Cisco names AES-CM-128-HMAC-SHA1 as the cipher typically used to encrypt media to Webex services from endpoints using SRTP with SIP signalling and describes it as a mature cipher with proven interoperability between vendors, and the Webex Calling security requirements article gives AES_CM_128_HMAC_SHA1_80 as the only SRTP key supported for secure media.

Checked 2026-09-16

Vendor
Cisco
Product
Webex
Subsystem
media
Deployment
not restricted
Region
not restricted
Release range
not restricted
Checked
2026-09-16

Sources

Cite this note

APA

WarmTransfer. (2026, September 16). Firewall ports and IP ranges for cloud calling: source note fwports-srtp-cipher-is-a-single-suite. WarmTransfer. https://warmtransfer.net/knowledge/claims/fwports-srtp-cipher-is-a-single-suite

BibTeX

@misc{warmtransfer-claim-fwports-srtp-cipher-is-a-single-suite,
  title  = {Firewall ports and IP ranges for cloud calling: source note fwports-srtp-cipher-is-a-single-suite},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/fwports-srtp-cipher-is-a-single-suite},
  note   = {Source note fwports-srtp-cipher-is-a-single-suite, checked 2026-09-16}
}

Read in context