They (used to) use SILK as their audio compression/codec, created by Skype. https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the-co

They (used to) use SILK as their audio compression/codec, created by Skype. https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the-confidentiality-of-zoom-meetings/ https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto...