The implications of sufficiently large quantum computers for widely used public-key cryptography is well-documented and increasingly discussed by the security community. An April 2016 report by the National Institute of Standards and Technology (NIST), notably, calls out the need for new standards to replace cryptosystems based on integer factorization and discrete logarithm problems, which have been shown to be vulnerable to Shor's quantum algorithm for prime factorization. Specifically, widely used RSA, ECDSA, ECDH, and DSA cryptosystems will need to be replaced by post-quantum cryptography (PQC) alternatives (also known as quantum-resistant or quantum-safe cryptography). Failure to transition before sufficiently powerful quantum computers are realized will jeopardize the security of public key cryptosystems which are widely deployed within communication protocols, digital signing mechanisms, authentication frameworks, and more. To avoid this, NIST has actively led a PQC standardization effort since 2016, leveraging a large and international research community.
On January 31-February 1, 2019, the Computing Community Consortium (CCC) held a workshop in Washington, D.C. to discuss research challenges associated with PQC migration. Entitled, "Identifying Research Challenges in Post Quantum Cryptography Migration and Cryptographic Agility", participants came from three distinct yet related communities: cryptographers contributing to the NIST PQC standards effort, applied cryptographers with expertise in creating cryptographic solutions and implementing cryptography in real-world settings, and industry practitioners with expertise in deploying cryptographic standards within products and compute infrastructures. Discussion centered around two key themes: identifying constituent challenges in PQC migration and imagining a new science of "cryptographic agility".