2000s
As evidenced by the Hainan Island incident, even while China and the US may cooperate on matters of mutual concern towards Russia, the Cold War has not completely disappeared.
There was more regional cooperation, often driven by concerns about transnational terrorism. European countries also are finding that by sharing the cost, they can acquire SIGINT, IMINT, and MASINT capabilities independent of the US.
In the US, both communications security and COMINT policies have been evolving, some with challenges. The adoption of a Belgian-developed encryption algorithm, approved in a public process, and accepted both for sensitive but unclassified traffic, as well as for classified information sent with NSA-generated and maintained keys, redraws the cryptologic environment as no longer NSA or not-NSA. Controversy continues on various types of COMINT justified as not requiring warrants, under the wartime authority of the President of the United States.
Technologically, there was much greater use of UAVs as SIGINT collection platforms.
Read more about this topic: Signals Intelligence In Modern History