Add cipher class, cipher tests, enhance docs in 'AtbashCipher.java' (#5690)

This commit is contained in:
Varnan Rathod
2024-10-11 11:35:26 +05:30
committed by GitHub
parent 2040df88d9
commit 2338428578
3 changed files with 101 additions and 0 deletions

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@ -50,6 +50,7 @@
* [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java) * [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
* [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java) * [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
* [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java) * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
* [AtbashCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
* [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java) * [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
* [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java) * [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
* [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java) * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
@ -663,6 +664,7 @@
* [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java) * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
* [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java) * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
* [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java) * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
* [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashTest.java)
* [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java) * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
* [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java) * [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) * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)

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package com.thealgorithms.ciphers;
/**
* The Atbash cipher is a simple substitution cipher that replaces each letter
* in the alphabet with its reverse.
* For example, 'A' becomes 'Z', 'B' becomes 'Y', and so on. It works
* identically for both uppercase and lowercase letters.
* It's a symmetric cipher, meaning applying it twice returns the original text.
* Hence, the encrypting and the decrypting functions are identical
* @author https://github.com/Krounosity
* Learn more: https://en.wikipedia.org/wiki/Atbash
*/
public class AtbashCipher {
private String toConvert;
// Default constructor.
AtbashCipher() {
}
// String setting constructor.
AtbashCipher(String str) {
toConvert = str;
}
// String getter method.
public String getString() {
return toConvert;
}
// String setter method.
public void setString(String str) {
toConvert = str;
}
// Checking whether the current character is capital.
private boolean isCapital(char ch) {
return ch >= 'A' && ch <= 'Z';
}
// Checking whether the current character is smallcased.
private boolean isSmall(char ch) {
return ch >= 'a' && ch <= 'z';
}
// Converting text to atbash cipher code or vice versa.
public String convert() {
// Using StringBuilder to store new string.
StringBuilder convertedString = new StringBuilder();
// Iterating for each character.
for (char ch : toConvert.toCharArray()) {
// If the character is smallcased.
if (isSmall(ch)) {
convertedString.append((char) ('z' - (ch - 'a')));
}
// If the character is capital cased.
else if (isCapital(ch)) {
convertedString.append((char) ('Z' - (ch - 'A')));
}
// Non-alphabetical character.
else {
convertedString.append(ch);
}
}
return convertedString.toString();
}
}

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package com.thealgorithms.ciphers;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
public class AtbashTest {
@Test
public void atbashEncrypt() {
AtbashCipher normalToEncrypt = new AtbashCipher("Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!");
String expectedText = "Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!";
normalToEncrypt.setString(normalToEncrypt.convert());
assertEquals(expectedText, normalToEncrypt.getString());
}
@Test
public void atbashDecrypt() {
AtbashCipher encryptToNormal = new AtbashCipher("Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!");
String expectedText = "Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!";
encryptToNormal.setString(encryptToNormal.convert());
assertEquals(expectedText, encryptToNormal.getString());
}
}