diff --git a/Ciphers/KeyFinder.js b/Ciphers/KeyFinder.js
index b9121e1d91..64a3d1c9d4 100644
--- a/Ciphers/KeyFinder.js
+++ b/Ciphers/KeyFinder.js
@@ -1,7 +1,8 @@
-/******************************************************
- Find and retrieve the encryption key automatically
- Note: This is a draft version, please help to modify, Thanks!
- ******************************************************/
+/**
+ * Find and retrieve the encryption key automatically.
+ * @param {string} str - The input encrypted string.
+ * @returns {number} - The encryption key found, or 0 if not found.
+ */
 function keyFinder(str) {
   // str is used to get the input of encrypted string
   const wordBank = [
@@ -30,8 +31,6 @@ function keyFinder(str) {
     ' be ',
     'Be '
   ]
-  // let wordbankelementCounter = 0;
-  // let key = 0; // return zero means the key can not be found
   const inStr = str.toString() // convert the input to String
   let outStr = '' // store the output value
   let outStrElement = '' // temporary store the word inside the outStr, it is used for comparison
@@ -59,89 +58,95 @@ function keyFinder(str) {
   return 0 // return 0 if found nothing
 }
 
-/* this sub-function is used to assist the keyFinder to find the key */
+/**
+ * This sub-function is used to assist the keyFinder in finding the key.
+ * @param {string} inStr - The input string.
+ * @param {number} numShifted - The number of characters to shift in the Caesar cipher.
+ * @returns {string} - The decrypted string.
+ */
 function caesarCipherEncodeAndDecodeEngine(inStr, numShifted) {
   const shiftNum = numShifted
   let charCode = 0
-  let outStr = ''
   let shiftedCharCode = 0
   let result = 0
 
-  for (let i = 0; i < inStr.length; i++) {
-    charCode = inStr[i].charCodeAt()
-    shiftedCharCode = charCode + shiftNum
-    result = charCode
+  return inStr
+    .split('')
+    .map((char) => {
+      charCode = char.charCodeAt()
+      shiftedCharCode = charCode + shiftNum
+      result = charCode
 
-    if (charCode >= 48 && charCode <= 57) {
-      if (shiftedCharCode < 48) {
-        let diff = Math.abs(48 - 1 - shiftedCharCode) % 10
+      if (charCode >= 48 && charCode <= 57) {
+        if (shiftedCharCode < 48) {
+          let diff = Math.abs(48 - 1 - shiftedCharCode) % 10
 
-        while (diff >= 10) {
-          diff = diff % 10
-        }
-        document.getElementById('diffID').innerHTML = diff
+          while (diff >= 10) {
+            diff = diff % 10
+          }
+          document.getElementById('diffID').innerHTML = diff
 
-        shiftedCharCode = 57 - diff
+          shiftedCharCode = 57 - diff
 
-        result = shiftedCharCode
-      } else if (shiftedCharCode >= 48 && shiftedCharCode <= 57) {
-        result = shiftedCharCode
-      } else if (shiftedCharCode > 57) {
-        let diff = Math.abs(57 + 1 - shiftedCharCode) % 10
+          result = shiftedCharCode
+        } else if (shiftedCharCode >= 48 && shiftedCharCode <= 57) {
+          result = shiftedCharCode
+        } else if (shiftedCharCode > 57) {
+          let diff = Math.abs(57 + 1 - shiftedCharCode) % 10
 
-        while (diff >= 10) {
-          diff = diff % 10
-        }
-        document.getElementById('diffID').innerHTML = diff
+          while (diff >= 10) {
+            diff = diff % 10
+          }
+          document.getElementById('diffID').innerHTML = diff
 
