Skip to main content

The Need For Enc The Need For Encryption ryption

The Need For Enc The Need For Encryption ryption

Susceptibility of unencrypted traffic
Password data sniffing
Data manipulation

Authentication manipulation
Equivalent to mailing on postcards
Insecure traditional protocols
telnet FTP POP3 etc. insecure passwords
sendmail NFS NIS etc. insecure information
rsh rcp etc. insecure authentication
While early networking protocols have provided an indispensable infrastructure,secure authentication and
privacy were often not part of their design As a result,today's networking implementations often provide
inadequate protection for the people who use them.
The mathematical field of number theory has provided cryptographic algorithms protocols and techniques
which provide various forms of networking security,including secure authentication,assurance of data
integrity,and privacy.

 Cryptographic Building Blocks

- Random Number Generator
- One Way Hashes
- Symmetric Algorithms
- Asymmetric(Public Key)Algorithms
- Public Key Infrastructures
- Digital Certificates
- Implementations:

open ssl gpg
Encrypted communication protocols are often assembled from a collection of cryptographic techniques In
a building block fashion A protocol will usually provide a selection of one of several similar algorithms to
fill a particular role For example,public key encryption(used for email and other things uses symmetric
encryption for the bulk of the work A selection of symmetric algorithms such as 3DES CAST5 Blowfish
and others)is available for use in this sort of encryption.
An understanding of these underlying cryptographic building blocks is important to understanding higher
level protocols The various building blocks will be examined in the next few pages,including a discussion
of commonly used algorithms and examples of useful applications.
Red Hat Enterprise Linux (RHEL) ships with two different implementations of cryptographic services

Gnu Privacy Guard or gpg which is used to implement file based encryption ensuring file integrity,
encrypting email messages,etc.
open ssl which provides cryptographic libraries that are used in conjunction with network
communications,such as ssl enabled services and ssh The open ssl command provides a command
line interface to many of the services provided by the openss library.

Random Number Generator

Pseudo Random Numbers and Entropy Sources

keyboard and mouse events

block device interrupts

Kernel provides sources

dev random:
best source
blocks when entropy pool exhausted

dev urandom
draws from entropy pool until depleted

falls back to pseudo random generators

openssl rand [base64]num

Many cryptographic routines rely on random numbers which are notoriously difficult to generate using
computers Generally computers use "pseudo random" random number generators,which are often
seeded with integers In order to improve random number generation,the kernel collects an "entropy pool"
based on user events,such as mouse movements,keyboard hits,and disk I/0 operations. The state of the
entropy pool is maintained in the fivar lib random seed between boots as implemented by the
random service script.
Two character devices allow access to the kernel's random number facilities:
dev random will generate random numbers exclusively from the collected entropy poolIf the entropy
pool is exhausted,the process will block until the pool is replenished the mouse is moved try cat
dev random then move your mous
dev urandom will use the entropy pool until it is exhausted and then resort to a fallback pseudo
random algorithm While reads from dev urandom will not block the random numbers are not
as statistically well formed as those provided by dev random though they are still thought to be
cryptographically strong
The openss library also provides a random number generator accessible through the open ssl rand
comimand open ssl rand also accepts a base64 option which uses base64 encoding to generate printable
ASCII text.


Popular posts from this blog

Try winter cough cough Home remedies will run away from this country prescription without any medication Your cold cough

Try winter cough cough Home remedies will run away from this country prescription without any medication Your cold cough

 Friendly winter cough is a common problem in the winter season which is applicable to all people and if the winter season is going on right now then we are ten persons, three persons have this disease.
 And if we get a lot of colds or coughs this season, if we try to take medicine instead of a doctor, this can be relieved.

Let's have friends today what we know about this country remedy

The easiest and easiest way

 Put some salt in warm water and rinse with water. Relieves throat problems as well as drinking hot drinks like tea and coffee and yes, drinking warm water also helps.

 To relieve cold soreness and body aches or headaches
 Add turmeric powder ginger powder and a teaspoon of honey in a glass of warm water. This will provide a lot of relief.

 Native remedy for cold

 Friends find a steam machine in the market and if you want to buy a steam machine, boil hot water …

The DNS Hierarchy

The DNS Hierarchy

DNS is a directory of resource records organized as a tree resource record maps a name to data

klostname to IP address, domain to authoritative nameserver etc.

A domain is a collection of records in the same DNS subtree The root domain consists ol the whole DNS tree

The domain com consists only of names that end in .com hedhat .com is a subdomain of .com which in turn is a subdomain of

Ths part of a domain served by a particular nameserver is called the zone The nameserver is authoritative tor these names

The zone may cover an entire domain, or selected subdomains may be delegated to be served out as Separate zones by other nameservers

The fONOWing definitions are essential to understanding how DNS works Namesen any network device that is running a DNS server.

Resource Record an entry in a zone on the nameserver that maps one thing to anotherie. hostname to Ip address

Domain: a collection of resource records which end in a common name and represent an entire subtree of the DN…

These healthy tips on how to stay healthy in winter

These healthy tips on how to stay healthy in winter

 Eating different types of fruits in the winter improves the body's health by eating figs in winter strengthens bones

 Keeping body healthy in winter season should be taken care of different fresh vegetables and fruits in winter maintains health in our body.
 Winter fruits provide essential nutrients to our body by eating the fruits of winter benefits the body's mushroom tissues.

 Friends today we know what fruits should be eaten in the winter to keep our bodies healthy and which fruits to eat

 By eating bananas every morning from 11 to 12 pm, blood pressure is in control of our body and also keeps the heart healthy.

 The dark circles under the eyes on our face become darker. If we eat apples in winter, it provides a great deal of relief, as well as eating apples every day, we can control our weight and keep skin cancer away.

 Half a cup of cranberries contains about 25 calories if needed.  Consuming it daily i…