The Implications of EncryptionThe Implications of Encryption

Curtis A. Carver Jr. and John M.D. HillCurtis A. Carver Jr. and John M.D. HillDepartment of Electrical Engineering and Computer ScienceDepartment of Electrical Engineering and Computer Science

United States Military AcademyUnited States Military Academy

October 22, 2003October 22, 2003 Federal Information Assurance ConferenceFederal Information Assurance Conference 22

AgendaAgendaUnderlying Technologies

– Symmetric Encryption– Asymmetric Encryption– Digital Signatures– Digital Certificate– Hash Functions– Public Key

Infrastructure– PGP Example

Underlying TechnologiesUnderlying Technologies–– Symmetric EncryptionSymmetric Encryption–– Asymmetric EncryptionAsymmetric Encryption–– Digital SignaturesDigital Signatures–– Digital CertificateDigital Certificate–– Hash FunctionsHash Functions–– Public Key Public Key

InfrastructureInfrastructure–– PGP Example

Implications– It’s everywhere, it’s

everywhere!EncryptionComputing Devices

– Moore’s Law, Quantum Computing, & Virtual Bears, Oh My!

– End of the Code Breakers?

– Let’s Get Ready to Rumble! Privacy vs. Authentication

ImplicationsImplications–– It’s everywhere, it’s It’s everywhere, it’s

everywhere!everywhere!EncryptionEncryptionComputing DevicesComputing Devices

–– Moore’s Law, Quantum Moore’s Law, Quantum Computing, & Virtual Computing, & Virtual Bears, Oh My! Bears, Oh My!

–– End of the Code End of the Code Breakers?Breakers?

–– Let’s Get Ready to

PGP Example

Let’s Get Ready to Rumble! Privacy vs. Rumble! Privacy vs. AuthenticationAuthentication

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Encryption is EverywhereEncryption is Everywhere

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Symmetric EncryptionSymmetric Encryption

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Symmetric EncryptionSymmetric Encryption

Fast encryption and decryption Fast encryption and decryption but problematic key distributionbut problematic key distribution

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Asymmetric EncryptionAsymmetric Encryption

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Public Key Cryptography is…

Certificates containing key pairs. One half of a key pair is used to encrypt, the other half is used to decrypt.

EncryptionEncryption

Recipient’sPublic

Key

Recipient’sPrivate

Key

DecryptionDecryption

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Asymmetric Encryption Asymmetric Encryption Slow performance Slow performance (compared to symmetric encryption) (compared to symmetric encryption) but key distribution easier than symmetricbut key distribution easier than symmetric

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Digital SignaturesDigital Signatures

Digital signatures not only prove who sent a Digital signatures not only prove who sent a message, they are attest that the message message, they are attest that the message was not changed.was not changed.

However, they are slow and double the However, they are slow and double the message size.message size.

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Digital SignaturesDigital Signatures

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Hash FunctionsHash FunctionsVariable Length

Message

Hash Function

Fixed Length Digest

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Digital Signatures with HashesDigital Signatures with Hashes

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Digital CertificatesDigital CertificatesIs Is Alice’sAlice’s public key really public key really Alice’sAlice’s public key or is it public key or is it really really evil Sarahevil Sarah pretending to be pretending to be AliceAlice (who is (who is locked up in the closet)? locked up in the closet)?

Digital Certificates have three components:Digital Certificates have three components:A public keyA public keyCertificate informationCertificate informationOne or more digital signaturesOne or more digital signatures

X.509 is a common format for digital certificates.X.509 is a common format for digital certificates.

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Public Key InfrastructurePublic Key Infrastructure

–– Used to manage digital certificates by issuing, Used to manage digital certificates by issuing, trusting and revoking certificates.trusting and revoking certificates.

–– Two components:Two components:Certification AuthorityCertification Authority: creates certificates and signs : creates certificates and signs them. them. Registration AuthorityRegistration Authority: the people, processes, and : the people, processes, and tools used to support registration of users. tools used to support registration of users.

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Pretty Good Privacy (PGP)Pretty Good Privacy (PGP)“It's personal. It's private. And it's no one's business but yours.”

Created by Phil Created by Phil Zimmermann in 1991.Zimmermann in 1991.Freeware and commercial Freeware and commercial products.products.The focal point for a The focal point for a national debate on strong national debate on strong encryption export control encryption export control during the 1990s. during the 1990s. The debate ended in 1999 The debate ended in 1999 with privacy winning out. with privacy winning out.

