Public key infrastructure (PKI) uses public and private key cryptography and digital certificates to provide security services like authentication, non-repudiation, and data integrity. A PKI system uses certification authorities to validate users' identities and issue digital certificates that bind public keys to those identities. These certificates allow users to securely exchange information and digitally sign documents online through services like SSL/TLS and S/MIME. Smart cards can serve as portable devices for storing users' private keys and certificates to enable strong authentication on untrusted devices.

1. Public Key Infrastructure and Applications Svetlin Nakov Sofia University “St. Kliment Ohridski” E-mail: [email_address] Nikolay Nedyalkov Latona Development E-mail: [email_address]

4. Multiple Security Issues Privacy Integrity Authentication Non-repudiation Interception Spoofing Modification Proof of parties involved

15. Certificate Life Cycle Key pair generated Certificate issued Key pair in use Private key compromised Certificate revoked Certificate expires Key pair lifetime exceeded? New key pair generated Re-certify

27. Microprocessor based smart card

30. Smart card application example: Digital Signature

32. ISO 7816 vs USB

36. Using PKI Certificates in Outlook (1) Open Outlook . Select Tools from the main menu then choose Options from the drop-down menu. 1

37. Using PKI Certificates in Outlook (2) Click on the Security tab. 2

38. Using PKI Certificates in Outlook (3) Click the Settings button. 3

39. Using PKI Certificates in Outlook (4) In the Security Settings Name field, enter a name for the new Security Setting . Type S/MIME in the Secure Message Format field. Click the Choose button next to the Signing Certificate field. 4

40. Using PKI Certificates in Outlook (5) Click on the certificate issued by C3 Mail CA . This is your Email Signing certificate. Click OK . 5

41. Using PKI Certificates in Outlook (6) Choose SHA1 from the Hash Algorithm drop down menu. Click on the Choose button next to the Encryption Certificate field. 6

42. Using PKI Certificates in Outlook (7) Click on the certificate issued by C3 Mail CA . This is your Email Encryption certificate. Click OK . 7

43. Using PKI Certificates in Outlook (8) Choose 3DES from the Encryption Certificate drop down box. Check all 3 boxes in the Change Security Settings window. Click OK . 8

44. Using PKI Certificates in Outlook (9) Click the Apply button then click OK . 9

45. Questions?