diff --git a/index.html b/index.html
index 4886495..e6024f8 100644
--- a/index.html
+++ b/index.html
@@ -16,8 +16,8 @@
       <div class="keycard-ident__form-container" id="ident-form">
         <div class="keycard-ident__form">
           <div class="keycard-ident__form-field-container group">
-            <label for="lot-number" class="keycard-ident__form-field-label">Lot number</label>
-            <input type="text" class="keycard-ident__form-field-input-text keycard__inp-right" id="lot-number" name="lot-number" placeholder="Lot number" required>
+            <label for="lot-number" class="keycard-ident__form-field-label">Version &amp; lot identifier</label>
+            <input type="text" class="keycard-ident__form-field-input-text keycard__inp-right" id="lot-number" name="lot-number" placeholder="V2XX" required>
           </div>
           <div class="keycard-ident__form-field-container group">
             <label for="card-quantity" class="keycard-ident__form-field-label">Number of cards</label>
diff --git a/src/card.ts b/src/card.ts
index cbe5e57..84480ab 100644
--- a/src/card.ts
+++ b/src/card.ts
@@ -1,6 +1,6 @@
 import Keycard from "keycard-sdk"
 import { WebContents } from "electron";
-import { ipcMain, dialog } from "electron"
+import { ipcMain, dialog } from "electron";
 import { SessionInfo } from "./session-info";
 import { Utils } from "./utils";
 import { Pairing } from "keycard-sdk/dist/pairing";
@@ -193,8 +193,7 @@ export class Card {
     for (let i = 0; i < cards; i++) {
       let certificate = Certificate.generateNewCertificate(caKey);
       let certData = certificate.toStoreData();
-      let num = Utils.formatNumtoString(i);
-      let cardID = lot + num;
+      let cardID = lot + '-' + Utils.uint20ToBase32(i);
       let certDataString = dataHeader + Buffer.from(certData).toString('hex');
       let line = cardID + "," + certDataString + "\n";
       encData += line;
@@ -210,11 +209,12 @@ export class Card {
     this.window.send("certificate-creation-success");
   }
 
-  openDestinationDialog(): void {
+  openDestinationDialog(lot: string): void {
+    let fileName = lot ? lot + '.csv.asc' : 'certificates.csv.asc';
     let options = {
       title: 'Select the destination path to save the processed file',
       buttonLabel: "Choose",
-      defaultPath: path.join(__dirname, 'certificates.csv.asc'),
+      defaultPath: path.join(__dirname, fileName),
       filters: [
         {
           name: 'ASC Files',
@@ -296,6 +296,6 @@ export class Card {
     ipcMain.on("verify-pin", this.withErrorHandler(this.verifyPIN));
     ipcMain.on("verify-puk", this.withErrorHandler(this.verifyPUK));
     ipcMain.on("start-ident", this.withErrorHandler(this.identCert));
-    ipcMain.on("open-destination-folder-dialog", (_) => this.openDestinationDialog());
+    ipcMain.on("open-destination-folder-dialog", (_, lot) => this.openDestinationDialog(lot));
   }
 }
\ No newline at end of file
diff --git a/src/ident.ts b/src/ident.ts
index b6bc53e..cd99e3a 100644
--- a/src/ident.ts
+++ b/src/ident.ts
@@ -31,7 +31,7 @@ export namespace Ident {
     });
 
     destinationPathBtn.addEventListener("click", (e) => {
-      ipcRenderer.send("open-destination-folder-dialog");
+      ipcRenderer.send("open-destination-folder-dialog", lot.value);
     });
 
     ipcRenderer.on("verification-success", (_) => {
diff --git a/src/utils.ts b/src/utils.ts
index 981656f..749a67a 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,5 +1,6 @@
 export namespace Utils {
   const numStrLength = 6;
+  const RFC4648 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
 
   export function hx(arr: Uint8Array): string {
     return Buffer.from(arr).toString('hex');
@@ -23,4 +24,10 @@ export namespace Utils {
 
     return res;
   }
+
+
+
+  export function uint20ToBase32(num: number): string {
+    return RFC4648.charAt((num >> 15) & 0x1F) + RFC4648.charAt((num >> 10) & 0x1F) + RFC4648.charAt((num >> 5) & 0x1F) + RFC4648.charAt(num & 0x1F)
+  }
 }
\ No newline at end of file