CCNA 3 - Capitulo 3.10

CCNA 3 - Capitulo 3.10

1. NETWORK SECURITY CONCEPTS

   • CRIPTOGRAPHY
     • SECURING COMMUNICATIONS
       • FOUR ELEMENTS
         • 4. DATA CONFIDENCIALITY
           • SYMMETRIC ENCRYPTION
             • ONLY AUTHORIZED USERS
             • SYMMETRIC ALGORITHM
               • DATA ENCRYPTION STANDARD (DES)
                 • LEGACY ; INSECURE
                 • STREAM CIPHER OR BLOCK CIPHER
               • TRIPLE 3DES
                 • REPEATS PROCESS DES THREE TIMES
               • ADVANCED ENCRYPTION STANDARD (AES)
                 • MORE EFFICIENT THAN
                   • 3DES
                 • RECOMMENDED SYMMETRIC
                 • NINE COMBINATIONS
                   • KEY AND BLOCK LENGHT
                 • VARIABLE KEY LENGHT
                   • 128 , 192 OR 256 KEY
                 • ENCRYPT BLOCKS THE
                   • 128 ,192 OR 256
               • SOFTWARE OPTIMIZED ENCRYPTION ALGORITHM - SEAL
                 • MORE FAST
                   • DES , 3DES & AES
                 • USES a 160-bit ENCRYPTION KEY
                 • LOWER IMPACT ON THE CPU COMPARED OTHER ALGORITHMS
               • RIVEST CIPHERS (RC)SERIES ALGORITHMS
                 • SECURE WEB TRAFFIC
             • CHARACTERISTICS
               • EACH PARTY KNOWS PRE SHARED KEY
               • SAME KEY ENCRYPT AND DECRYPT
                 • PRE SHARED KEY ; SECRET KEY
                 • THE LONGER THE KEY IT WILL TAKE SOMEONE TO DISCOVER THE KEY
               • KEY ARE SHORT (40 bits - 256 bits)
               • FASTER THAN
                 • ASYMMETRIC ENCRYPTION
               • COMMONLY USED ?
                 • VPN
                 • ENCRYPTING BULK DATA
               • USES LESS CPU RESOURCES THAN ASYMMETRIC
             • TWO CATEGORIES
               • BLOCK CIPHERS
                 • ENCRYPT FIXED SIZED BLOCKS
                 • 64 BIT OR 128 BIT
                 • DES & AES
               • STREAM CIPHERS
                 • ENCRYPT DATA ONE BIT OR BYTE AT A THAM
                 • RC4 AND SEAL
           • EXAMPLE SOFTWARES ENCRYPT DATA ?
             • VERY CRYPT , BITLOCKER