Encryption for Zoom Phone

All SIP devices, desktops, and mobile clients supported by Zoom can make secure voice calls. During phone provisioning sessions and during SIP over TLS 1.2 calls, Zoom Phone supports standards-based encryption using AES 256-bit algorithms. In addition, Zoom desktop and mobile clients and devices use SRTP and AES-256 bit algorithms for call media transmission and security.


Devices by default are encrypted with AES-128 bits. The admin needs to upgrade devices to AES-256 bit encryption through the web portal in order to access the devices.

Zoom Phone desktop client and mobile app

It can communicate over SIP (SIP signaling) with the server over TLS1.2 with a level of encryption of AES-256, which is supported since Zoom Phone version 5.0.0 and higher. We use SRTP with 256-bit AES encryption to transport and protect media calls.

Zoom Phone devices

As part of its standard-based encryption process, Zoom Phone supports the AES 256-bit Advanced Encryption Standard (AES) standard that is supported by SIP over TLS 1.2 to protect calls. SRTP is additionally used for all devices to transport and protect call media. Supported devices can be encrypted with AES-256 bit by zoom Phone admins. Click here to learn more.

Upgrade to AES-256 bit encryption

AES-256 bit encryption can be upgraded in specific models on a site.

  1. Zoom’s web portal requires logging in.
  2. Then click on Phone System Management from the menu bar and then click on Company Information.
  3. If you have more than one site, then you can select the one you want to edit by clicking on its title.
  4. Click on the Settings tab.
  5. Select the Add button under the Security section.
  6. Specify a model and a brand, then click Save.
  7. Continue by repeating steps 5 and 6 until you have added all the devices.

Downgrading to AES-128 bit encryption

It is possible to downgrade to AES-128 bit encryption if you previously upgraded to AES-256 bit encryption.

  1. Join the Zoom web portal by logging in.
  2. Select Management of Phone Systems in the navigation menu, then select Details of a Company from the menu.
  3. Select the site you wish to edit from the list if you have more than one.
  4. Click on the Settings tab.
  5. To downgrade the security model to AES-128 bit encryption, click the icon in the Security section.