Cryptography

1
Cryptography
2
Introduction

• Encryption
• The art (or science) of putting messages into a
  code, and the study of those coding techniques.
• Decryption
• The means by which to bring out the meaning from
  a coded message.

3
Simple Techniques

• Original text testing
• Reversing text
• gnitset
• Shifting text
• uftujoh
• Flipping text
• ettsnig
• Caeser cipher
• Multi-shift (this one is by 2)
• vguvkpi
• Examples

4
Cryptography

• Public Key Encryption
• You create a private key/public key pair
• If a message is encrypted with your private key,
  only your public key will decrypt it
• Publish your public key on web sites or send it
  to people via e-mail
• Uses
• If you want to send a private message to another
  person, encrypt it with their public key (only
  they can decrypt it with their private key)
• Digital Signatures
• Encrypt with your private key first and then
  their public key
• PGP (Pretty Good Privacy)
• One version of this technology
• Example