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Add cipher class, cipher tests, enhance docs in 'AtbashCipher.java' (#5690)
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@ -50,6 +50,7 @@
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* [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
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* [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
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* [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
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* [AtbashCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
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* [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
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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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@ -663,6 +664,7 @@
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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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* [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
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* [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
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* [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashTest.java)
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* [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.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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71
src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
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71
src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
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package com.thealgorithms.ciphers;
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/**
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* The Atbash cipher is a simple substitution cipher that replaces each letter
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* in the alphabet with its reverse.
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* For example, 'A' becomes 'Z', 'B' becomes 'Y', and so on. It works
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* identically for both uppercase and lowercase letters.
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* It's a symmetric cipher, meaning applying it twice returns the original text.
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* Hence, the encrypting and the decrypting functions are identical
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* @author https://github.com/Krounosity
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* Learn more: https://en.wikipedia.org/wiki/Atbash
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*/
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public class AtbashCipher {
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private String toConvert;
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// Default constructor.
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AtbashCipher() {
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}
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// String setting constructor.
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AtbashCipher(String str) {
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toConvert = str;
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}
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// String getter method.
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public String getString() {
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return toConvert;
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}
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// String setter method.
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public void setString(String str) {
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toConvert = str;
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}
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// Checking whether the current character is capital.
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private boolean isCapital(char ch) {
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return ch >= 'A' && ch <= 'Z';
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}
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// Checking whether the current character is smallcased.
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private boolean isSmall(char ch) {
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return ch >= 'a' && ch <= 'z';
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}
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// Converting text to atbash cipher code or vice versa.
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public String convert() {
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// Using StringBuilder to store new string.
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StringBuilder convertedString = new StringBuilder();
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// Iterating for each character.
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for (char ch : toConvert.toCharArray()) {
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// If the character is smallcased.
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if (isSmall(ch)) {
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convertedString.append((char) ('z' - (ch - 'a')));
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}
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// If the character is capital cased.
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else if (isCapital(ch)) {
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convertedString.append((char) ('Z' - (ch - 'A')));
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}
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// Non-alphabetical character.
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else {
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convertedString.append(ch);
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}
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}
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return convertedString.toString();
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}
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}
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28
src/test/java/com/thealgorithms/ciphers/AtbashTest.java
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src/test/java/com/thealgorithms/ciphers/AtbashTest.java
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package com.thealgorithms.ciphers;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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import org.junit.jupiter.api.Test;
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public class AtbashTest {
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@Test
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public void atbashEncrypt() {
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AtbashCipher normalToEncrypt = new AtbashCipher("Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!");
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String expectedText = "Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!";
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normalToEncrypt.setString(normalToEncrypt.convert());
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assertEquals(expectedText, normalToEncrypt.getString());
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}
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@Test
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public void atbashDecrypt() {
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AtbashCipher encryptToNormal = new AtbashCipher("Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!");
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String expectedText = "Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!";
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encryptToNormal.setString(encryptToNormal.convert());
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assertEquals(expectedText, encryptToNormal.getString());
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}
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}
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