Networking / Beginners

Keyspace

The keyspace is related to the key used for encryption and decryption. The keyspace refers to the range of possible values that can be used in the key. The wider the range of the keyspace, the more difficult it can be to break or compromise the encryption.

Keystream

A keystream is a stream of random or pseudo-random data that is combined with the plain-text to produce cipher-text. Different mathematical or logic operations can be performed on the keystream in combination with the plain-text to generate the ciphertext. The keystream is not necessarily related to the key or the safeguarded information in any way.

The following logic operations can be performed on the keystream and plain-text (among others):

  • Conjunction (AND)
  • Disjunction (OR)
  • Negation (NOT)
  • Not both (NAND)
  • Neither Nor (NOR)
  • Exclusive OR (XOR)

Note Pseudo-random numbers are a series of numbers that are similar to random numbers but cannot be defined as being completely random, because they are generated from a relatively small set of initial values. Their scope is limited or finite.

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In this tutorial:

  1. Securing Wireless Networks
  2. Security Background
  3. Security Services
  4. Cryptographic Concepts and Terms
  5. Encryption and Decryption
  6. Keyspace
  7. Exclusive OR (XOR)
  8. Algorithm
  9. Asymmetric Encryption Algorithms
  10. Public-Private Key Cryptography
  11. Cipher
  12. Concealment Ciphers vs. Running Key Ciphers
  13. Stream Ciphers vs. Block Ciphers
  14. Cipher Examples
  15. Cipher Implementations
  16. Wi-Fi Protected Access
  17. TKIP/WPA
  18. Wi-Fi Protected Access 2 (WPA2)
  19. CCMP/AES
  20. Hash Functions
  21. EAP
  22. EAP Entities
  23. EAP Grammar
  24. EAP Types
  25. EAP-TTLS
  26. EAP-PSK
  27. EAP-SIM
  28. EAP-AKA
  29. IEEE 802.11i
  30. Four-Way Handshake
  31. IEEE 802.11i Considerations