PPT Slide
- Caesar cipher: each letter replaced by another letter, which is three letters behind in the alphabet
- Maximum of 26 attempts to decode Caesar cipher
- Monoalphabetic cipher: Replace a letter with another randomly chosen; Maximum attempts to decode 26!
- One secret key is needed between each pair
- Two standard algorithms for secret key:
- DES (Data Encryption Standard): 64-bit message blocks and 56-bit key
- IDEA (International Data Encryption Algorithm): 64-bit message blocks and 128-bit key
- Message block derived using CBC (Cipher Block Chaining)
- Principle based on rearranging the blocks several times based on predetermined algorithm and secret key
Network Management: Principles and Practice