Which gives better deterministic encryption SIV or Plain ECB mode? Lets say , if we encrypt a plain text message $msg$ with key $key$ in below two ways. Which is the below would give better deterministic encryption and why ?


AES-ECB($key$ , $msg$)
SIV($key$, NIL , $msg$) where associated data is NIL.


I could not make out much from Rogaway and Shrimpton's paper on "Deterministic Authenticated Encryption" which introduces Synthentic IV (SIV) mode.

Edit: Here $msg$ is same as single block .
Both:


Secure deterministic encryption for one-block messages.


ECB:


No expansion for block-sized messages.
Faster.


SIV:


Authentication.
Works for messages of any size.