Public Key Infrastructure 101 Mark L Silverman CISSP

Public Key Infrastructure 101 Mark L. Silverman, CISSP DHHS PKI Program Manager December 7, 2005

A Riddle You are standing in a room. On the wall are three toggle light switches, clearly marked on/off and currently all in the off position. One of the switches controls a normal 100 watt table lamp, located in the room next door. It does not matter what the other two switches control. From your room, there is no way that you can see the light from the lamp (no mirrors, extension cords, etc. ). By entering the room with the lamp only once, how can you determine which switch controls the lamp? 2

Today’s Objectives n Why PKI n n PKI Tutorial n n Legislative Requirements E-Authentication HSPD-12 Cryptographic Overview SMIME and Digital Signatures PKI Components and Operations HHS PKI Overview n n n Certificate Issuance System Certificate Validation Service Obtaining HHS Digital Certificates 3

Today’s Objectives (continued) n Microsoft Outlook n n n Signing with Adobe 7. 0 Signing a MS Word Document Managing Certificates n n n Configuring Sending signed/encrypted email Receiving signed/encrypted email Backup (Export) Copy/Restore (Import) Web based authentication and signatures (LRA) 4

Why PKI? 5

Extended Trust PKI is the only technology that extends trust beyond the enterprise with no a priori relationship between the trusted parties. 6

President’s Management Agenda Agencies will undertake a Federal Public Key Infrastructure (PKI) to promote digital signatures for transactions within the federal government, between government and businesses and between government and citizens. 7

Federal PKI Drivers Ø Government Paperwork Elimination Act (GPEA) 1998 Requires Agencies to accept transactions, and maintain records electronically, when practicable Ø Electronic Signatures in Global and National Commerce Act (E-Sign) 2000 An electronic signatures can not be denied legal status. Ø Ø E-Government Act of 2002 Achieve interoperable implementation of electronic signatures for appropriately secure electronic transactions with Government. OMB to oversee implementation of electronic Government. Memorandum Streamlining Authentication and Identity Management (OMB 7/03/03) Agencies will acquire PKI services from shared service providers (see also OMB M 05 -05) E-Authentication Guidance for Federal Agencies (OMB M-04 -04 - 12/16/03) Ensure that authentication processes provide the appropriate level of assurance. SP 800 -63 - Electronic Authentication Guideline Policy for a Common Identification Standard for Federal Employees and Contractors (HSPD-12 – 8/27/04) Smartcard ID badge for logical access to Agency IT systems. FIPS 201 - Personal Identity Verification (PIV) of Federal Employees and Contractors 8

E-Authentication OMB M-04 -04 Authentication Mechanism Potential Impact of Authentication Errors 1 2 3 4 Inconvenience, distress, reputation Low Mod High Financial loss or agency liability Low Mod High Harm to agency program or public interests -- Low Mod High Unauthorized release of sensitive information -- Low Mod High Civil or criminal violations -- Low Mod High Personal safety -- -- Low Mod PKI level 3 & 4 es ess c o r s. P s e usin User ID Password level 2 Anonymous Access level 1 B Web Pages Time Card Patient Data E-Authentication Risk Assessment: http: //www. cio. gov/eauthentication/documents/eraguide. pdf 9

Homeland Security Presidential Directive 12 Policy for a Common Id Standard for Federal Employees and Contractors Ø Mandates new Federal ID Badge that is: § § Ø Ø Based on sound criteria to verify an individual employee’s identity Resistant to fraud, tampering, counterfeiting, and terrorist exploitation Rapidly verified electronically Issued only by providers whose reliability has been established by an official accreditation process Agencies shall, to the maximum extent practicable, require the use of identification by Federal employees and contractors that meets the Standard in gaining physical access to Federally controlled facilities and logical access to Federally controlled information systems. FIPS 201 - Personal Identity Verification of Federal Employees and Contractors þ PIV-1: Identity proofing process þ PIV-2: Smartcard ID Badge October 2005 October 2006 10

