Upload File

pki overview tim polk, nist [email protected]. background u secret key cryptography works, but key...

  • Home
  • Documents
  • PKI Overview Tim Polk, NIST [email protected]. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses
33
PKI Overview Tim Polk, NIST [email protected]

Post on 18-Dec-2015

218 views

Category:

Documents


0 download

Report

TRANSCRIPT

Page 1: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

PKI Overview

Tim Polk, NIST

[email protected]

Page 2: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Background

Secret key cryptography works, but key management is a nightmare

Public key cryptography uses two keys– one that is secret to the “owner”– one that is widely available

And all our problems were solved?– who’s key is this anyway?– who says so?

Page 3: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Public Key Infrastructure

Secure, reliable, and scalable method for distributing public keys for secrecy, correctness, and sender verification

“Binds” the owner to the public key using a digital certificate

Maintains and distributes status information for the life of that binding

Page 4: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Roles of PKI Components

CA is like the DMV and issues and revokes certificates

RA is the person that checks your identity Client have and use certificates Repository stores the certificate and status

information so clients don’t have to

Page 5: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

A Basic PKI

We can deploying these right now

CA

Clients

repository

Bob Alice

Page 6: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Growing A PKI

bigger PKIs can be constructed by connecting CAs

they issue certificates to remote CAs, binding the remote CA to it’s public key

clients can construct “chains” of linked bindings

Page 7: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Public Key Infrastructure

A “real” PKI has multiple CAs with clients CAs and repositories are the basic building

block

CA-3

Bob

repository

CA-2

CA-1

repository

Alice

Carol

Page 8: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

PKIs are simple...

as long as you have just one CA and one repository– theoretically, they are like lego blocks– in practice, they can be like a box of bicycle

parts on Christmas Eve the complexity is the result of

– unstable standards– non-interoperable products and applications

Page 9: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Standardization Activities

IETF (PKIX WG) ISO JTC1/SC6 directory work ANSI X9F and ISO TC68/SC 2/WG 8

Page 10: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

IETF Public Key Infrastructure Using X.509 (PKIX) WG

Formed in 1995 Five RFCs issued in ‘99, four more

approved in the last month– certificate and CRL formats– PKI transaction formats and protocols– Certificate Policy Statements– certificate and certificate status retrieval

mechanisms

Page 11: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Certificate and CRL Formats

Base profile is complete (RFC 2459)– based on X.509, but adds semantics to Internet-

specific fields and data Supporting documents are (nearly)

complete– KEA (RFC 2527) and ECDSA (I-D)– enhanced CRLs (I-D)– enhanced name semantics (I-D)

Page 12: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Transaction Formats and Protocols

Three major specifications– Certificate Request Message Format, or CRMF

(RFC 2511)– Certificate Management Protocol, or CMP

(RFC 2510) [references 2511]– Certificate Management Messages over CMS,

or CMC (I-D) [references 2511] Is there room for CMP and CMC?

Page 13: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Certificate and Certificate Status Retrieval

A wealth of choices– LDAP V2 schema– LDAP V2 profile– FTP and HTTP– OCSP

Page 14: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

New PKIX Work

Timestamp service protocol Data certification service protocol Attribute certificates

Page 15: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

ISO Directory Work

Three projects in the directory area were assigned to JTC1/SC6– X.509

» maintaining the public key certificate work

» new work in attribute certificates

– X.500 directory work– ASN.1 (X.680?)

Page 16: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

ANSI X9F

Provider of cryptographic standards Developing certificate and certificate

extension profiles for banking community– TC68 documents 15782-1 and 15782-3

Defining short certificates for bandwidth or storage impaired environments– smart cards, cell phones, etc.

Attribute certificate work (15782-2)

Page 17: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Standardization Summary

ISO, IETF and ANSI are making good progress

Most of the work is complementary, or at least well-aligned

There are still too many choices in some areas (transaction and retrieval protocols)

Parallel attribute certificate projects may result in divergent standards

Page 18: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Interoperability Testing

The new frontier– PKI interoperability– PKI component interoperability

Issues:– are certificates and CRLs well-formed?– can components request/revoke certificates?– can clients build/validate paths?

Page 19: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

NIST’s PKI Interoperability Testbed

Project Goals:– Creation of complex directory systems– Creation of heterogeneous PKIs– Determination of client functionality

Summary:– the state of the art is a homogeneous PKI with

a very small number of CAs and exactly one directory

Page 20: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

PKI Component Interoperability Testing

Three basic components– CAs: X.509 certificate and CRL generation– Clients: X.509 path validation– CAs, RAs, clients: transaction message formats

and protocols As protocols stabilize, interoperability

testing is the logical next step

Page 21: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Tools for Interoperability Testing

reference implementations– MISPC Reference Implementation from NIST

(X.509, CMP, and CRMF)– IBM (X.509, CMP, and CRMF)

Conformance tests– NIST (CMP, CRMF)

Page 22: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

PKI deployment

Many pilots ongoing or planned– “many will play, few will win!”

Why?– directory infrastructure– application vacuum– unreasonable expectations

Page 23: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Directories

Often the problem, instead of the solution!– X.500 directories– LDAP directories

Alternative solutions– alternative retrieval protocols– all-inclusive packaging

Page 24: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

X.500

the global X.500 directory is a myth– it would resolve most access problems– it would introduce new problems

» DIT management

– shadowing, replication and chaining» well specified

» not well tested (different implementations don’t actually interoperate!)

