public key infrastructure 101
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Public Key Infrastructure 101
Mark L. Silverman, CISSPDHHS PKI Program Manager
December 7, 2005
2
A Riddle
You are standing in a room. On the wall are threetoggle 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 waythat you can see the light from the lamp (no mirrors, extension cords, etc.).
By entering the room with the lamp only once, howcan you determine which switch controls the lamp?
3
Today’s Objectives
Why PKI Legislative Requirements E-Authentication HSPD-12
PKI Tutorial Cryptographic Overview SMIME and Digital Signatures PKI Components and Operations
HHS PKI Overview Certificate Issuance System Certificate Validation Service Obtaining HHS Digital Certificates
4
Today’s Objectives (continued)
Microsoft Outlook Configuring Sending signed/encrypted email Receiving signed/encrypted email
Signing with Adobe 7.0 Signing a MS Word Document Managing Certificates
Backup (Export) Copy/Restore (Import)
Web based authentication and signatures (LRA)
5
Why PKI?
6
Extended Trust
PKI is the only technology that extends trust beyond the enterprise with no a priori relationship between the trusted parties.
7
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.
8
Federal PKI Drivers Government Paperwork Elimination Act (GPEA) 1998
Requires Agencies to accept transactions, and maintain records electronically, when practicable
Electronic Signatures in Global and National Commerce Act (E-Sign) 2000An electronic signatures can not be denied legal status.
E-Government Act of 2002Achieve 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
9
E-Authentication OMB M-04-04
PKI level 3 & 4
AnonymousAccess level 1
Web Pages Time Card
User IDPassword
level 2
Patient DataAu
then
tica
tio
n M
ech
anis
m
Business Processes
Potential Impact of Authentication Errors
1 2 3 4
Inconvenience, distress, reputation Low Mod Mod High
Financial loss or agency liability Low Mod 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
E-Authentication Risk Assessment: http://www.cio.gov/eauthentication/documents/eraguide.pdf
10
Mandates new Federal ID Badge that is: 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
PIV-1: Identity proofing process October 2005 PIV-2: Smartcard ID Badge October 2006
Homeland Security Presidential Directive 12Policy for a Common Id Standard for Federal Employees and Contractors
11
FIPS 201 PIV Process
AuthorizeLocal sponsor fills out applicant’s badge request form, which is then approved by an Authorizing Official and forwarded to the Registration Authority.
RegisterRegistration Authority checks applicant’s identity documents; obtains applicant’s photograph, fingerprints and other background check data. Background check must be completed before badge issuance.
Each step must be performed independently by different people.Entire process and support systems must be accredited.
IssueIssuing Authority verifies applicant against registrationdata. Then creates and issues badge.
UseBadge accepted / electronically validated by all Agencies.PIN / biometrics used for stronger physical authentication.PKI certificates used for logical authentication to IT systems.
PIV-1Oct 05
PIV-2Oct 06
Badge loaded with applicant’s biometrics (fingerprints and photograph), PIN and PKI certificate information.
12
Tutorial
13
Foundations of PKI
14
Cryptography
Science of secret (hidden) writing kryptos – hidden graphen –to write
Encrypt / encipher Convert plaintext into ciphertext
Decrypt / decipher Convert ciphertext into plaintext
15
Early Examples of Cryptography
Shift Algorithm3 characters
Ciphertext: HW WX EUXWH
Plaintext: ET TU BRUTE
Julius Caesar (49 BC) substitution cipher
Spartan Scytale – fifth century BC
16
Symmetric Key Cryptography
Dear Bob:
I am leaving you.Goodbye forever.
Alice
011100111001001110011100111001001110000111111
ciphertext
encrypt decrypt
Dear Bob:
I am leaving you.Goodbye forever.
Alice
Alice Bob
Computationally fast Data Encryption Standard (DES)
Block Cipher, 56 bit key Triple DES 112 bit key
Advanced Encryption Standard (AES) Rijndael Algorithm Belgian cryptographers, Joan Daemen and Vincent Rijmen. 128, 192, 256 bit keys
Same key used to encrypt and decrypt
17
Symmetric Encryption Issues
Key (shared secret) vulnerable to discovery
Need to share a unique secret key with each party that you wish to securely communicate N * (N – 1) Problem Key management becomes unmanageable
18
Asymmetric Key Cryptography
011100111001001110011100111001001110000111111
decrypt encryptBob:
Leave me alone! Carol
Bob:
Leave me alone!