FIPS 201 PIV Process Authori ze Register Issue Use Local sponsor fills out applicant’s badge request form, which is then approved by an Authorizing Official and forwarded to the Registration Authority checks applicant’s identity documents; obtains applicant’s photograph, fingerprints and other background check data. Background check must be completed before badge Issuing Authority verifiesissuance. applicant against PIV-1 Oct 05 registration data. Then creates and issuesbiometrics badge. Badge loaded with applicant’s (fingerprints and photograph), PIN and PKI PIV-2 certificate information. Badge accepted / electronically validated by all Agencies. Oct 06 PIN / biometrics used for stronger physical authentication. PKI certificates used for logical authentication to IT systems. Each step must be performed independently by different people. Entire process and support systems must be accredited. 11

Tutorial 12

Foundations of PKI 13

Cryptography n Science of secret (hidden) writing kryptos – hidden n graphen –to write n n Encrypt / encipher n n Convert plaintext into ciphertext Decrypt / decipher n Convert ciphertext into plaintext 14

Early Examples of Cryptography n Spartan Scytale – fifth century BC n Julius Caesar (49 BC) substitution cipher Plaintext: 3 characters Ciphertext: ET TU BRUTE Shift Algorithm HW WX EUXWH 15

Symmetric Key Cryptography Same key used to encrypt and decrypt Alice ciphertext Dear Bob: I am leaving you. Goodbye forever. Alice n n encrypt 0111001001 1100111001 001110000111111 Dear Bob: decrypt I am leaving you. Goodbye forever. Alice Computationally fast Data Encryption Standard (DES) n n n Bob Block Cipher, 56 bit key Triple DES 112 bit key Advanced Encryption Standard (AES) n n n Rijndael Algorithm Belgian cryptographers, Joan Daemen and Vincent Rijmen. 128, 192, 256 bit keys 16

Symmetric Encryption Issues n n Key (shared secret) vulnerable to discovery Need to share a unique secret key with each party that you wish to securely communicate n n N * (N – 1) Problem Key management becomes unmanageable 17

Asymmetric Key Cryptography n Two mathematically related keys n n Unable to derive one from the other Based upon hard problem n n Public Key Cryptography n n Bob Dear Carol: Alice is gone. Now we can be together RSA - Integer Factorization (large primes) Diffie-Hellman - Discrete Logarithms ECES - Elliptic Curve Discrete Logarithm One public key published for all to see Other is private key kept secret by owner Works both ways Can encrypt with either key – decrypt with the other encrypt 0111001001 1100111001 001110000111111 decrypt Dear Carol: Alice is gone. Now we can be together Love, Bob Carol’s Public Key Carol’s Private Key Bob: Leave me alone! Carol Bob: decrypt 0111001001 1100111001 001110000111111 encrypt Leave me alone! Carol 18

Asymmetric Advantages n n No shared secret key Public key is public n n n Private key known ONLY to owner n n Can be freely distributed or published Key management is much easier Less vulnerable, easier to keep secret Supports Non-repudiation n Encrypt with sender’s private key (only known by sender) Sender can not deny sending message Basis for digital signatures 19

Electronic Signatures Electronic Signature != Digital Signature Electronic Signatures in Global and National Commerce Act (E-Sign) defines: The term ‘‘electronic signature’’ means an electronic sound, symbol, or process, attached to or logically associated with a contract or other record and executed or adopted by a person with the intent to sign the record. 20

Digital Signatures A digital signature is a a type of electronic signature. It is a hash of a document encrypted with the author’s private key Sue Dear Mr. Bob: We have asked the Court to issue a restraining order against you to stay away from Carol. Sincerely, Sue Yew Dewey, Cheatam & Howe, Law Firm Sue’s Private Key Hash Function Sincerely, Hash Value 0 F 47 CEFF AE 0317 DB AA 567 C 29 We have asked the Court to issue a restraining order against you to stay away from Carol. Sue Yew Dewey, Cheatam & Howe, Law Firm encrypt 0101011110000110101 101111010111 Digital Signature 21

Validating a Digital Signature 1. Re-compute the hash value 2. Obtain the author’s public key 3. Decrypt the original hash 4. Compare hash values – if match signature is valid Dear Mr. Bob: 0 F 47 CEFF AE 0317 DB AA 567 C 29 We have asked the Court to issue a restraining order against you to stay away from Carol. Sincerely, Sue Yew Dewey, Cheatam & Howe, Law Firm 0101011110000110101 101111010111 decrypt 0 F 47 CEFF AE 0317 DB AA 567 C 29 Hash proves document unchanged integrity Public key proves authorship non-repudiation Sue’s Public Key 22

