diff --git a/index.js b/index.js
index eb94b4b..461abb2 100644
--- a/index.js
+++ b/index.js
@@ -114,7 +114,7 @@ function sign_object (obj, key, key_info = null) {
  *
  * @param {string} str string to verify
  * @param {string|(Object)=>string} key used key
- * @param {number} timeout timeout (optional)
+ * @param {number|(Object)=>number} timeout timeout (optional)
  * @returns {any} returns object if successful, else null
  */
 function verify_signature_get_info (str, key, timeout = 0) {
@@ -129,9 +129,10 @@ function verify_signature_get_info (str, key, timeout = 0) {
   if (token !== verify_token)
     return null;
   const time = Date.now () - json.iat;
-  if (timeout !== 0 && time > timeout)
-    return null;
-  return json;
+  const num_timeout = typeof timeout === 'number' ? timeout : timeout (json);
+  if (num_timeout === 0 || time <= num_timeout)
+    return json;
+  return null;
 }
 
 /**
@@ -139,7 +140,7 @@ function verify_signature_get_info (str, key, timeout = 0) {
  *
  * @param {string} str string to verify
  * @param {string|(Object)=>string} key used key
- * @param {number} timeout timeout (optional)
+ * @param {number|(Object)=>number} timeout timeout (optional)
  * @returns {any} returns object if successful, else null
  */
 function verify_signature (str, key, timeout = 0) {
diff --git a/package.json b/package.json
index 864d38c..6f01913 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@sapphirecode/crypto-helper",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "main": "index.js",
   "author": {
     "name": "Timo Hocker",
diff --git a/test/spec/index.js b/test/spec/index.js
index f216f50..100fbc2 100644
--- a/test/spec/index.js
+++ b/test/spec/index.js
@@ -174,6 +174,14 @@ describe ('crypto helper', () => {
       .toEqual (dec);
   });
 
+  it ('should verify signature using function retrieved timeout 0', () => {
+    const obj = { foo: 'bar' };
+    const str = crypto.sign_object (obj, 'baz');
+    const dec = crypto.verify_signature (str, 'baz', () => 0);
+    expect (obj)
+      .toEqual (dec);
+  });
+
   it ('should reject tampered signatures', () => {
     const obj = { foo: 'bar' };
     const str = crypto.sign_object (obj, 'baz');
@@ -254,6 +262,27 @@ describe ('crypto helper', () => {
       .uninstall ();
   });
 
+  it ('should verify signature using function retrieved timeout', () => {
+    jasmine.clock ()
+      .install ();
+    const base_time = (new Date);
+    jasmine.clock ()
+      .mockDate (base_time);
+
+    const obj = { foo: 'bar' };
+    const str = crypto.sign_object (obj, 'baz', { to: 100 });
+
+    jasmine.clock ()
+      .tick (50);
+
+    const dec = crypto.verify_signature (str, 'baz', (info) => info.to);
+    expect (obj)
+      .toEqual (dec);
+
+    jasmine.clock ()
+      .uninstall ();
+  });
+
   it ('verify_signature on almost timed out packet', () => {
     jasmine.clock ()
       .install ();