Introduction to PGP for E-mail

Peter E. Murray, OhioLINK

Based in part on OpenPGP/GnuPG Encryption, Tanner Lovelace, Triangle Linux Users Group

Why do you need cryptography?

• Privacy: Keep communications secret
• Integrity: Keep communications secure
• Authentication: Know who you’re communicating with
• Nonrepudiation: A sender shouldn’t be able to deny that they sent a message

Cryptography Background

Two main types of cryptography

• Symmetric
  • Same key encrypts/decrypts
  • DES, AES, IDEA
• Asymmetric
  • Different keys for encryption/decryption
  • Also called public key cryptography
  • RSA, Diffie-Hellman, ElGamal

Which is better?

• • Answer:
  • neither
• Symmetric encryption is much faster than asymmetric
• Asymmetric makes communicating with people you don’t know much easier