test public void testDecryption() { PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); - + String encryptedText = "UDRIYP"; String decryptedText = playfairCipher.decrypt(encryptedText); assertEquals("NEBFVH", decryptedText); @@ -27,12 +27,11 @@ public void testDecryption() { @Test public void testEncryptionAndDecryption() { PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD"); - + String plaintext = "PLAYFAIR"; String encryptedText = playfairCipher.encrypt(plaintext); String decryptedText = playfairCipher.decrypt(encryptedText); - + assertEquals(plaintext, decryptedText); } - } pFad - Phonifier reborn

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