  Sensitive digital data, such as health information or governmental archives,
are often stored for decades or centuries. The processing of such data calls
for long-term security. Secure channels on the Internet require robust key
establishment methods. Currently used key distribution protocols are either
vulnerable to future attacks based on Shor's algorithm, or vulnerable in
principle due to their reliance on computational problems. Quantum-based key
distribution protocols are information-theoretically secure and offer long-term
security. However, significant obstacles to their real-world use remain. This
paper, which results from a multidisciplinary project involving computer
scientists and physicists, systematizes knowledge about obstacles to and
strategies for the realization of long-term secure Internet communication from
quantum-based key distribution. We discuss performance and security
particulars, consider the specific challenges arising from multi-user network
settings, and identify key challenges for actual deployment.
