In light of current events (Zoom getting strong headwinds for using AES-128 in ECB mode), I was wondering what the general approach is to packetized data encryption, where the packet length (UDP for video over internet: > 1200 B payload)
- Is it really just a block cipher in ECB mode, so that each packet can be decoded without any prior packet⁰?
- Is it a block cipher in some non-ECB mode, but it gets reset at the start of a packet?
- Is it a block cipher in some non-ECB mode, but we're just using a sufficiently large number of say $N$ different keys, de- and encoder, which we use in interleaved / sequential fashion, so that any erasure of less than $N$ successive packets gives us enough time to let the transmitter know we need to re-initialize the receiver?¹
- Would you go the WiFi/WPA route of deriving a key for each packet, leading to the couple of attacks we know against that TKIP/KDF method?
- Am I totally missing everything?
I've tried to look into how KASUMI (3G crypto standard) does this, but I haven't been able to track down the relevant standards document.
⁰ ... and everyone is bashing Zoom for adhering to industry best practice?
¹ wouldn't that lead to feasibility of forcing the encoder to a known state by an attacker with control over which packets get lost?