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Is an Internet PKI the Right Approach?

Eric OsterweilJoin work with:

Dan Massey and Lixia Zhang

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Life in the Internet The Internet is a uniquely challenging environment

to deploy systems because: It is immense It is has a highly diverse makeup Its constituent components are constantly in flux and are

administered by independent authorities As a result, systems must be designed to tolerate:

Constant configuration errors, incremental deployments (which may take years), and diverse opinions on who is trustworthy

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Problems The Internet’s heterogeneity makes it difficult for

systems to rely on being fully deployed Systems must function while being incrementally deployed,

broken, etc. Internet parties are notorious for not agreeing whom

to trust Choosing “trusted authorities” often sparks debate

Successful Internet Systems tend to be very tolerant of misconfigurations and multiple independent opinions Like DNS and BGP

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DNS has tried Crypto The DNS Security

Extensions (DNSSEC) RFCs 4033-4035

Approach: a PKI following DNS’ hierarchy A single “island of security”

rooted at DNS’ root zone Everyone trusts the root

DNSSEC uses public key cryptography Each zone signs all of its own data, and the keys for its children zones

too By bootstrapping with a single key (trust-anchor) from the root, all

keys can be recursively learned

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DNSSEC Status Today Only 10,459 secure zones have deployed

Only about 900 seem to be production Root zone has not signed

Rather than a single island there are 662 97.3% are singleton (isolated) zones This means 662 trust-anchors would be needed How can the keys for this many independent zones by globally

verified? Operational management of cryptography has reduced

its effectiveness Monitoring has shown that rapid re-signing leaves roughly 19.8%

of data vulnerable to replays

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A New Concept: Public-Space Trust doesn’t have to be predicated on the status of

deployments Track public actions instead

Public actions can be subjected to scrutiny Anyone may publish data

Who has published data, its consistency, and its history can let each individual judge its veracity Misbehavior like Man-in-the-Middle (MITM) attacks cannot be

denied when done in the Public-Space Global consistency can be evaluated by polling from

multiple locations Local MITM attacks can be globally refuted in public

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Public-Space Systems We record what is done rather than mandate

what operators must do / who they must trust SecSpider

DNSSEC key learning Because DNSSEC’s PKI has not evolved

BGP-Origins BGP prefix attestation system Because BGP does not have a PKI

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SecSpiderhttp://secspider.cs.ucla.edu/ Learns keys from many

global pollers Keys are tracked over time Serves globally consistent keys Anyone can verify keys they

have looked up Adversaries must compromise all pollers to subvert the

Public-Space Results are not provably correct but practically effective Data owners check the Public-Space for correctness

SecSpider is not a data authority We are formalizing this approach to achieve security through

publicity

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BGP-Originshttp://www.bgp-origin.org/ BGP allows any Autonomous System (AS) to

announce that it hosts any IP addresses (prefixes) ASes send out false announcements sometimes

Pakistan hijacked YouTube by announcing its prefixes BGP-Origins uses global monitors (RouteViews) and

tracks which ASes have announced which prefixes Also, any user can attest to a prefix-AS binding

Operators could have attested to the proper binding of YouTube’s prefixes to avoid the hijack

Users decide whom to trust and discard attestations from unknown parties

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Ongoing Work Are conventional PKIs a good fit for the Internet?

Operational groups disagree on many “trust” issues Public-Space applications are maturing

Increasing usage is coming with ongoing publicity at operational meetings

Public-Space can be a substitute for the missing PKI in DNSSEC’s partially deployed state Users can verify data against what is in the Public-Space

With no PKI for BGP, the Public-Space uses real-world trust that already exists between operators Addresses attacks and misconfigurations

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Thank YouQuestions?