Cryptography

Cryptography

1. Asymmetric

   • A pair of keys are used -> They are also known as Public key cryptography because there are a public key and a private key, 2 for each party.
   • Certificates
   • Diffie-Hellman
     • ECDH
   • RSA
   • DSA
     • ECDSA

2. Symmetric

   • These algorithms use 1 symmetric key both for encryption and decryption.  Are particularly suitable for large amount of data.
   • Block Algorithms
     • They split data in blocks of equal size, then process 1 block at time.
     • DES
       • 3DES (EEE or EDE)
     • IDEA
     • RC2
     • RC5
     • AES
     • Operation modes
       • These are applied in case the data dimension is different from the basic block dimension
       • data > basic block
         • ECB
         • CBC
         • IGE
         • CTS
           • This not uses padding and does not send more that than necessary
         • Padding
       • data < basic block
         • CFB
         • OFB
         • CTR
   • Stream Algorithms
     • Able to work on stream of data, 1 bit or byte at time.
     • RC4
     • SEAL
     • Key stream
       • pseudo-random key
       • one-time pad