Asymmetric Issues n More computationally intensive n n 100 x symmetric encryption Generally not used to encrypt data n n Encrypt symmetric key (S/MIME) SSL session key 23

SMIME Encryption Encrypted email uses the recipient's public key Bob Dear Carol: I am still hoping when I get out of prison we can be together. Love, Bob A 032 F 17634 E 57 BC 43356 743212 b 9 c 9 8 FA 2917342 5633 A 22201 807732 ECF 1 3344567520 ABCE 4567 CD encrypt Carol's Public Key 01110 11001 0011100001 Carol decrypt Carol's Private Key 24

Source of Public Key n n Keys can be published anywhere Attached as a signature to e-mail n Pretty Good Privacy (PGP) -----BEGIN PGP SIGNATURE----Version: PGP 7. 0. 4 i. QCVAw. UBOx 6 Sgo. FNSxz. KNZKFAQGK+g. P 6 An. CVgh. Zqb. L 3+r. M 5 JMSqo. C 5 OEYIkbv. YZN 92 CL+YSCj/Ekd. Znjx. Fm. U 9+w. Gs. Wi. Cwxvs/Tz. SX 6 SZxlp. G 1 b. HFKf 0 OPu 7+JEf. J 7 J 5 z c. PCSqb. FXi. Xzmuk. Ml 5 KNx 0 p 0 ve. IDW 4 Dmwle. Dpkmh. T 05 qn. Cheweo. Nyv. TSzf. A 1 TGe. Ll mpj. Bi 6 z. Uji. Y= =Xq 10 -----END PGP SIGNATURE----- 25

But… n How do you know for sure who is the owner of a public key? 26

Public Key Infrastructure (PKI) provides the means to bind public keys to their owners and helps in the distribution of reliable public keys in large heterogeneous networks. NIST The set of hardware, software, people, policies and procedures needed to create, manage, store, distribute, and revoke Public Key Certificates based on public-key cryptography. IETF PKIX working group PKI is electronic identity management! 27

X 509. V 3 Digital Certificate n Issued by a TRUSTED third party Certificate Authority (CA) n n n Creates and digitally signs Certificates Issues Certificate Revocation Lists (CRLs) or Online Certificate Status Protocol (OCSP) Identity Proofing done by Local Registration Authority (LRA) 28

PKI Users n Subscribers n Entity who obtains certificates from a CA n n Person, device, application, etc. Owns private key associated with public key in certificate n n n Non-repudiation requires only subscriber has access to private key CA may escrow private key used for encrypted email Owner must protect private key n n n Password Safer with hardware token / smart card Relying Party n n Entity who receives digital certificate Trusts CA who attests to certificate holder’s identity 29

How Certificates are used Subscriber signs message to A Private key Relying Party A Get CRL to Validate Certificate 010111 102101 Relying Party B encrypts message to Subscriber Directory Get Subscriber's Certificate 30

SSL Server Authentication 3 Trust Issuing CA? 1 2 4 CRL Validate Certificate 6 5 WWW 7 1. Client sends https request to server 2. Server sends its certificate to the client 3. 4. 5. 6. Client decides if certificate (and issuing CA) is trustworthy Client validates certificate Client sends to server session key - encrypted with server’s public key Server decrypts session key with its private key 7. Client – Server transactions are now encrypted with session key 31

Ever See this? What do you do? 32

Trusted Third Party PKI is built upon the concept of the trusted third party (i. e. , CA) But, who are you going to trust? 33

Who do you Trust? n Everyone trusts their own CA (trust anchor) n Trust all certificates issued by their CA CA George n Martha Clark Single CA model does not scale well n Difficult to manage across large or diverse user communities 34

Hierarchical PKI n CAs have superior-subordinate relationships n n n Higher level CAs issue certificates to subordinate CAs Subordinate CA issues certificate to subscriber Forms a certification path (aka certificate chain) n n Chain of certificates from subscriber to root CA Root CA is top-level, self-signed (i. e. , certified) CA 35

Certificate Chain Self Signed Root CA Certificate Info Root CA's Private Key Root Signature Sub CA Subordinate CA Certificate Info Root CA's Private Key Root Signature Subscriber Certificate Info Subordinate CA's Private Key Sub. CA's Signature Text Document Subscriber's Private Key Subscriber's Signature 36

