A decent example being Article 8 of the European Convention on Human Rights:

>1. Everyone has the right to respect for his private and family life, his home and his correspondence.

>2. There shall be no interference by a public authority with the exercise of this right except such as is in accordance with the law and is necessary in a democratic society in the interests of national security, public safety or the economic well-being of the country, for the prevention of disorder or crime, for the protection of health or morals, or for the protection of the rights and freedoms of others.

Specifically:

>A 2014 report to the UN General Assembly by the United Nations' top official for counter-terrorism and human rights condemned mass electronic surveillance as a clear violation of core privacy rights guaranteed by multiple treaties and conventions and makes a distinction between "targeted surveillance" – which "depend[s] upon the existence of prior suspicion of the targeted individual or organization" – and "mass surveillance", by which "states with high levels of Internet penetration can [] gain access to the telephone and e-mail content of an effectively unlimited number of users and maintain an overview of Internet activity associated with particular websites". Only targeted interception of traffic and location data in order to combat serious crime, including terrorism, is justified, according to a decision by the European Court of Justice.[23]

https://en.wikipedia.org/wiki/Article_8_of_the_European_Conv...