2. The IETF Will Work to Mitigate Pervasive Monitoring
2. The IETF Will Work to Mitigate Pervasive Monitoring
"Mitigation" is a technical term that does not imply an ability to completely prevent or thwart an attack. Protocols that mitigate PM will not prevent the attack but can significantly change the threat. (See the diagram on page 24 of RFC 4949 for how the terms "attack" and "threat" are related.) This can significantly increase the cost of attacking, force what was covert to be overt, or make the attack more likely to be detected, possibly later.
IETF standards already provide mechanisms to protect Internet communications and there are guidelines [RFC3552] for applying these in protocol design. But those standards generally do not address PM, the confidentiality of protocol metadata, countering traffic analysis, or data minimisation. In all cases, there will remain some privacy-relevant information that is inevitably disclosed by protocols. As technology advances, techniques that were once only available to extremely well-funded actors become more widely accessible. Mitigating PM is therefore a protection against a wide range of similar attacks.
It is therefore timely to revisit the security and privacy properties of our standards. The IETF will work to mitigate the technical aspects of PM, just as we do for protocol vulnerabilities in general. The ways in which IETF protocols mitigate PM will change over time as mitigation and attack techniques evolve and so are not described here.
Those developing IETF specifications need to be able to describe how they have considered PM, and, if the attack is relevant to the work to be published, be able to justify related design decisions. This does not mean a new "pervasive monitoring considerations" section is needed in IETF documentation. It means that, if asked, there needs to be a good answer to the question "Is pervasive monitoring relevant to this work and if so, how has it been considered?"
In particular, architectural decisions, including which existing technology is reused, may significantly impact the vulnerability of a protocol to PM. Those developing IETF specifications therefore need to consider mitigating PM when making architectural decisions. Getting adequate, early review of architectural decisions including whether appropriate mitigation of PM can be made is important. Revisiting these architectural decisions late in the process is very costly.
While PM is an attack, other forms of monitoring that might fit the definition of PM can be beneficial and not part of any attack, e.g., network management functions monitor packets or flows and anti-spam mechanisms need to see mail message content. Some monitoring can even be part of the mitigation for PM, for example, certificate transparency [RFC6962] involves monitoring Public Key Infrastructure in ways that could detect some PM attack techniques. However, there is clear potential for monitoring mechanisms to be abused for PM, so this tension needs careful consideration in protocol design. Making networks unmanageable to mitigate PM is not an acceptable outcome, but ignoring PM would go against the consensus documented here. An appropriate balance will emerge over time as real instances of this tension are considered.
Finally, the IETF, as a standards development organisation, does not control the implementation or deployment of our specifications (though IETF participants do develop many implementations), nor does the IETF standardise all layers of the protocol stack. Moreover, the non-technical (e.g., legal and political) aspects of mitigating pervasive monitoring are outside of the scope of the IETF. The broader Internet community will need to step forward to tackle PM, if it is to be fully addressed.
To summarise: current capabilities permit some actors to monitor content and metadata across the Internet at a scale never before seen. This pervasive monitoring is an attack on Internet privacy. The IETF will strive to produce specifications that mitigate pervasive monitoring attacks.