Carol
011100111001001110011100111001001110000111111
decryptencrypt
Carol’sPublic Key
Carol’sPrivate Key
Dear Carol:Alice is gone. Now we can be together
Love, Bob
Two mathematically related keys Unable to derive one from the other Based upon hard problem
RSA - Integer Factorization (large primes) Diffie-Hellman - Discrete Logarithms ECES - Elliptic Curve Discrete Logarithm
Public Key Cryptography One public key published for all to see Other is private key kept secret by owner
Dear Carol:
Alice is gone. Now we can be together
Love, Bob
Bob
Carol
Works both ways Can encrypt with either key – decrypt with the other
19
Asymmetric Advantages
No shared secret key Public key is public
Can be freely distributed or published Key management is much easier
Private key known ONLY to owner Less vulnerable, easier to keep secret
Supports Non-repudiation Encrypt with sender’s private key (only known by
sender) Sender can not deny sending message Basis for digital signatures
20
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.
21
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
Dear Mr. Bob:
We have asked theCourt to issue a restraining order against you to stayaway from Carol.
Sincerely,
Sue YewDewey, Cheatam & Howe, Law Firm
encrypt
Sue’sPrivate Key
01010111100001101011011110101111010111
DigitalSignature
0F47CEFFAE0317DBAA567C29
HashValue
HashFunction
Dear Mr. Bob:
We have asked theCourt to issue a restraining order against you to stayaway from Carol.
Sincerely,
Sue YewDewey, Cheatam & Howe, Law Firm
Sue
22
Validating a Digital Signature
Dear Mr. Bob:
We have asked theCourt to issue a restraining order against you to stayaway from Carol.
Sincerely,
Sue YewDewey, Cheatam & Howe, Law Firm
01010111100001101011011110101111010111
Sue’sPublic Key
0F47CEFFAE0317DBAA567C29
1. Re-compute the hash value2. Obtain the author’s public key
decrypt0F47CEFFAE0317DBAA567C29
3. Decrypt the original hash4. Compare hash values – if match signature is valid
Hash proves document unchanged integrity
Public key proves authorship non-repudiation
23
Asymmetric Issues
More computationally intensive 100x symmetric encryption
Generally not used to encrypt data Encrypt symmetric key (S/MIME) SSL session key
24
SMIME Encryption
Dear Carol:
I am still hoping when I get out of prison we can be together.
Love, Bob
encrypt
Carol'sPublic Key
encrypt011100111011001110010011100001
A032F17634E57BC43356743212b9c98FA29173425633A22201807732ECF13344567520ABCE4567CD
decrypt
Carol'sPrivate Key
decrypt
Dear Carol:
I am still hoping when I get out of prison we can be together.
Love, Bob
Bob Carol
Encrypted email uses the recipient's public key
25
Source of Public Key
Keys can be published anywhere Attached as a signature to e-mail
Pretty Good Privacy (PGP)
-----BEGIN PGP SIGNATURE-----Version: PGP 7.0.4
iQCVAwUBOx6SgoFNSxzKNZKFAQGK+gP6AnCVghZqbL3+rM5JMSqoC5OEYIkbvYZN92CL+YSCj/EkdZnjxFmU9+wGsWiCwxvs/TzSX6SZxlpG1bHFKf0OPu7+JEfJ7J5zcPCSqbFXiXzmukMl5KNx0p0veIDW4DmwleDpkmhT05qnCheweoNyvTSzfA1TGeLlmpjBi6zUjiY==Xq10-----END PGP SIGNATURE-----
26
But…
How do you know for sure who is the owner of a public key?
27
Public Key Infrastructure
Public Key Infrastructure (PKI) provides themeans 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!
28
X509.V3 Digital Certificate
Issued by a TRUSTED third party Certificate Authority (CA)
Creates and digitally signs Certificates Issues Certificate Revocation Lists (CRLs) or
Online Certificate Status Protocol (OCSP) Identity Proofing done by Local Registration Authority
(LRA)
29
PKI Users
Subscribers Entity who obtains certificates from a CA
Person, device, application, etc. Owns private key associated with public key in
certificate Non-repudiation requires only subscriber has access to
private key CA may escrow private key used for encrypted email Owner must protect private key
Password Safer with hardware token / smart card
Relying Party Entity who receives digital certificate Trusts CA who attests to certificate holder’s identity
30
How Certificates are used
Relying Party A
Relying Party Bencrypts messageto Subscriber
010111102101
Subscriber signsmessage to A
Get Subscriber'sCertificate
Directory
Get CRL to ValidateCertificate
Private key
Certificate
31
SSL Server Authentication
WWW
1. Client sends https request to server
2. Server sends its certificate to the client
3. Client decides if certificate (and issuing CA) is trustworthy4. Client validates certificate
5. Client sends to server session key - encrypted with server’s public key 6. Server decrypts session key with its private key
7. Client – Server transactions are now encrypted with session key
1
2Trust Issuing CA?
3
ValidateCertificate
CRL
4
5 6
7
32
Ever See this?
