It is true that Cellebrite blog post looks like an amateur work. However, an important context is missing from signal' blog post:
Cellebrite specializes in breaking and extracting data from encrypted partitions, and (this is the important part) extracting keys from the secure keystore (Qualcomm/exynos).
From Cellebrite point of view, the data and keystore are already "given", all the remains is "breaking" the app encryption scheme, which in signal's case is trivial.
Cellebrite specializes in breaking and extracting data from encrypted partitions, and (this is the important part) extracting keys from the secure keystore (Qualcomm/exynos).
From Cellebrite point of view, the data and keystore are already "given", all the remains is "breaking" the app encryption scheme, which in signal's case is trivial.