diff --git a/src/core/operations/AffineCipherDecode.mjs b/src/core/operations/AffineCipherDecode.mjs
index 78666d10..45316f9a 100644
--- a/src/core/operations/AffineCipherDecode.mjs
+++ b/src/core/operations/AffineCipherDecode.mjs
@@ -5,8 +5,7 @@
  */
 
 import Operation from "../Operation.mjs";
-import Utils from "../Utils.mjs";
-import OperationError from "../errors/OperationError.mjs";
+import { affineDecrypt, affineDecryptInverse, AFFINE_ALPHABETS } from "../lib/Ciphers.mjs";
 
 /**
  * Affine Cipher Decode operation
@@ -36,6 +35,11 @@ class AffineCipherDecode extends Operation {
                 "type": "number",
                 "value": 0
             },
+            {
+                "name": "Alphabet",
+                "type": "editableOption",
+                "value": AFFINE_ALPHABETS
+            },
             {
                 "name": "Use modular inverse values",
                 "type": "boolean",
@@ -52,43 +56,9 @@ class AffineCipherDecode extends Operation {
      * @throws {OperationError} if a or b values are invalid
      */
     run(input, args) {
-        const alphabet = "abcdefghijklmnopqrstuvwxyz",
-            [a, b, useInv] = args,
-            aModInv = Utils.modInv(a, 26); // Calculates modular inverse of a
-        let output = "";
-
-        if (!/^\+?(0|[1-9]\d*)$/.test(a) || !/^\+?(0|[1-9]\d*)$/.test(b)) {
-            throw new OperationError("The values of a and b can only be integers.");
-        }
-
-        if (Utils.gcd(a, 26) !== 1) {
-            throw new OperationError("The value of `a` must be coprime to 26.");
-        }
-
-        for (let i = 0; i < input.length; i++) {
-            if (alphabet.indexOf(input[i]) >= 0) {
-                if (useInv) {
-                    // Uses the affine decode function (y+b)*a % m, where m is the length
-                    // of the alphabet and a,b are modular inverses of the original a,b
-                    output += alphabet[Utils.mod((alphabet.indexOf(input[i]) + b) * a, 26)];
-                } else {
-                    // Uses the affine decode function (y-b * A') % m = x (where m is length of the alphabet and A' is modular inverse)
-                    output += alphabet[Utils.mod((alphabet.indexOf(input[i]) - b) * aModInv, 26)];
-                }
-            } else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
-                if (useInv) {
-                    // Same as above, accounting for uppercase
-                    output += alphabet[Utils.mod((alphabet.indexOf(input[i].toLowerCase()) + b) * a, 26)].toUpperCase();
-                } else {
-                    // Same as above, accounting for uppercase
-                    output += alphabet[Utils.mod((alphabet.indexOf(input[i].toLowerCase()) - b) * aModInv, 26)].toUpperCase();
-                }
-            } else {
-                // Non-alphabetic characters
-                output += input[i];
-            }
-        }
-        return output;
+        const a = args[0], b = args[1], alphabet = args[2], useInverse = args[3];
+        if (useInverse) return affineDecryptInverse(input, a, b, alphabet);
+        else return affineDecrypt(input, a, b, alphabet);
     }
 
     /**