rev

symmetric key- 128bit
asymmetric key-1096 minimum size..
disadvantage of asymmetric key is longer time to encrypt..
hashfunction used in digital signature forauthentication..
hash is one way.. cant be decoded so nt used for encryption..
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ssl..protocol- process.. symmetric and asymmetric used together..
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computer networks and internet:
1.OSI
2.TCP/IP
3.Each layer and there protocol, use.
4.Routing algorithms.
5.Packet header,packet data-hex format.
6.IP addressing,classes,non routable ip addresses..eg:192.168...
7.ARP..link between ip and mac address
8.Subnet,ip subnetting,subnet calculation..
DNS:
classless ip addressing
supernetting
NAT- network address translation protocol
NAT-static/dynamic mapping..
PAT-port address translation/
DNS->uses UDP
uses of UDP
DNS Zones:
authorative/iterative..
Resource REcords(RR)-types
dnsstuff.com
SOA field in dns record.
MX records..
DNS packet..
DNS cache poisoning- avoid by random query id and using pik