For 128 bit SRTP encryption, total size (182) ->12 bytes header -> the payload of size 160 bytes is displayed in wireshark as "SRTP Encrypted payload" -> 10 bytes of SRTP auth Tag is displayed. User Datagram Protocol, Src Port: 10000, Dst Port: 4014 Source Port: 10000 Destination Port: 4014 Length: 190 Checksum: 0x17fa [unverified] [Checksum Status: Unverified] [Stream index: 1379] [Timestamps] UDP payload (182 bytes) Real-Time Transport Protocol [Stream setup by SDP (frame 28688)] 10.. .... = Version: RFC 1889 Version (2) ..0. .... = Padding: False ...0 .... = Extension: False .... 0000 = Contributing source identifiers count: 0 0... .... = Marker: False Payload type: ITU-T G.711 PCMU (0) Sequence number: 0 [Extended sequence number: 65536] Timestamp: 434670322 Synchronization Source identifier: 0x0af5d54b (183883083) SRTP Encrypted Payload: 2d64b7464dd84f523edff434efade54a96446c118b2cc8ffc107a21efcd889bebc6d5fa9… SRTP Auth Tag: ca9be8fde9ec0a192491
In 256 bit encryption, only SRTP Encrypted payload is displayed in wireshark. SRTP auth Tag is not shown. Total of 170 bytes(160 bytes payload + 10 bytes auth tag) is displayed as SRTP encrypted payload.
Internet Protocol Version 4, Src: 10.90.1.59, Dst: 10.90.1.60 User Datagram Protocol, Src Port: 10000, Dst Port: 4012 Source Port: 10000 Destination Port: 4012 Length: 190 Checksum: 0x17fa [unverified] [Checksum Status: Unverified] [Stream index: 295] [Timestamps] UDP payload (182 bytes) Real-Time Transport Protocol [Stream setup by SDP (frame 7603)] [Setup frame: 7603] [Setup Method: SDP] [Generated Call-ID: [email protected]] 10.. .... = Version: RFC 1889 Version (2) ..0. .... = Padding: False ...0 .... = Extension: False .... 0000 = Contributing source identifiers count: 0 0... .... = Marker: False Payload type: ITU-T G.711 PCMU (0) Sequence number: 86 [Extended sequence number: 65622] Timestamp: 434225132 Synchronization Source identifier: 0x682785f4 (1747420660) SRTP Encrypted Payload: 6fe717d486ce42a571a0d27e1a692ab36101773ba9c6f35dd30c6794cf6612eb3608770d…
