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GeezerVison is showing github.com — Java/ciphers/ColumnarTranspositionCipher.java at master · mimibar/Java Expand file tree/ Copy pathColumnarTranspositionCipher.javaMore file actions 224 lines (210 loc) · 7.54 KB / Copy pathColumnarTranspositionCipher.javaFile metadata and controls224 lines (210 loc) · 7.54 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 package ciphers; /** * Columnar Transposition Cipher Encryption and Decryption. * * @author <a href="https://github.com/freitzzz">freitzzz</a> */ public class ColumnarTranspositionCipher { private static String keyword; private static Object[][] table; private static String abecedarium; public static final String ABECEDARIUM = "abcdefghijklmnopqrstuvwxyzABCDEFG" + "HIJKLMNOPQRSTUVWXYZ0123456789,.;:-@"; private static final String ENCRYPTION_FIELD = "≈"; private static final char ENCRYPTION_FIELD_CHAR = '≈'; /** * Encrypts a certain String with the Columnar Transposition Cipher Rule * * @param word Word being encrypted * @param keyword String with keyword being used * @return a String with the word encrypted by the Columnar Transposition * Cipher Rule */ public static String encrpyter(String word, String keyword) { ColumnarTranspositionCipher.keyword = keyword; abecedariumBuilder(500); table = tableBuilder(word); Object[][] sortedTable = sortTable(table); String wordEncrypted = ""; for (int i = 0; i < sortedTable[i].length; i++) { for (int j = 1; j < sortedTable.length; j++) { wordEncrypted += sortedTable[j][i]; } } return wordEncrypted; } /** * Encrypts a certain String with the Columnar Transposition Cipher Rule * * @param word Word being encrypted * @param keyword String with keyword being used * @param abecedarium String with the abecedarium being used. null for * default one * @return a String with the word encrypted by the Columnar Transposition * Cipher Rule */ public static String encrpyter(String word, String keyword, String abecedarium) { ColumnarTranspositionCipher.keyword = keyword; if (abecedarium != null) { ColumnarTranspositionCipher.abecedarium = abecedarium; } else { ColumnarTranspositionCipher.abecedarium = ABECEDARIUM; } table = tableBuilder(word); Object[][] sortedTable = sortTable(table); String wordEncrypted = ""; for (int i = 0; i < sortedTable[0].length; i++) { for (int j = 1; j < sortedTable.length; j++) { wordEncrypted += sortedTable[j][i]; } } return wordEncrypted; } /** * Decrypts a certain encrypted String with the Columnar Transposition * Cipher Rule * * @return a String decrypted with the word encrypted by the Columnar * Transposition Cipher Rule */ public static String decrypter() { String wordDecrypted = ""; for (int i = 1; i < table.length; i++) { for (Object item : table[i]) { wordDecrypted += item; } } return wordDecrypted.replaceAll(ENCRYPTION_FIELD, ""); } /** * Builds a table with the word to be encrypted in rows by the Columnar * Transposition Cipher Rule * * @return An Object[][] with the word to be encrypted filled in rows and * columns */ private static Object[][] tableBuilder(String word) { Object[][] table = new Object[numberOfRows(word) + 1][keyword.length()]; char[] wordInChards = word.toCharArray(); //Fils in the respective numbers table[0] = findElements(); int charElement = 0; for (int i = 1; i < table.length; i++) { for (int j = 0; j < table[i].length; j++) { if (charElement < wordInChards.length) { table[i][j] = wordInChards[charElement]; charElement++; } else { table[i][j] = ENCRYPTION_FIELD_CHAR; } } } return table; } /** * Determines the number of rows the table should have regarding the * Columnar Transposition Cipher Rule * * @return an int with the number of rows that the table should have in * order to respect the Columnar Transposition Cipher Rule. */ private static int numberOfRows(String word) { if ((double) word.length() / keyword.length() > word.length() / keyword.length()) { return (word.length() / keyword.length()) + 1; } else { return word.length() / keyword.length(); } } /** * * @return charValues */ private static Object[] findElements() { Object[] charValues = new Object[keyword.length()]; for (int i = 0; i < charValues.length; i++) { int charValueIndex = abecedarium.indexOf(keyword.charAt(i)); charValues[i] = charValueIndex > -1 ? charValueIndex : null; } return charValues; } /** * * @param table * @return tableSorted */ private static Object[][] sortTable(Object[][] table) { Object[][] tableSorted = new Object[table.length][table[0].length]; for (int i = 0; i < tableSorted.length; i++) { System.arraycopy(table[i], 0, tableSorted[i], 0, tableSorted[i].length); } for (int i = 0; i < tableSorted[0].length; i++) { for (int j = i + 1; j < tableSorted[0].length; j++) { if ((int) tableSorted[0][i] > (int) table[0][j]) { Object[] column = getColumn(tableSorted, tableSorted.length, i); switchColumns(tableSorted, j, i, column); } } } return tableSorted; } /** * * @param table * @param rows * @param column * @return columnArray */ private static Object[] getColumn(Object[][] table, int rows, int column) { Object[] columnArray = new Object[rows]; for (int i = 0; i < rows; i++) { columnArray[i] = table[i][column]; } return columnArray; } /** * * @param table * @param firstColumnIndex * @param secondColumnIndex * @param columnToSwitch */ private static void switchColumns(Object[][] table, int firstColumnIndex, int secondColumnIndex, Object[] columnToSwitch) { for (int i = 0; i < table.length; i++) { table[i][secondColumnIndex] = table[i][firstColumnIndex]; table[i][firstColumnIndex] = columnToSwitch[i]; } } /** * Creates an abecedarium with a specified ascii inded * * @param value Number of characters being used based on the ASCII Table */ private static void abecedariumBuilder(int value) { abecedarium = ""; for (int i = 0; i < value; i++) { abecedarium += (char) i; } } private static void showTable() { for (Object[] table1 : table) { for (Object item : table1) { System.out.print(item + " "); } System.out.println(); } } public static void main(String[] args) { String keywordForExample = "asd215"; String wordBeingEncrypted = "This is a test of the Columnar Transposition Cipher"; System.out.println("### Example of Columnar Transposition Cipher ###\n"); System.out.println("Word being encryped ->>> " + wordBeingEncrypted); System.out.println("Word encrypted ->>> " + ColumnarTranspositionCipher .encrpyter(wordBeingEncrypted, keywordForExample)); System.out.println("Word decryped ->>> " + ColumnarTranspositionCipher .decrypter()); System.out.println("\n### Encrypted Table ###"); showTable(); } } |
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