How is it any more possible to prove a chatlog wasn't forged, given that third-parties cannot verify these signatures (only Google can, if TFA is correct) and Google already keeps unlimited retention of their chat logs and thus could do the verification without any signature field? Plus, not all clients cause a signature to be inserted, so even the lack of a signature wouldn't imply forgery.
The article and/or its interpretation is wrong about that because the algo is unknown.
Even worse, human beings both currently and formerly employed by GOOG know the secret-ish algo, and those humans are not necessarily still employed there, nor are they incapable of communication. So its very unclear who knows how that algo works other than GOOG as an absolute minimum.
A correct statement would be, at the minimum at least GOOG knows how to make those hashes, and at this instant who knows how many other people or orgs who may or may not be in support or opposition to you.
