How do police access encrypted Android devices?

In the UK the police routinely seize all electronic devices when arresting someone, at least if there's any suggestion of Internet usage in the alleged crime, such as posting 'offensive' words on Twitter, emailing someone else about the crime.

They ask you to give them all your passwords to unlock the devices but if you refuse I don't think it matters, it just takes them more time to access them.

All Android devices are encrypted by default now, so how …

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