Relying Party Certification Path A relying party builds a certificate path from the other subscriber to the relying party’s trust anchor Green CA Yellow Blue Gold Red Mark Phyllis Mark gets cert from Phyllis 1. Phyllis's cert signed by Red CA 2. Red's cert signed by Blue CA 3. Blue's cert signed by Green CA is Mark's trust anchor, therefore Mark trust's Phyllis's cert 37

What about other CAs? How do you know if you can trust the CA? Then, how much do you trust them? 38

Trust Lists Commercial CAs often come pre-loaded Why and how much do you trust a CA? 39

PKI Policies n Certificate Policy (CP) n n n High level document Describes security policy for operating the CA Defines roles and responsibilities n n Certification Practices Statement (CPS) n n How CA will be managed How registration will be performed (i. e. , identity proofing requirements) How subscribers use and handle their certificates and keys Detailed document Describes mechanisms and procedures followed by CA to meet the requirements of their CP Effectively the CA's operations manual. Together, Determines Assurance Level n How much you should trust the CA’s certificates 40

However…. Users generally don’t examine policies Most users just click YES to trust CA for expediency 41

Cross-Certified PKIs ± Peer-to-peer trust relationship n n J Between CAs or hierarchical PKI root CAs review polices and issue certificates to each other Advantages n CAs are organizationally independent n n Blue CA Gold CA Red CA Have independent policies CA compromise does not effect others Disadvantages n Green CA Can form a MESH PKI CA needs to maintain multiple relationships with other CAs Hard to build certification path n n Multiple possible paths Loops and dead ends Mark Phyllis 42

Bridge PKI Architecture n Bridge is trust arbitrator n n Only cross-certifies with other CAs Relationships still peer-to-peer n n n Bridge CA Bridge is NOT a root CA Certification path construction is much easier Bridge does all policy management Blue CA Green CA Gold CA Red CA Mark Phyllis Less work for the CAs Maintains list of revoked CAs (CARL) 43

Federal Bridge Certificate Authority Illinois PKI DOD PKI NASA PKI NFC PKI Health Care BCA Hospital PKI Higher Ed BCA CANADA PKI University PKI All trust relationships handled by bridge CA 44

In HHS CA we Trust DST is cross-certified with the FBCA DST root is preloaded in browser/outlook trust lists DST/ACES part of Federal PKI HHS Certificates issued by Digital Signature Trust, (a commercial CA under GSA ACES) Trusted TLS (SSL) certificates also available 45

HHS PKI Program 46

Project Goals Maintain and operate a public key infrastructure (PKI) to issue digital certificates to HHS entities (e. g. , staff, applications, devices). PKI CAI Maintain and operate a certificate acceptance infrastructure (CAI) to validate the certificates that we receive from inside and outside HHS. PKE Assist in PK-enabling (PKE) HHS business processes. 47

Certificate Issuance System Subscriber goes to registration web site enters MS credentials AD record is downloaded Subscriber selects pass phrase Directory Record Login Pass phrase Subscriber’s data stored in RA database Subscriber prints (bar-coded) registration form Subscriber takes form to LRA scans form, validates information and approves subscriber Email sent to subscriber Subscriber data Data RA App SSL Border Directory Approval Subscriber data Subscriber follows URL to web page and enters their pass phrase Validated subscriber is redirected to CA along with subscriber’s data Certificates downloaded to subscriber’s browser and posted into Border Directory (and subsequently imported into AD) AD SSL Pass phrase 48

Certificate Validation Service 4 3 b 2 1 PKE 3 d 3 a 1. Application receives certificate 2. PKI-enabled applications calls CAM 3. CAM validates certificate with: a. HHS CA (DST) b. Other ACES CAs c. Other CAs directly trusted by HHS d. Other CAs trusted through FBCA 3 c HHS PKI Trusted PKI OTHER PKI 4. CAM logs validation to meet GPEA/NARA electronic records requirements 49

Putting it all together Other PKI FBCA CRLs TLS Reg Cross-Certification Border Directory Staff Reg Certificate Status Information to other PKIs + SSL Subscriber Certificate Records Archiv e Subscriber Encrypted Email Signed Documents From other PKIs Relying Party A Certificate Status + Digitally Signed Document Relying Party B Certificate Status Signature Validation records 50

