  The problem of adopting quantum-resistant cryptographic network protocols or
post-quantum cryptography (PQC) is critically important to democratizing
quantum computing. The problem is urgent because practical quantum computers
will break classical encryption in the next few decades. Past encrypted data
has already been collected and can be decrypted in the near future. The main
challenges of adopting post-quantum cryptography lie in algorithmic complexity
and hardware/software/network implementation. The grand question of how
existing cyberinfrastructure will support post-quantum cryptography remains
unanswered.
  This paper describes: i) the design of a novel Post-Quantum Cryptography
(PQC) network instrument placed at the National Center for Supercomputing
Applications (NCSA) at the University of Illinois at Urbana-Champaign and a
part of the FABRIC testbed; ii) the latest results on PQC adoption rate across
a wide spectrum of network protocols (Secure Shell -- SSH, Transport Layer
Security -- TLS, etc.); iii) the current state of PQC implementation in key
scientific applications (e.g., OpenSSH or SciTokens); iv) the challenges of
being quantum-resistant; and v) discussion of potential novel attacks.
  This is the first large-scale measurement of PQC adoption at national-scale
supercomputing centers and FABRIC testbeds. Our results show that only OpenSSH
and Google Chrome have successfully implemented PQC and achieved an initial
adoption rate of 0.029% (6,044 out of 20,556,816) for OpenSSH connections at
NCSA coming from major Internet Service Providers or Autonomous Systems (ASes)
such as OARNET, GTT, Google Fiber Webpass (U.S.) and Uppsala Lans Landsting
(Sweden), with an overall increasing adoption rate year-over-year for
2023-2024. Our analyses identify pathways to migrate current applications to be
quantum-resistant.
