1. Experiences with Massive PKI Deployment and Usage Daniel Kouřil, Michal Procházka Masaryk University & CESNET Security and Protection of Information 2009

2. Public Key Infrastructure Asymetric cryptography Each user and service owns key-pair X.509 digital certificates PGP not suitable Certification Authority (CA) Network of Registration Authorities (RA) Relying parties

3. Distributed environments Ithanet project Network for medical research in Mediterranean countries Users were physicians with little knowledge about computers Grid infrastructure Facilitates collaborations, resource sharing support of research Basic services provided by grid operator Easy establishment of secure communication

4. PKI in large-scale environment PKI is good candidate for authN in large infrastructures Scalability Several aspects to be considered and addressed Operators Users General PKI not tied with applications

5. Operating PKI CA establishment is not technical problem Building trust is crucial Many administrative problems Proper applicants authentication Protection of signing keys Proper revocation requests handling Long-term support Incident resolution cooperation … CAs publish their policies

6. International Grid Trust Federation Easing orientation for relaying parties CA managers, identity providers, large relying parties involved IGTF builds a federation of trusted CAs approving procedures and minimal requirements reviews the CA policies (CP/CPS) Flat model – no root IGTF CA Unified name space for subject names User is uniquely identified by their subject name

7. Revocation checks Revocation is a must Often neglected by administrators or applications Its impossible to check CRLs with Firefox Certification Revocation Lists (CRLs) Online Certificate Status Protocol (OCSP) Overhead Latency penalty for online checks Large amount of data represented by aggregated CRLs transfers

8. Obtaining certificates The process consists of two phases Generating key-pair Identity vetting at RA Crucial for users perception Crucial for security of credentials

9. Online CAs Normal web page with simple form Registration is done first Browser is key component Perform cryptographic operations Communicates with CA Receives and stores new certificate New requirements Signing machine of CA is exposed Trust in browser

10. Online CAs in Identity Federations Identity federations leverage existing users management systems Access to internal systems of institution Users dont need additional credentials to access new services Online CA connected to federation No need for personal visits at RA

11. Private Key Protection Users dont protect their private keys Weak passphrases, file permissions Cant be checked by PKI operators Ideally not handled directly by users – transparent PKI Key repositories Specialized service maintaining keys for users Smart cards User support is difficult in general PKI

12. Conclusions Several aspects to address to operate secure PKI Established set of trusted CAs available General CAs, not tied with a particular application Keep users away from their private keys :-)

13. Backup slides

14. Single Sign-On User authenticates just once Proxy certificate Issued by user Only short-lived Standard X.509 short-lived certificates Issued by an on-line CA Can be obtained automatically after login