What do you do?
33
Trusted Third Party
PKI is built upon the concept of the trusted third party (i.e., CA)
But, who are you going to trust?
34
Who do you Trust?
Everyone trusts their own CA (trust anchor) Trust all certificates issued by their CA
CA
George Martha Clark
Single CA model does not scale well Difficult to manage across large or diverse
user communities
35
Hierarchical PKI
CAs have superior-subordinate relationships Higher level CAs issue certificates to subordinate CAs Subordinate CA issues certificate to subscriber
Forms a certification path (aka certificate chain) Chain of certificates from subscriber to root CA Root CA is top-level, self-signed (i.e., certified) CA
36
Certificate Chain
Root CARoot CA
Certificate Info
Root Signature
Sub CARoot Signature
Subordinate CA
Certificate Info
Root CA's Private Key
Root CA's Private Key
Subordinate CA's Private Key
SubCA's Signature
Subscriber
Certificate Info
Subscriber's Signature
Text
DocumentSubscriber's Private Key
Self Signed
37
Relying Party Certification Path
Green CA
Yellow
Gold
Mark
Blue
Red
Phyllis
A relying party builds a certificate path from the other subscriber to the relying party’s trust anchor
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
Green CA is Mark's trust anchor,therefore Mark trust's Phyllis's cert
38
What about other CAs?
How do you know if you can trust the CA?
Then, how much do you trust them?
39
Trust Lists
Commercial CAs often come pre-loadedWhy and how much do you trust a CA?
40
PKI Policies
Certificate Policy (CP) High level document Describes security policy for operating the CA Defines roles and responsibilities
How CA will be managed How registration will be performed (i.e., identity proofing
requirements) How subscribers use and handle their certificates and keys
Certification Practices Statement (CPS) 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 How much you should trust the CA’s certificates
PKI CP
CPS
PKI CP
CPS
41
However….
Users generally don’t examine policies
Most users just click YES
to trust CA
for expediency
42
Cross-Certified PKIs Peer-to-peer trust relationship
Between CAs or hierarchical PKI root CAs CAs review polices and issue certificates to each
other Advantages
CAs are organizationally independent Have independent policies
CA compromise does not effect others
Disadvantages Can form a MESH PKI CA needs to maintain multiple relationships
with other CAs Hard to build certification path
Multiple possible paths Loops and dead ends
Green CA Blue CA
Gold CA Red CA
Mark Phyllis
43
Bridge PKI Architecture
Bridge is trust arbitrator Only cross-certifies with other
CAs Relationships still peer-to-peer
Bridge is NOT a root CA Certification path construction is
much easier Bridge does all policy
management Less work for the CAs Maintains list of revoked CAs
(CARL)
Green CA Blue CA
Gold CA Red CA
Mark Phyllis
BridgeCA
44
Federal Bridge Certificate Authority
NFCPKI
HigherEd
BCA
NASAPKI
DOD PKI
Illinois PKI
University PKI
CANADA PKI
HospitalPKI
HealthCareBCA
All trust relationships handled by bridge CA
45
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
46
HHS PKI Program
47
Project Goals
PKI
Maintain and operate a public key infrastructure (PKI) to issue digital certificates to HHS entities (e.g., staff, applications, devices).
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.
48
Subscriber follows URL to web page and enters their pass phrase
Pass phrase
SSL
Certificate Issuance System
Edith EntityHHS/NIH/CITBldg 66, Room 99(301) 495-7734eenity@nih.gov
Edith Entity
Edith EntityHHS/NIH/CITBldg 66, Room 99(301) 495-7734eenity@nih.gov
Edith EntitySubscriber prints (bar-coded) registration form
Email sent to subscriberSubscriber
data
Validated subscriber is redirected to CA along with subscriber’s data
AD record is downloaded
DirectoryRecord
AD
Subscriber’s data stored in RA database Subscriberdata
RA App
Subscriber selects pass phrasePass phrase
Subscriber goes to registration web site enters MS credentials
LoginSSL
LRA scans form, validates informationand approves subscriber
Approval
Data
SSL
Subscriber takes form to LRA.Border
Directory
Certificates downloaded to subscriber’s browser and posted into Border Directory (and subsequently imported into AD)
49
Certificate Validation Service
PKE
1. Application receives certificate
1
2. PKI-enabled applications calls CAM
2
OTHERPKI
d. Other CAs trusted through FBCA
3d
3a
HHSPKI
3. CAM validates certificate with:a. HHS CA (DST)
b. Other ACES CAs
3b
TrustedPKI
c. Other CAs directly trusted by HHS
3c
4. CAM logs validation to meet GPEA/NARA electronic records requirements
4
50
Putting it all together
SSL
Subscriber
CRLs
Relying Party A
EncryptedEmail
CertificateStatus
FBCA
