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Chapter 10 Encryption: A Matter of Trust

Chapter 10 Encryption: A Matter of Trust. Encryption: Objectives. OBJECTIVES. What is Encryption? Basic Cryptographic Algorithm Digital Signatures Major Attacks on Cryptosystems Digital Certificates Key Management Internet Security Protocols & Standards Government Regulations.

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Chapter 10 Encryption: A Matter of Trust

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  1. Chapter 10Encryption: A Matter of Trust

  2. Encryption: Objectives OBJECTIVES • What is Encryption? • Basic Cryptographic Algorithm • Digital Signatures • Major Attacks on Cryptosystems • Digital Certificates • Key Management • Internet Security Protocols & Standards • Government Regulations

  3. Encryption: What is Encryption? WHAT IS ENCRYPTION? • Based on use of mathematical procedures to scramble data to make it extremely difficult to recover the original message • Converts the data into an encoded message using a key for decoding the message

  4. Encryption: What is Encryption? WHAT DOES ENCRYPTION SATISFY? • Authentication • Integrity • Non-repudiation • Privacy

  5. Encryption: Basic Cryptographic Algorithm BASIC CRYPTOGRAPHIC ALGORITHM • Secret Key • The sender and recipient possess the same single key • Public Key • One public anyone can know to encrypt • One private only the owner knows to decrypt • Provide message confidentiality • Prove authenticity of the message of originator

  6. Encryption: Basic Cryptographic Algorithm COMMONLY USED CRYPTOSYSTEMS • RSA Algorithm • Most commonly used but vulnerable • Data Encryption Standards (DES) • Turns a message into a mess of unintelligible characters • 3DES • RC4 • International Data Encryption Algorithm (IDEA)

  7. Encryption: Digital Signatures DIGITAL SIGNATURES • Transform the message signed so that anyone who reads it can be sure of the real sender • A block of data representing a private key • Serve the purpose of authentication

  8. Encryption: Major Attacks on Cryptosystems MAJOR ATTACKS ON CRYPTOSYSTEMS • Chosen-plaintext Attack • Known-plaintext Attack • Ciphertext-only Attack • Third-party Attack

  9. Encryption: Digital Certificates DIGITAL CERTIFICATES • An electronic document issued by a certificate authority (CA) to establish a merchant’s identity by verifying its name and public key • Includes holder’s name, name of CA, public key for cryptographic use, duration of certificate, the certificate’s class & ID

  10. Encryption: Digital Certificates CLASSES OF CERTIFICATES • Class 1 • Contains minimum checks on user’s background • Simplest & quickest • Class 2 • Checks for information e.g. names, SSN, date of birth • Requires proof of physical address, etc.

  11. Encryption: Digital Certificates CLASSES OF CERTIFICATES (Cont’d) • Class 3 • You need to prove exactly who you are & that you are responsible • Strongest • Class 4 • Checks on things like user’s position in an organization in addition to class 3 requirements

  12. Encryption: Key Management KEY MANAGEMENT • Key Generation & Registration • Key Distribution • Key Backup / Recovery • Key Revocation & Destruction

  13. Encryption: Key Management THIRD PARTY SERVICES • Public Key Infrastructure • Certification Authority • Registration Authority • Directory Services • Notary Services • Arbitration Services

  14. Encryption: Internet Security Protocols & Standards INTERNET SECURITY PROTOCOLS & STANDARDS • Web Application • Secure Socket Layer (SSL) • Secure Hypertext Transfer Protocol (S-HTTP) • E-Commerce • Secure Electronic Transaction (SET) • E-Mail • PGP • S/MIME

  15. Encryption: Internet Security Protocols & Standards SSL • Operates between application & transport layers • Most widely used standard for online data encryption • Provide services: • Server authentication • Client authentication • Encrypted SSL connection

  16. Encryption: Internet Security Protocols & Standards S-HTTP • Secures web transactions merely • Provides transaction confidentiality, integrity & non-repudiation of origin • Able to integrate with HTTP applications • Mainly used for intranet communications • Does not require digital certificates / public keys

  17. Encryption: Internet Security Protocols & Standards SET • One protocol used for handling funds transferred from credit card issuers to a merchant’s bank account • Provides confidentiality, authentication & integrity of payment card transmissions • Requires customers to have digital certificate & digital wallet

  18. Encryption: Internet Security Protocols & Standards PGP • Encrypts the data with one-time algorithm, then encrypts the key to the algorithm using public-key cryptography • Supports public-key encryption, symmetric-key encryption & digital signatures • Supports other standards, e.g. SSL

  19. Encryption: Internet Security Protocols & Standards S/MIME • Provides security for different data types & attachments to e-mails • Two key attributes: • Digital signature • Digital envelope • Performs authentication using x.509 digital certificates

  20. Encryption: Government Regulations GOVERNMENT REGULATIONS • National Security Agency (NSA) • National Computer Security Center (NCSC) • National Institute of Standards & Technology (NIST) • Office of Defense Trade Controls (DTC)

  21. Chapter 10Encryption: A Matter of Trust

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