https://www.freehaven.net/anonbib/cache/raptor-sec2015.pdf "Among others, the NSA has a program called Marina which stores meta information about user communications for up to a year [15], while the GCHQ has a program called Tempora that stores meta-information for 30 days and buffers data for three days [36]. Also, and maybe more importantly, it has been shown that Tor was targeted by such adversaries in collusion with ASes [10, 12, 11]. In this paper, we present Raptor, a suite of novel traffic analysis attacks that deanonymize Tor users more effectively than previously thought possible. To do so, and unlike previous studies on AS-level adversaries [28, 26,40], Raptor leverages the dynamic aspects of the Internet routing protocol, i.e. the Border Gateway Protocol (BGP)."