Cloudflare explores post-quantum designs for private web-access tokens

Cloudflare researchers described possible post-quantum designs Friday for privacy-preserving web credentials, outlining work intended to keep abuse controls useful as cryptographic threats evolve. The post examines blind signatures and a proposed system called MOLE.

According to Cloudflare, the company drew a distinction between token forgery and privacy. It said Privacy Pass still relies on classical cryptography that a sufficiently capable quantum attacker could break, while unlinkability between a token’s issuance and redemption does not depend on resisting that attack.

According to Cloudflare, the post identifies the size and engineering cost of post-quantum alternatives as obstacles. It presents a research direction rather than announcing that a production replacement for current tokens has been deployed.

What we know / what we don't

What we know

• Cloudflare researchers described possible post-quantum designs Friday for privacy-preserving web credentials, outlining work intended to keep abuse controls useful as cryptographic threats evolve. The post examines blind signatures and a proposed system called MOLE.
• According to Cloudflare, the company drew a distinction between token forgery and privacy. It said Privacy Pass still relies on classical cryptography that a sufficiently capable quantum attacker could break, while unlinkability between a token’s issuance and redemption does not depend on resisting that attack.
• According to Cloudflare, the post identifies the size and engineering cost of post-quantum alternatives as obstacles. It presents a research direction rather than announcing that a production replacement for current tokens has been deployed.

What we don't know

• The cryptographic constructions were not independently audited for this draft; proposed security properties are attributed to the researchers.

The source record

Sources

1. Cloudflare cryptography research post

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