Echo crypto suite tag of the offer SDP in the answer SDP - #17
Merged
Conversation
Currently, when Livekit generates an answer SDP, the crypto suite will have a tag value of whatever index was assigned to it by ``DefaultProfiles()``. This is a problem in case the offerer strictly validates that the tag in the answer is equal to the one in the offer. RFC 4568 section 5.1.3: ``` When the offerer receives the answer, the offerer MUST verify that one of the initially offered crypto suites and its accompanying tag were accepted and echoed in the answer ``` This patch should solve the last of the SDES-related compatibility issues with rtpengine that I encountered. Note that this does not address the fact that Livekit ignores the crypto suite tag when processing an answer SDP.
dennwc
approved these changes
Aug 27, 2025
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Currently, when Livekit generates an answer SDP, the crypto suite will have a tag value of whatever index was assigned to it by
DefaultProfiles(). This is a problem in case the offerer strictly validates that the tag in the answer is equal to the one in the offer.RFC 4568 section 5.1.3:
This patch should solve the last of the SDES-related compatibility issues with rtpengine that I encountered.
Note that this does not address the fact that Livekit ignores the crypto suite tag when processing an answer SDP.