Sembra esserci alcuni dibattito sulla capacità o meno della scheda SD essere crittografato; Android non supportava la crittografia dei supporti esterni quando è stata introdotta e lo stato corrente di tale funzione sembra variare in modo significativo tra le varie versioni di Android.
La fonte più autorevole che riesco a trovare proviene da un post sul forum (l' autore potrebbe essere un tecnico del software Google:
2012/1/10 Marc Blank : The answer here is somewhat
nuanced. ActiveSync can require that the device and/or sd card be
encrypted, and we enforce those policies in ICS; however, ICS does not
have the ability to encrypt removable storage (i.e. SD cards). So
here's what happens:
1) In all current versions of ICS (up to 4.0.3), we accept the
"encrypt device" requirement and reject the "encrypt sd card" in all
cases (reject = we don't allow the account to be created/synced on
device) 2) In the next update to ICS, we will also accept "encrypt sd
card" if and only if the device is encrypted and it has no removable
volumes (this is true of the Nexus S and Galaxy Nexus); on these
devices, all internal storage is encrypted when device encryption is
enabled.
Having said that, the Email/Exchange application never stores emails
other than in internal storage; however, user can still choose to save
attachment files to "sd card" (which may or may not be external)
unless, of course, the ActiveSync policies are set up to disallow
loading of attachments.
Does this make sense? Sorry if it's complicated, but ... that's how
it is!
Marc
Detto questo, in generale sono d'accordo con il commento di Polynomial - sarà probabilmente impossibile recuperare il contenuto della scheda SD.