Add ROT13 cipher (TheAlgorithms#463)

iakgoog · Sutthinart Khunvadhana · itsvinayak · web-flow · commit 0ca9c8972736 · 2020-10-12T13:05:09.000+05:30
* Add ROT13 cipher

* Update ROT13.js

Co-authored-by: Sutthinart Khunvadhana &lt;sutthinart.khunvadhana@refinitiv.com&gt;
Co-authored-by: vinayak &lt;itssvinayak@gmail.com&gt;
diff --git a/Ciphers/ROT13.js b/Ciphers/ROT13.js
@@ -0,0 +1,21 @@
+/**
+ * Transcipher a ROT13 cipher
+ * @param  {String} text - string to be encrypted
+ * @return {String} - decrypted string
+ */
+const transcipher = (text) => {
+  const originalCharacterList = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
+  const toBeMappedCharaterList = 'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm'
+  const index = x => originalCharacterList.indexOf(x)
+  const replace = x => index(x) > -1 ? toBeMappedCharaterList[index(x)] : x
+  return text.split('').map(replace).join('')
+}
+
+(() => {
+  const messageToBeEncrypted = 'The quick brown fox jumps over the lazy dog'
+  console.log(`Original Text = "${messageToBeEncrypted}"`)
+  const rot13CipheredText = transcipher(messageToBeEncrypted)
+  console.log(`Ciphered Text = "${rot13CipheredText}"`)
+  const rot13DecipheredText = transcipher(rot13CipheredText)
+  console.log(`Deciphered Text = "${rot13DecipheredText}"`)
+})()
