PKI Implementation - Introduction to Cryptography - Lecture Slides, Slides of Network security

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PKI Implementation

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PKI Implementation

• User names and PKI
• Trust
• Authorization
• Revocation
• Keys and PKI

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User names and PKI

• Certificate Authority assigns unique names
• CA also provides verification

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Trust

• PKI enables key management for

cryptography

• PKI relies on the trustworthiness of the CA
• Cryptography emphasizes trust for key

exchange

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Authorization

• Credentialing is another way to provide

authorization

• Credentialing enables time-based

authorization

• Credentialing could be cumbersome in

online validation of certificates

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Revocation

• CA revokes certificates based on:
  • User request (possibly lost key)
  • Failure to follow policies
  • Employee left the organization
• Users should be educated to check for revocation
• Revocation involves:
  • Reliability
  • Speed
• Revocation system should be dynamic

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Keys and PKI

• Key server could perform the role of PKI
• Key server has some disadvantages
• Key server must be available all the time for validation
• PKI, because of CRL and expiration, does not have to be available all the time
• Key server is centralized by its very nature
• PKI uses certificates used by CAs by other validation means

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Keys and PKI

• PKI provides non-repudiation
• The root key of CA need not be online for

authentication or verification

• PKI is more complex than a key server

system

• Key servers are well suited for small

systems

• PKI is well suited for large systems

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Keys and PKI

• Alice generates the public/private key and

shares the public key with the CA who validates Alice

• CA distributes the public key
• Keys should have a passive use time with

reference to expiration of key