diff --git a/src/core/operations/OTP.js b/src/core/operations/OTP.js
index ff67d1c8..20205053 100755
--- a/src/core/operations/OTP.js
+++ b/src/core/operations/OTP.js
@@ -1,5 +1,6 @@
 import otp from "otp";
 import Base64 from "./Base64.js";
+import Utils from "../Utils.js";
 
 /**
  * One-Time Password operations.
@@ -24,7 +25,7 @@ const OTP = {
             name: args[0],
             keySize: args[1],
             codeLength: args[2],
-            secret: Base64.runTo32(input, []),
+            secret: Base64.runTo32(Utils.strToByteArray(input), []),
             epoch: args[3],
             timeSlice: args[4]
         });
@@ -44,7 +45,7 @@ const OTP = {
             name: args[0],
             keySize: args[1],
             codeLength: args[2],
-            secret: Base64.runTo32(input, []),
+            secret: Base64.runTo32(Utils.strToByteArray(input), []),
         });
         const counter = args[3];
         return `URI: ${otpObj.hotpURL}\n\nPassword: ${otpObj.hotp(counter)}`;
diff --git a/test/index.js b/test/index.js
index 748e1103..7f029b8d 100644
--- a/test/index.js
+++ b/test/index.js
@@ -26,6 +26,7 @@ import "./tests/operations/Image.js";
 import "./tests/operations/MorseCode.js";
 import "./tests/operations/MS.js";
 import "./tests/operations/PHP.js";
+import "./tests/operations/OTP.js";
 import "./tests/operations/StrUtils.js";
 import "./tests/operations/SeqUtils.js";
 
diff --git a/test/tests/operations/OTP.js b/test/tests/operations/OTP.js
new file mode 100644
index 00000000..b321e7cf
--- /dev/null
+++ b/test/tests/operations/OTP.js
@@ -0,0 +1,23 @@
+/**
+ * OTP HOTP tests.
+ *
+ * @author bwhitn [brian.m.whitney@outlook.com]
+ *
+ * @copyright Crown Copyright 2017
+ * @license Apache-2.0
+ */
+import TestRegister from "../../TestRegister.js";
+
+TestRegister.addTests([
+    {
+        name: "Generate HOTP",
+        input: "12345678901234567890",
+        expectedOutput: "URI: otpauth://hotp/OTPAuthentication?secret=GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ\n\nPassword: 755224",
+        recipeConfig: [
+            {
+                op: "Generate HOTP",
+                args: ["", 32, 6, 0],
+            },
+        ],
+    },
+]);