Obtaining your HHS Certificate 51

Request Your Certificates 52

Identify Yourself 53

Active. X Requirements 54

Review Steps 55

Identify your Employer 56

Verify Your Information If incorrect, see your local system administrator 57

Pick One-Time Pass phrase You will need this pass phrase to get your certificates in the last step 58

Download/Print Request Form Click here to download form 59

PKI Certificate Request Form Contractors need customer’s signature (e. g. , PM, AO) Notary information is ONLY collected if can not appear inperson before LRA Second form of ID is needed ONLY if Federal badge doesn’t have unique ID number Don’t sign / date until you are before an LRA Photocopy Government picture ID onto form 60

Take Completed Form to LRA 61

Enabling Active. X Tools -> Internet Options -> Security 62

Email Notification Click on this URL to obtain your certificates 63

Enters Pass Phrase Enter pass phrase If you forgot your passphrase, you will need to repeat the form creation and LRA process 64

Install Active-X Module Click YES to install. Some “locked down” desktops may (currently) require system admin. support 65

Review & Accept Subscriber Agreement Check this box 66

Download Instructions Click link to download PDF Click box Then click next 67

Begin Retrieval Process Click 68

Microsoft Warning Click YES 69

Change Security Level You MUST click here to set security level to HIGH in order to password protect your private key 70

Set Security Level to High Check HIGH Then click Next 71

Set Password for Private Key You must REMEMBER this password. It can not be reset by an administrator. 72

Click OK to Save Setting After setting security level to HIGH You may now click OK 73

Processing. . . 74

Review Your Certificates 75

Download Encryption Certificate 76

Repeated Microsoft Warning Click YES 77

Repeat Setting Security Level to High 78

Set Encryption Password You may use the SAME password you entered for your signing Certificate 79

Certificate Download Complete 80

Configuring Outlook Tools → Options 81

Tools → Options → Security → Settings… Security tab Click Settings 82

Specify Signing Certificate Specify ANY name you like Click Choose 83

Select DST ACES Certificate If more than one pick Certificate issued by DST ACES Federal Employee CA 84

Specify Encryption Certificate Click Choose 85

Publish to GAL 86

Enter Certificate Password Do NOT Check You will be prompted to enter your password each time you use your certificate 87

Using Your Certificates 88

Sending Signed/Encrypted Email 89

Message Options If using Microsoft Office Word to edit e-mail messages 90

Security Settings 91

Send Enter PKI private key password to sign email NEVER 92

Receiving Secure Email 93

Click Ribbon for Details Lock shows Message was encrypted 94

Add Buttons to toolbar Uncheck to set to default message editor 95

Configure Message Editor Buttons automatically migrate to Word editor as well 96

Adobe 7. 0 97

Create Adobe Signature 98

Position Adobe Signature 99

Select Certificate 100

Specify Reason for Signature 101

Private Key Password NEVER 102

First Time – May not be Trusted 103

Enable Windows Trust 104

Validate Signature Right Click 105

Add Trusted CA (Macintosh) Right Click 106

Signing a Word Document 107

Signed Document Double Click 108

Managing Your Certificates 109

Export (backup/move) 110

Pick First Certificate 111

Specify File and Password Filename Password This is a NEW password to protect the FILE! 112

Enter Certificate Password This is the OLD password used to protect your private key 113

Repeat for Second Certificate 114

Import Certificate Filename and password from export Must enter a name. Use any name you like. 115

Set Security Level to High Import/export is way to password protect private key if you failed to set security level when initially obtaining your certificates. 116

Create New Password This is the password to protect your private key. 117

Repeat for Second Certificate 118

Internet Explorer 119

Tools → Internet Options → Content… Content Tab Click Certificates…. 120

Can Export/Import/Delete 121

LRA Subscriber Registration 122

HHS PKI LRA Home Page 123

Certificate Authentication 124

First Time Download 125

LRA Management Page 126

Collect Registration Data 127

Approve Request 128

Registration Complete 129

Questions Answers: http: //www. pki. hhs. gov http: //www. pki-page. org/ http: //www. rsasecurity. com/rsalabs/faq/ http: //csrc. nist. gov/pki/ mls@nih. gov 130