diff --git a/src/core/operations/ParseX509Certificate.mjs b/src/core/operations/ParseX509Certificate.mjs
index 8af7040..a57f661 100644
--- a/src/core/operations/ParseX509Certificate.mjs
+++ b/src/core/operations/ParseX509Certificate.mjs
@@ -181,8 +181,8 @@ class ParseX509Certificate extends Operation {
 Serial number:    ${new r.BigInteger(sn, 16).toString()} (0x${sn})
 Algorithm ID:     ${cert.getSignatureAlgorithmField()}
 Validity
-  Not Before:     ${nbDate} (dd-mm-yy hh:mm:ss) (${cert.getNotBefore()})
-  Not After:      ${naDate} (dd-mm-yy hh:mm:ss) (${cert.getNotAfter()})
+  Not Before:     ${nbDate} (dd-mm-yyyy hh:mm:ss) (${cert.getNotBefore()})
+  Not After:      ${naDate} (dd-mm-yyyy hh:mm:ss) (${cert.getNotAfter()})
 Issuer
 ${issuerStr}
 Subject
@@ -206,12 +206,15 @@ ${extensions}`;
  * @returns {string}
  */
 function formatDate (dateStr) {
-    return dateStr[4] + dateStr[5] + "/" +
-        dateStr[2] + dateStr[3] + "/" +
-        dateStr[0] + dateStr[1] + " " +
-        dateStr[6] + dateStr[7] + ":" +
+    if (dateStr.length === 13) { // UTC Time
+        dateStr = (dateStr[0] < "5" ? "20" : "19") + dateStr;
+    }
+    return dateStr[6] + dateStr[7] + "/" +
+        dateStr[4] + dateStr[5] + "/" +
+        dateStr[0] + dateStr[1] + dateStr[2] + dateStr[3] + " " +
         dateStr[8] + dateStr[9] + ":" +
-        dateStr[10] + dateStr[11];
+        dateStr[10] + dateStr[11] + ":" +
+        dateStr[12] + dateStr[13];
 }
 
 export default ParseX509Certificate;