diff --git a/package.json b/package.json
index 628676e..f212613 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "d3-ots",
-  "version": "0.4.3",
+  "version": "0.4.4",
   "private": true,
   "scripts": {
     "serve": "vue-cli-service serve",
diff --git a/src/views/SignTX.vue b/src/views/SignTX.vue
index 983924a..bff1ae8 100644
--- a/src/views/SignTX.vue
+++ b/src/views/SignTX.vue
@@ -208,10 +208,19 @@ export default {
       this.isZipFile = false
     },
     onSignAndDownload () {
+      const _keyPattern = (value) => {
+        const pattern = /^[A-Fa-f0-9]{64}$/
+        if (!pattern.test(value)) return false
+        return true
+      }
       if (!this.sign.privateKey.length) {
         this.$message.error('Private key can\'t be empty!')
         return
       }
+      if (!_keyPattern(this.sign.privateKey)) {
+        this.$message.error('Invalid private key!')
+        return
+      }
       if (this.isZipFile) {
         this.onSignZip()
           .then(txs => this.onSaveTransactions(txs))