Relying Party B
Digitally Signed Document
Archive
CertificateRecords
Signature Validation records
Subscriber
Cross-Certification
TLS Reg Staff RegBorder
Directory Certificate Status Information to other PKIs
Signed Documents
From other PKIs
Other PKI
CertificateStatus
+
+
51
Obtaining your HHS Certificate
52
Request Your Certificates
53
Identify Yourself
54
ActiveX Requirements
55
Review Steps
56
Identify your Employer
57
Verify Your Information
If incorrect, see your local system administrator
58
Pick One-Time Pass phrase
You will need this pass phrase to get your certificates in the last step
59
Download/Print Request Form
Click here to download form
60
PKI Certificate Request Form
Notary information is ONLY collected if can not appear in-person before LRA
Second form of ID is needed ONLY if Federal badge doesn’t have unique ID number
Photocopy Governmentpicture ID onto form
Don’t sign / date until you are before an LRA
Contractors need customer’s signature(e.g., PM, AO)
61
Take Completed Form to LRA
62
Enabling ActiveX
Tools -> Internet Options -> Security
63
Email Notification
Click on this URL to obtain your certificates
64
Enters Pass Phrase
If you forgot your passphrase, you will need to repeat the form creation and LRA process
Enter pass phrase
65
Install Active-X Module
Click YES to install. Some “locked down”desktops may (currently) require system admin. support
66
Review & Accept Subscriber Agreement
Check this box
67
Download Instructions
Click link to download PDF
Click box
Then click next
68
Begin Retrieval Process
Click
69
Microsoft Warning
Click YES
70
Change Security Level
You MUST click here to set security level to HIGH
in order to password protect your private key
71
Set Security Level to High
Check HIGHThen click Next
72
Set Password for Private Key
You must REMEMBER this password. It can not be reset by an administrator.
73
Click OK to Save Setting
After setting security level to HIGH
You may now click OK
74
Processing...
75
Review Your Certificates
76
Download Encryption Certificate
77
Repeated Microsoft Warning
Click YES
78
Repeat Setting Security Level to High
79
Set Encryption Password
You may use the SAME password you entered for your signing Certificate
80
Certificate Download Complete
81
Configuring Outlook
Tools → Options
82
Tools → Options → Security → Settings…
Click Settings
Security tab
83
Specify Signing Certificate
Specify ANY name you like
ClickChoose
84
Select DST ACES Certificate
If more than one pick Certificate issued byDST ACES Federal Employee CA
85
Specify Encryption Certificate
ClickChoose
86
Publish to GAL
87
Enter Certificate Password
You will be prompted to enter your password each time you use your certificate
Do NOT Check
88
Using Your Certificates
89
Sending Signed/Encrypted Email
90
If using Microsoft Office Word to edit e-mail messages
Message Options
91
Security Settings
92
Send
NEVER
Enter PKI private key password to sign email
93
Receiving Secure Email
94
Click Ribbon for Details
Lock showsMessage was
encrypted
95
Add Buttons to toolbar
Uncheck to set to default
message editor
96
Configure Message Editor
Buttons automatically migrate to Word editor as well
97
Adobe 7.0
98
Create Adobe Signature
99
Position Adobe Signature
100
Select Certificate
101
Specify Reason for Signature
102
Private Key Password
NEVER
103
First Time – May not be Trusted
104
Enable Windows Trust
105
Validate Signature
Right Click
106
Add Trusted CA (Macintosh)
Right Click
107
Signing a Word Document
108
Signed Document
DoubleClick
109
Managing Your Certificates
110
Export (backup/move)
111
Pick First Certificate
112
Specify File and Password
This is a NEW password to protect the FILE!
Filename
Password
113
Enter Certificate Password
This is the OLD password used to protect your private key
114
Repeat for Second Certificate
115
Import Certificate
Filename andpasswordfrom export
Must enter aname. Useany name you like.
116
Set Security Level to High
Import/export is way to password protect private key if you failedto set security level when initially obtaining your certificates.
117
Create New Password
This is the password to protect your private key.
118
Repeat for Second Certificate
119
Internet Explorer
120
Tools → Internet Options → Content…
Content Tab
ClickCertificates….
121
Can Export/Import/Delete
122
LRA Subscriber Registration
123
HHS PKI LRA Home Page
124
Certificate Authentication
125
First Time Download
126
LRA Management Page
127
Collect Registration Data
128
Approve Request
129
Registration Complete
130
Questions
Answers: http://www.pki.hhs.govhttp://www.pki-page.org/http://www.rsasecurity.com/rsalabs/faq/http://csrc.nist.gov/pki/mls@nih.gov
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