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PGP OperationPGP Operation

Session KeyGenerationRandom NumberGenerator

Compression

Huffman

AsymmetricEncryptionRSA

SymmetricEncryptionIDEA - 128CAST - 1283DES - 112

M Comp(M)

SK

SK

File containing:

PKB(SK)

and

SK(Comp(M))

and

SKA(Hash(M))

PKB(SK)

SK(Comp(M))

PKB

AsymmetricEncryptionRSA

SKA

SKA(Hash(M))

Hash

MD5

PKB

Hash(M)

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PGP Operation PGP Operation

M Compression

ZIP, ZLIB, BZip2

Hash

MD5, SHA-1

Session KeyGeneration

Random NumberGeneration

PKB

AsymmetricEncryption

RSA, Elgamal

SymmetricEncryption3DES, AES,

Blowfish, Twofish

File contains

PKB(SK)

and

SK(Comp(M))

and

SKA(Hash(M))

SK

SK PKB(SK)

SK(Comp(M)Comp(M)

SKA(Hash(M))

Digital SignatureRSA, DSA

Hash (M)

SKA

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How Good is PGP?How Good is PGP?"If all the personal computers "If all the personal computers in the world in the world -- 260 million 260 million --were put to work on a single were put to work on a single PGPPGP--encrypted message, it encrypted message, it would still take an estimated would still take an estimated 12 million times the age of 12 million times the age of the universethe universe, on average, to , on average, to break a single message.” break a single message.”

William Crowell, William Crowell, Deputy Director, NSA, Deputy Director, NSA, March 20, 1997. March 20, 1997.

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PGP UniversalPGP Universal

Released by PGP Corporation Released by PGP Corporation ((www.pgp.comwww.pgp.com))Shifts email encryption from the desktop to Shifts email encryption from the desktop to the network so that it becomes a transparent the network so that it becomes a transparent service. service. Provides mechanisms to handle internal and Provides mechanisms to handle internal and external traffic as well as recipients without external traffic as well as recipients without a email security solution.a email security solution.

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PGP UniversalPGP Universal

No requirement for user to distribute public No requirement for user to distribute public keys.keys.No requirement for user to decide when to No requirement for user to decide when to implement security policy. implement security policy. Ability to project security policy to secure Ability to project security policy to secure electronic boundaries. electronic boundaries.

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PGP UniversalPGP Universal

ImplicationsImplications

Encryption is no longer too hard or Encryption is no longer too hard or too slow for routine operations.too slow for routine operations.

It will spread everywhere.It will spread everywhere.

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ImplicationsImplications

The plethora of The plethora of computing devices and computing devices and their interconnectivity their interconnectivity pose new risks.pose new risks.

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ImplicationsImplications

Life gets more complicated while we figure Life gets more complicated while we figure how to live with ubiquitous encryption.how to live with ubiquitous encryption.–– Bad and good folks get more privacy.Bad and good folks get more privacy.–– Bad and good folks get more authentication.Bad and good folks get more authentication.–– Authorization gets harder to check.Authorization gets harder to check.–– We continue to use a variety of techniques to We continue to use a variety of techniques to

keep bad guys on the run. keep bad guys on the run.

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Implications Implications (Information Technology)(Information Technology)

–– Moore’s law remains Moore’s law remains true but is not a factor.true but is not a factor.

–– Quantum computing Quantum computing may change everything may change everything but it is unlikely. There but it is unlikely. There are physical limits that are physical limits that smart folks like Einstein smart folks like Einstein think we cannot think we cannot surpass and some surpass and some problems remain problems remain difficult to solve.difficult to solve.

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ImplicationsImplications

Growing social and legislative pressure to Growing social and legislative pressure to protect privacy of personally identifiable or protect privacy of personally identifiable or company confidential information while it is in company confidential information while it is in storage, being processed, or in transit. storage, being processed, or in transit.

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ImplicationsImplications

Privacy remains an issue not because Privacy remains an issue not because everyone can read our mail, but because everyone can read our mail, but because everyone can identify us. everyone can identify us.

Will the demands for authentication (national Will the demands for authentication (national ID card) destroy privacy, ensure safe ID card) destroy privacy, ensure safe computing, both, neither or none of the computing, both, neither or none of the above? above?

The Implications of EncryptionThe Implications of Encryption

Curtis A. Carver Jr. and John M.D. HillCurtis A. Carver Jr. and John M.D. HillDepartment of Electrical Engineering and Computer ScienceDepartment of Electrical Engineering and Computer Science

United States Military AcademyUnited States Military Academy