Public Key Cryptography

PKI (Public Key Infrastructure) 

  • CA (Certificate Authority) binds public key with identity. = TTP Trusted Third 
  • Party. E.g. Symantec, Comodo, GoDaddy
  • OSCP Responder
  • RA (Registration Authority) = subordinate CA in Microsoft PKI. 
  • VA (Validation Authority) 
  • Central Directory to store index keys
  • Certificate Management System
  • Certificate Policy
Method of certification

1. CA

2. Web of Trust. E.g. PGP (Pretty Good Privacy) and GnuPG
3. Simple Public Key Infrastructure (SPKI). Authorization loop : verifier = issuers 

Open Source implementation of CA

  • OpenSSL is the simplest CA and tool to build PKI enabled apps. C. Part of all major Linux distributions, 
  • EJBCA is a full featured, Enterprise grade, CA implementation. Java. 
  • OpenCA is a full featured CA implementation 
  • XCA is a graphical interface, and database. 
  • (Discontinued) TinyCA was a graphical interface for OpenSSL.
  • XiPKI CA and OCSP responder. With SHA3 support, OSGi-based Java.
  • IoT_pki is a simple PKI. Python cryptography library
  • DogTag
  • gnoMint
  • EasyRSA, OpenVPN's command line CA utilities using OpenSSL.
  • r509
  • Boulder is an automated server that uses the Automated Certificate Management Environment (ACME) protocol.
  • Windows Server : Active Directory Certificate Services.
Free digital certificate for public by CA

  • CAcert
  • Let's Encrypt.


Public Key Cryptography Standards :
Cryptographic Message Syntax : and RFC 2315, RFC 2360, RFC 3369


1. Introduction to cryptography and network security

2. Cryptography theory and practice

3. Field Arithmetic 

4. Problems in the Theory of Modular Forms


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