Geo Key Management

4 posts · Sep 2014 – Mar 2023

What this trail covers

Cloudflare's Geo Key Manager has evolved to v2, replacing its identity-based broadcast encryption and revocation scheme with Attribute-Based Encryption (ABE). This addresses limitations in flexibility, performance, and manual key rotation of the original system. GeoV2 allows for more dynamic and granular access control policies based on attributes, avoiding a single point of failure and simplifying the management of keys across a growing global network. The implementation of ABE is open-sourced.

All Cloudflare trails

Mar 2023Protect your key server with Keyless SSL and Cloudflare Tunnel integrationThis post announces an enhancement to Keyless SSL by integrating it with Cloudflare Tunnels. Previously, key servers for Keyless SSL required a publicly queryable DNS record, exposing them to potential attacks. The new integration allows customers to use Cloudflare Tunnels to connect to their key servers through a secure, private channel, eliminating the need to expose the key server's IP address to the public internet. This strengthens the security of key servers by making them accessible only to Cloudflare.
Jan 2023Inside Geo Key Manager v2: re-imagining access control for distributed systemsThis post details the evolution of Cloudflare's Geo Key Manager from v1 to v2. GeoV1 used identity-based broadcast encryption and revocation, which proved inflexible for evolving customer data localization needs and operational requirements. GeoV2 replaces this with Attribute-Based Encryption (ABE), offering dynamic access control policies based on attributes. This change simplifies key management, improves performance, and avoids a single point of failure by allowing for more granular control over key distribution based on geographic location and other attributes. The post also includes an open-source implementation of ABE in the CIRCL library.
Dec 2022A new, configurable and scalable version of Geo Key Manager, now available in Closed BetaIntroduced a new, configurable, and scalable version of Geo Key Manager, now in Closed Beta. This version moves from a fixed set of regions (US, EU, Highest Security) to a policy-based system allowing customers to define custom geo-restrictions using country codes and regions (e.g., 'country:US or region:EU', 'region: EU and (not country: FR)'). It supports over 30 countries and regions and is designed to be attribute-based, enabling future policies based on compliance standards like FedRAMP or ISO 27001. The system now dynamically scales with network expansion and includes redundancy restrictions to prevent availability issues. Performance impact analysis for latency is under development.
Oct 2021Geo Key Manager: Setting up a service for scaleThis post details the evolution of Cloudflare's Geo Key Manager system to address scaling challenges. It describes the original architecture involving Keyless SSL, identity-based encryption, and a Rust service 'keynotto' for key signing, and a Go service 'gokeyless'. The post highlights issues like head-of-line blocking in keynotto due to sequential processing on a single connection and performance degradation caused by remote key signing latency for Geo Key Manager requests. It also discusses the performance comparison between Go and Rust implementations, and the impact of switching gokeyless to BoringCrypto for FedRAMP certification. The post details the investigation into TLS handshake failures in Melbourne, tracing them to a new zone with high API traffic and Geo Key Manager enabled, and the subsequent performance degradation affecting unrelated zones due to the architectural limitations.
Oct 2021Pairings in CIRCLThis post introduces pairing-based cryptography as a new component within the CIRCL library, detailing its mathematical properties and applications. It explains how pairings enable efficient three-party Diffie-Hellman key exchange and Identity-Based Encryption (IBE). The post also highlights the use of pairings in zk-SNARKs, drand, and Ethereum's BLS signatures, and explains how Cloudflare uses pairings for Geo Key Manager's compact broadcast and negative broadcast schemes.
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Sep 2017Geo Key Manager: How It WorksThis post details the initial architecture of Geo Key Manager, which builds upon Keyless SSL. It introduces a novel cryptographic access control mechanism using Identity-Based Broadcast Encryption (IBBE) and Identity-Based Revocation (IBR) to allow customers to control the geographic locations where their private SSL keys are stored. The system uses identity-based encryption where a datacenter's identity is its public key, and access is controlled by encrypting keys to specific regions and locations, with the ability to exclude specific datacenters.
Sep 2017Introducing the Cloudflare Geo Key ManagerIntroduced Geo Key Manager, a feature allowing customers to restrict the physical location where their SSL private keys are stored. This addresses geopolitical concerns and regulatory mandates by enabling key distribution to specific subsets of Cloudflare's data centers. Options include 'Everywhere' (default), 'U.S. Only', 'E.U. Only', and 'Highest Security Data Centers', with detailed descriptions of the physical security requirements for each tier. The post also discusses the performance implications of not having keys locally accessible, primarily affecting the first HTTPS request to a data center without the key, due to the need for session key negotiation via Keyless SSL.
Sep 2014One More Thing: Keyless SSL and CloudFlare's Growing NetworkIntroduces Keyless SSL as a strategy to expand Cloudflare's global network by allowing SSL services without storing private keys in all edge data centers. This enables expansion into facilities with less stringent security requirements and addresses geopolitical concerns by allowing customers to specify key storage regions.
Sep 2014Keyless SSL: The Nitty Gritty Technical DetailsThis post details the technical implementation and security considerations of Cloudflare's Keyless SSL, which allows customers to use their private SSL keys without handing them over to Cloudflare. It explains the TLS handshake process (RSA and Diffie-Hellman), the dual goals of confidentiality and authentication, and the technical details of how Keyless SSL achieves these goals by keeping the private key on the customer's origin server while enabling Cloudflare's edge to perform SSL termination.
Sep 2014Announcing Keyless SSL™: All the Benefits of CloudFlare Without Having to Turn Over Your Private SSL KeysIntroduced Keyless SSL, a novel solution that enables SSL termination in the cloud without requiring Cloudflare to possess the customer's private SSL keys. This was achieved by splitting session signing from the rest of the SSL handshake, allowing an agent on the customer's infrastructure to perform the private key operations while the remote Cloudflare server handles the connection. This addressed the security concerns of financial institutions regarding key compromise and enabled them to leverage cloud-based scalability for SSL termination.