Liaison statement
LS on ITU-T SG17 work on quantum-safe PKI

State Posted
Posted Date 2017-09-13
From Group ITU-T-SG-17
From Contact Jean-Paul Lemaire
To Groups ipsecme, lamps
To Contacts David Waltermire
Tero Kivinen
Russ Housley
CcDavid Waltermire
IP Security Maintenance and Extensions Discussion List
Limited Additional Mechanisms for PKIX and SMIME Discussion List
Russ Housley
Scott Mansfield
Kathleen Moriarty
Tero Kivinen
Eric Rescorla
Response Contact
Purpose For information
Attachments sp16-sg17-oLS-00068
ITU-T Study Group 17 is pleased to inform you that in our August/September 2017 meeting we agreed to start work on the inclusion of a proposal to include optional support for multiple public-key algorithms in Recommendation ITU-T X509 | ISO/IEC 9594-8.

The industry is preparing ICT systems to be resistant to attacks by large-scale quantum computers in addition to more sophisticated attacks by conventional computing resources. Proposed was an optional feature to the X.509 certificate that provides a seamless migration capability to existing PKI systems, and is completely backwardly compatible with existing systems.

While public-key key establishment algorithms are typically negotiated between peers and are generally fairly simple to update, the authentication systems typically rely on a single digital signature algorithm which are more difficult to update. This is because of the circular dependency between PKI-based identity systems and the dependent communication protocols. In order to update a PKI system, one would typically need to create a duplicate PKI system that utilizes a new digital signature algorithm and then migrate all the dependent systems one by one.

This proposal eliminates the need to create such duplicate PKI systems by adding optional extensions to contain alternate public key and alternate signature, and a method for the CA to sign certificates using a layered approach to ensure that every attribute is authenticated by both signatures. The resulting certificate, while containing new quantum safe public key and signature, can still be used by existing systems relying on the classic public key and signature.