Page 25: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

LDAP

LDAP is ubiquitous, but: – resolves localized access problems– relies on referrals to scale

» performance bottleneck

» poor client support

– shadowing, replication and chaining» proprietary solutions, if they exist at all

» may be addressed in LDAP V3 extensions

Page 26: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Alternative Solutions

Why rely on directories at all?– FTP/HTTP/DNS retrieval

» we’ve already got these servers, and they work!

» requires a pointer in the certificate

– all-inclusive packaging (S/MIME)» just include the certificate(s) and CRL(s) in each

transaction and the client doesn’t have to search

» not a complete solution because you can’t always predict the path for the receiving client

Page 27: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

The Application Vacuum

PKI-aware products are limited– TLS and SSL (browsers), S/MIME

Why aren’t there more PKI-aware products?– chicken and egg problem (what PKI?)– not a straightforward upgrade (e.g., adding

digital signatures to insecure applications)– no standard API (rewrite for every product)

Page 28: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Unreasonable Expectations

PKI is a not going to solve all your problems– first and foremost, PKI is a key management

solution– overloading with additional semantics (e.g.,

roles and complex policies) is beyond the state of the art

Page 29: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Piloting for Success

choose an existing application with:– a close-knit community of users– security in place (esp. access control), but – a known key management problem

use a single repository for all information focus on the key management problem first attempt to leverage certificates for access

control second (if at all)

Page 30: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Current Market Players

PKI product providers– rudimentary assurance– high assurance

Service providers– certificate issuers– status information providers

Community of Interest Groups– ANX, Federal Government, financial

Page 31: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Community of InterestGroups Rule

they determine the winners and losers– communities of interest that use the PKI will

determine the features and protocols – if no communities emerge to use PKI, it will all

disappear they are emerging (ANX, US government,

SET, etc.) and PKI will appear in more applications

Page 32: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

Summary

The standards bodies have gotten their act together, but a few thorns remain

The state of the art PKI products– can support focused applications today

– can’t support a global infrastructure today

– aren’t interoperable, but will be “soon” Application and directory solutions are lagging,

but vendors will respond to communities of interest deploying PKIs

Page 33: PKI Overview Tim Polk, NIST wpolk@nist.gov. Background u Secret key cryptography works, but key management is a nightmare u Public key cryptography uses

For More Information

http://csrc.nist.gov/pki [email protected]


Key Exchange With Public Key Cryptography

Chapter 9 Public Key Cryptography and RSA. Private-Key Cryptography traditional private/secret/single key cryptography uses one key shared by both sender

Pubic-Key Cryptography

1 Lecture 2: Introduction to Cryptography Outline uses of cryptography secret key cryptography public key cryptography message digests

Part 1 Cryptography 1 Chapter 4: Public Key Cryptography Knapsack RSA Diffie-Hellman key Elliptic Curve Cryptography Public key crypto application

Public-Key Cryptography

Bronson Jastrow. Outline What is cryptography? Symmetric Key Cryptography Public Key Cryptography How Public Key Cryptography Works Authenticating

Chapter 9 – Public Key Cryptography and RSA Private-Key Cryptography traditional private/secret/single key cryptography uses one key shared by both

Private-Key Cryptography

Public Key Cryptography

Cryptography - cs.drexel.edugreenie/cs645/CS645-13-05.pdfCryptography • Symmetric key cryptography (secret key crypto): sender and receiver keys identical • Asymmetric key cryptography

CRYPTOGRAPHY Gayathri V.R. Kunapuli. OUTLINE History of Cryptography Need for cryptography Private Key Cryptosystems Public Key Cryptosystems Comparison

Cryptography - Key Agreement and Key Transport Using Elliptic Curve Cryptography

Java*Cryptography - Cogent Logic · Java*Cryptography Symmetric*Key*Cryptography • Cryptography. Cryptography

Public-Key Cryptography - Stanford University · Public-Key Cryptography Public-Key Cryptography Eric Roberts CS 54N November 7, 2016 Public-Key Encryption • In 1999, shortly before

Methods of Public-Key Cryptography Emilie Wheeler · cryptography can be divided into two large branches: Private-Key Cryptog-raphy and Public-Key Cryptography. Private-key cryptography,

symmetric key cryptography

Chapter 10 Asymmetric-Key · PDF fileObjectives Present asymmetric-key cryptography. Distinguish between symmetric-key cryptography and asymmetric-key cryptography. Introduce trapdoor

Secret Key Cryptography

Public-Key Cryptography

Public Key Cryptography and RSAblk/cryptography/ch09-publicKey... · 2006-06-28 · Public Key Cryptography and RSA • Major topics – Principles of public key cryptosystems –

Beginning Cryptography With Java - Symmetric Key Cryptography

Cryptography - Dalhousie Universitytt/ECMM6010/6010_crypto.pdf · – Diffie-Hellman key exchange – Public-key cryptography RSA elliptic curve cryptography 12 23 Key generation

Cryptography or Smalltalkers 2 Public Key Cryptography

[MS-PKCA]: Public Key Cryptography for Initial ...... · Public Key Cryptography for Initial Authentication (PKINIT) ... The Public Key Cryptography for Initial ... for Initial Authentication

Symmetric-Key Cryptography · cryptography does not eliminate the need for symmetric-key cryptography. Need for Both . The main idea behind asymmetric-key cryptography is the concept

Public Key Cryptography - ict.ac.cnbioinfo.ict.ac.cn/~dbu/AlgorithmCourses/Lectures/Lec6-Knapsack... · Public Key Cryptography • Motivations – In symmetric key cryptography,

Part 1 Cryptography 1 Chapter 4: Public Key Cryptography RSA Diffie-Hellman key Elliptic Curve Cryptography Public key crypto application