CCNA 3 - Capitulo 3.11

CCNA 3 - Capitulo 3.11

1. NETWORK SECURITY CONCEPTS

   • CRIPTOGRAPHY
     • SECURING COMMUNICATIONS
       • FOUR ELEMENTS
         • 4. DATA CONFIDENCIALITY
           • ONLY AUTHORIZED USERS
           • ASYMMETRIC ENCRYPTION
             • ASYMMEETRIC KEY ALGORITHMS
               • PROTOCOLS USES ASYMMETRIC KEY ALGORITHMS
                 • INTERNET KEY EXCHAGE (IKE)
                   • FUNDAMENTALS VPN IPSEC
                 • PRETTY GOOD PRIVACY (PGP)
                   • SECURITY OF EMAIL COMMUNICATIONS
                 • SECURE SOCKET LAYER (SSL)
                   • THIS IS NOW IMPLEMENT IETF STANDARD TRANPORT LAYER SECURITY (TLS )
                 • SECURE SHELL (SSH)
                   • PROVIDE SECURE REMOTE ACCESS TO NETWORK DEVICES , SERVERS ETC
               • ASYMMETRIC ALGORITHMS
                 • RIVEST , SHAMIR AND ADLEMAN ENCRYPTION ALGORITHMS (RSA)
                   • FIRST ALGORITHM SIGNING AS WELL AS ENCRYPTION
                 • DEIGITAL SIGNATURE STANDARD (DSS)
                   • KEY LENGHT
                     • 512 , 1024
                   • SPECIFIES DSA AS THE ALGORITHM FOR DIGITAL SIGNATURES
                   • IS BASED ON ELGAMAL
                   • SIGNATURE CREATION IS SIMILAR TO RSA , BUT IS 10 TO 40 TIMES SLOW FOR VERIFICATION
                 • EL GAMAL
                   • IS BASED ON THE DIFFIE HELMAN KEY AGGREEMENT
                 • ELLIPTIC CURVE TECHNIQUES
                 • DIFFIE HELMAN (DH)
                   • KEY LENGHT
                     • 512 , 1024 , 2048 , 3072 4096
                   • WHATA IS PURPOSE ?
                     • ALLOW TWO PARTIES TO AGREE ON A KEY THAT THEY CAN USE TO ENCRYPT
                   • GENERATE AN IDENTICAL SHARED KEY WITHOUT HAVING COMMUNICATED BEFORE
                   • EXAMPLES DH IS COMMONLY USED
                     • DATA EXCHANGED USING AN IPSEC VPN
                     • DATA IS EXCHANGED USING SSL OR TLS VPN
                 • DIGITAL SIGNATURE ALGORITHM (DSA)
             • CHARACTERISTICS
               • DIFFERENT KEYS ENCRYPT AND DECRYPT
               • KEY LENGHTS LONG (512Bits - 4096Bits)
                 • KEY LENGHTS GREATER THAN OR EQUAL TO 2048 CAN BE TRUSTED
               • SLOWER THAN SYMMETRIC
                 • BASED ON COMPUTATIONAL PROBLEMS
                 • TYPICALLY USED IN LOW VOLUME CRYTPTOGRAPHIC SUCH
                   • DIGITAL SIGNATURES
                   • KEY EXCHANGE
               • COMMONLY USED ?
                 • QUICK DATA TRANSICTIONS
                   • SSH
                   • EX : HTTP
             • ALSO CALLED PUBLIC KEY ALGORITHMS
             • ASYMMETRIC ALGORITHMS USES
               • PUBLIC KEY
               • PRIVATE KEY
             • THE PROCESS IS ALSO REVERSIBLE
           • EXAMPLE SOFTWARES ENCRYPT DATA ?
             • VERY CRYPT