-        shiftedCharCode = 48 + diff
+          shiftedCharCode = 48 + diff
 
-        result = shiftedCharCode
-      }
-    } else if (charCode >= 65 && charCode <= 90) {
-      if (shiftedCharCode <= 64) {
-        let diff = Math.abs(65 - 1 - shiftedCharCode) % 26
-
-        while (diff % 26 >= 26) {
-          diff = diff % 26
+          result = shiftedCharCode
         }
-        shiftedCharCode = 90 - diff
-        result = shiftedCharCode
-      } else if (shiftedCharCode >= 65 && shiftedCharCode <= 90) {
-        result = shiftedCharCode
-      } else if (shiftedCharCode > 90) {
-        let diff = Math.abs(shiftedCharCode - 1 - 90) % 26
-
-        while (diff % 26 >= 26) {
-          diff = diff % 26
+      } else if (charCode >= 65 && charCode <= 90) {
+        if (shiftedCharCode <= 64) {
+          let diff = Math.abs(65 - 1 - shiftedCharCode) % 26
+
+          while (diff % 26 >= 26) {
+            diff = diff % 26
+          }
+          shiftedCharCode = 90 - diff
+          result = shiftedCharCode
+        } else if (shiftedCharCode >= 65 && shiftedCharCode <= 90) {
+          result = shiftedCharCode
+        } else if (shiftedCharCode > 90) {
+          let diff = Math.abs(shiftedCharCode - 1 - 90) % 26
+
+          while (diff % 26 >= 26) {
+            diff = diff % 26
+          }
+          shiftedCharCode = 65 + diff
+          result = shiftedCharCode
         }
-        shiftedCharCode = 65 + diff
-        result = shiftedCharCode
-      }
-    } else if (charCode >= 97 && charCode <= 122) {
-      if (shiftedCharCode <= 96) {
-        let diff = Math.abs(97 - 1 - shiftedCharCode) % 26
-
-        while (diff % 26 >= 26) {
-          diff = diff % 26
-        }
-        shiftedCharCode = 122 - diff
-        result = shiftedCharCode
-      } else if (shiftedCharCode >= 97 && shiftedCharCode <= 122) {
-        result = shiftedCharCode
-      } else if (shiftedCharCode > 122) {
-        let diff = Math.abs(shiftedCharCode - 1 - 122) % 26
-
-        while (diff % 26 >= 26) {
-          diff = diff % 26
+      } else if (charCode >= 97 && charCode <= 122) {
+        if (shiftedCharCode <= 96) {
+          let diff = Math.abs(97 - 1 - shiftedCharCode) % 26
+
+          while (diff % 26 >= 26) {
+            diff = diff % 26
+          }
+          shiftedCharCode = 122 - diff
+          result = shiftedCharCode
+        } else if (shiftedCharCode >= 97 && shiftedCharCode <= 122) {
+          result = shiftedCharCode
+        } else if (shiftedCharCode > 122) {
+          let diff = Math.abs(shiftedCharCode - 1 - 122) % 26
+
+          while (diff % 26 >= 26) {
+            diff = diff % 26
+          }
+          shiftedCharCode = 97 + diff
+          result = shiftedCharCode
         }
-        shiftedCharCode = 97 + diff
-        result = shiftedCharCode
       }
-    }
-    outStr = outStr + String.fromCharCode(parseInt(result))
-  }
-  return outStr
+      return String.fromCharCode(parseInt(result))
+    })
+    .join('')
 }
 
 export { keyFinder }
diff --git a/DIRECTORY.md b/DIRECTORY.md
index 31969e4cd1..a7e5fe2c6c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -179,6 +179,7 @@
   * [DecimalExpansion](Maths/DecimalExpansion.js)
   * [DecimalIsolate](Maths/DecimalIsolate.js)
   * [DegreeToRadian](Maths/DegreeToRadian.js)
+  * [EuclideanDistance](Maths/EuclideanDistance.js)
   * [EulerMethod](Maths/EulerMethod.js)
   * [EulersTotient](Maths/EulersTotient.js)
   * [EulersTotientFunction](Maths/EulersTotientFunction.js)
@@ -249,6 +250,7 @@
   * [SumOfDigits](Maths/SumOfDigits.js)
   * [SumOfGeometricProgression](Maths/SumOfGeometricProgression.js)
   * [TwinPrime](Maths/TwinPrime.js)
+  * [TwoSum](Maths/TwoSum.js)
   * [Volume](Maths/Volume.js)
   * [WhileLoopFactorial](Maths/WhileLoopFactorial.js)
   * [ZellersCongruenceAlgorithm](Maths/ZellersCongruenceAlgorithm.js)