GCHQ keeps the content of messages for three working days, and the simple "metadata" – which includes details of who sent and received them – for up to 30 days.
It is unclear what sort of legal process the government serves on a company to compel communications content and metadata access under Prism or through upstream collection.
It's to make the case that this metadata paints a very revealing portrait of oneself".
But the prominence of Rachel in the graph is, for me, a reminder that one of the reasons we might be concerned about metadata is that it shows strong relationships, whether those relationships are widely known or are secret".
"After May 22, 2015, the National Security Agency will need to begin taking steps to wind down the bulk telephone metadata program in anticipation of a possible sunset in order to ensure that it does not engage in any unauthorized collection or use of the metadata," states the memo, circulated on Capitol Hill and first reported by National Journal.
Passage on a bipartisan basis is expected for the USA Freedom Act on Wednesday, a bill that seeks to stop the NSA from collecting the metadata of all US phone calls.
Rajesh De, the NSA general counsel, said all communications content and associated metadata harvested by the NSA under a 2008 surveillance law occurred with the knowledge of the companies – both for the internet collection program known as Prism and for the so-called "upstream" collection of communications moving across the internet.
Access to metadata, live content, or the stored content of personal communications must only take place without consent where there is reasonable suspicion of criminal activity or to prevent threats to life".
Illegal interception of the metadata of a message breaks your anonymity.
We already know how detailed an account of an individual's daily life can be constructed from metadata extracted from a mobile phone.
Entitled "Me and my metadata", it explains what happened when two of his students wrote a program to analyse his Gmail account and create from the metadata therein a visualisation of his social network (and of his private life), which he then publishes and discusses in detail.
